Co-reporter:Li Sha, Shiping Huang
International Journal of Hydrogen Energy 2017 Volume 42, Issue 27(Volume 42, Issue 27) pp:
Publication Date(Web):6 July 2017
DOI:10.1016/j.ijhydene.2017.05.194
•H2O adsorption and dissociation on Pd13−nNin@Pt42 nanoparticles are investigated.•Adding Ni atoms in the core of the Pd13@Pt42 is unbeneficial for H2O dissociation.•Linear coefficient between adsorption energy of OH and d-band center of Pt is 0.99.•Ni13@Pt42 is the most active catalyst for H2O dissociation among Pd13−nNin@Pt42 NPs.Density functional theory calculations are performed to investigate H2O adsorption and dissociation properties on the icosahedral Pd13−nNin@Pt42 (n = 0, 1, 12, and 13) tri-metallic core-shell nanoparticles. The adsorption of H2O adsorption on the vertex sites of Pd13−nNin@Pt42 (n = 0, 1, 12, and 13) nanoparticles, while the adsorption of OH on the bridge site (B1) is preferred, and H is easily absorbed on the vertex and bridge sites. In addition, the reaction pathways of H2O dissociation on the top of vertex atom (V1) and top of the edge atom (V2) sites of Pd13−nNin@Pt42 (n = 0, 1, and 12) nanoparticles, and V1 of the Ni13@Pt42 are analyzed to explore the H2O dissociation machanisms. It is found that the addition of Ni atoms in the core of the Pd13@Pt42 is unbeneficial for the breakage of the OH bond for H2O dissociation on the Pd13−nNin@Pt42 (n = 1 and 12) except Ni13@Pt42 nanoparticle. Moreover, for the Pd13−nNin@Pt42 (n = 0, 1, 12, and13) nanoparticles catalysts, the activity of H2O dissociation reaction follows the order of Ni13@Pt42 > Pd13@Pt42 > Pd12Ni1@Pt42 > Pd1Ni12@Pt42, illustrating that the Ni13@Pt42 is the strongest activity among of the Pd13−nNin@Pt42 (n = 0, 1, 12, and13) nanoparticles catalysts. Therefore, tuning the composition of Pd and Ni in the core of the Pd13−nNin@Pt42 nanoparticles catalysts, the activity of Pd13−nNin@Pt42 (n = 0, 1, 12, and 13) nanoparticles catalysts can be modulated effectively.Download high-res image (149KB)Download full-size image
Co-reporter:Ping Cheng, Yongpeng Yang, Shiping Huang
Journal of Molecular Graphics and Modelling 2017 Volume 74(Volume 74) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.jmgm.2017.03.014
•Effects of ionic liquid on stabilization of 13-atom Pt-Ru clusters is performed by DFT.•Anions of PF6− and CF3SO3− can better improve the stability of Ru7Pt6.•Stabilities of Ru4Pt9, Ru7Pt6, and Ru9Pt4 are enhanced interacting with [BMIM][CF3SO3].•The steric protection plays the primary role in Ru7Pt6–4{[BMIM][CF3SO3]}.Density functional theory has been performed to systematically study the interactions between RunPt13-n (n = 4, 7 and 9) clusters and [BMIM]+ based ionic liquids. Ionic liquids [BMIM][Br], [BMIM][BF4], [BMIM][PF6], [BMIM][CF3SO3], and [BMIM][NTf2] have different effects on the stability of Ru7Pt6. Ionic liquids with median size anions of PF6− and CF3SO3− can better improve the stability of Ru7Pt6 than those with the small anions of Br− and BF4− and large anion of NTf2−. Based on negative relaxation energies, the stabilities of Ru4Pt9, Ru7Pt6, and Ru9Pt4 are all enhanced after interacting with [BMIM][CF3SO3]. The stability enhanced degree is in agreement with the interaction strength. For Ru7Pt6–n{[BMIM][CF3SO3]} (n = 1, 2, 3, 4), the interaction between ionic liquid and cluster plays the primary role in stabilizing the cluster in Ru7Pt6–[BMIM][CF3SO3]. With the increase of the number of [BMIM][CF3SO3], the role of the interaction in stabilizing the cluster is getting weaker, while the role of steric protection is getting more important.Download high-res image (154KB)Download full-size image
Co-reporter:Xiangliang Ma, Shangguo Liu, Shiping Huang
International Journal of Hydrogen Energy 2017 Volume 42, Issue 39(Volume 42, Issue 39) pp:
Publication Date(Web):28 September 2017
DOI:10.1016/j.ijhydene.2017.08.086
•Adding Ti or Nb atom into Mg55 nanocluster is beneficial to enhance the stability.•Nb-dopant Mg55 nanoclusters can generate lower activation barrier for H2 dissociation.•Surface and subsurface positions are the better substitutional sites for Ti and Nb atoms.•Addition of Ti and Nb dopants can significantly improve the slow hydrogenation kinetics of magnesium.The slow hydrogenation kinetics and high reaction temperature of Mg primarily limit its application for mobile hydrogen storage. H2 adsorption and dissociation on the pure and TM-doped (TM = Ti, Nb) Mg55 nanoclusters are systematically studied by using density functional theory (DFT) calculations. It is found that the introduction of Ti and Nb atoms into Mg55 nanocluster can greatly modify the electronic structure of Mg55 nanocluster and enhance the stability of system. Through the analyses of results from the climbing image nudged elastic band (CI-NEB) and reaction rate constant, we also find that the energy barriers of H2 dissociation on TM-doped Mg55 nanoclusters can be significantly decreased due to the addition of Ti and Nb. Adding Ti and Nb atoms can dramatically improve the rate constant of H2 dissociation, especially for H2 dissociation on Mg54TM2 (TM atom replacing the inner shell position), Mg54TM3 (TM atom replacing the outermost vertex) and Mg54TM4 (TM atom replacing the outermost edge position) nanoclusters. Moreover, compared with the Ti dopant, the Nb will generate a lower activation barrier for H2 dissociation on TM-doped Mg55 nanoclusters. We also suggest that the subsurface and surface positions (Mg54TM2, Mg54TM3, Mg54TM4) are the ideal substitutional sites for TMs.Download high-res image (255KB)Download full-size image
Co-reporter:Sha Li, Yongpeng Yang, Shiping Huang
Computational and Theoretical Chemistry 2017 Volume 1107(Volume 1107) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.comptc.2017.01.015
•The effect of adding Ni atoms on the structure and properties of Pd13−nNin@Pt42 nanoparticles is investigated.•Stability and magnetic properties of the Pd13−nNin@Pt42 nanoparticles with increasing the number of Ni atoms are enhanced.•Average bond length of Pt-Pt and Bader charge of Pt atoms change linearly with the d-band center of Pt atoms.The structural, electronic and magnetic properties of the icosahedral Pd13−nNin@Pt42 (n = 0–13) nanoparticles have been studied by the density functional theory. With the number of Ni atoms increasing, the excess energies of the Pd13−nNin@Pt42 (n = 0–13) nanoparticles monotonically decrease, which indicates that the addition of Ni atoms can enhance the stability of the Pd13−nNin@Pt42 (n = 0–13) nanoparticles. The enhanced stabilities of Pd13−nNin@Pt42 (n = 1–13) nanoparticles can be ascribed to the fact that the Ni-Pt interaction is stronger than Pd-Pt interaction. In according to the calculated results of Bader charge, the charge is transferred from Ni and Pd to Pt atoms. It is found that the average bond length of Pt-Pt and average Bader charge of Pt atoms change linearly with the d-band center of Pt atoms. The total magnetic moment of the nanoparticles also increases with the number of Ni atoms increasing, and the maximum value is found at Pd1Ni12@Pt42 (21.21 μB). The total magnetic moment, the average Bader charge and d-band center of Ni atoms display a similar change tendency as a function of Ni atoms. Our calculated results suggest that the addition of Ni atoms can dramatically change the stability, as well as the electronic and magnetic properties of Pd13−nNin@Pt42 nanoparticles.Download high-res image (171KB)Download full-size image
Co-reporter:Sha Li, Yongpeng Yang, Shiping Huang
Applied Surface Science 2017 Volume 410(Volume 410) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.apsusc.2017.03.083
•O2 adsorption and dissociation on Pd13-nNin@Pt42 NPs are performed by DFT.•Adsorption energies of O2 and O are strongly affected by the coordination number.•Adsorption energy and d-band center displays the opposite change tendency.•Ni13@Pt42 is the most active catalyst among Pd13-nNin@Pt42 (n = 0, 1, 12, and 13) NPs.Density functional theory calculations are performed to investigate O2 adsorption and dissociation on the icosahedral Pd13-nNin@Pt42 (n = 0, 1, 12, and 13) tri-metallic nanoparticles. The parallel adsorption of O2 on Pd13-nNin@Pt42 (n = 0, 1, 12, and 13) is stronger than the vertical adsorption. The adsorption of O2 on the bridge site (B1) is favorable in the Pd13-nNin@Pt42 (n = 0, 1, 12, and 13) nanoparticles, while the adsorption of O atom on the hollow site (H1) is preferred. The adsorption energies of O2 and O are strongly affected by the coordination number. Low coordination site shows strong adsorption of O2 and O on the Pd13-nNin@Pt42 (n = 0, 1, 12, and 13) nanoparticles. The adsorption energies of O2 and O atoms are found to be correlated well with the d-band center of surface Pt. For the Pd13-nNin@Pt42 (n = 0, 1, 12, and13) nanoparticles catalysts, the ORR activity follows the order of Ni13@Pt42 > Pd13@Pt42 > Pd12Ni1@Pt42 > Pd1Ni12@Pt42, illustrating that the Ni13@Pt42 is the strongest ORR activity among the Pd13-nNin@Pt42 (n = 0, 1, 12, and13) nanoparticles catalysts. Our results have important significance to understand the mechanism of O2 dissociation on the Pd13-nNin@Pt42 (n = 0, 1, 12, and 13) tri-metallic nanoparticles.Download high-res image (120KB)Download full-size image
Co-reporter:Benlong Wang, Yongpeng Yang, Shiping Huang
Materials Discovery 2017 Volume 7(Volume 7) pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.md.2017.07.001
The structural and electronic properties of icosahedral Ru13@Pt42-nMon (n = 0–18) nanoclusters are studied by the density functional theory. Through the analysis of excess energy, core-shell interaction energy and dissolution potential, we found that the addition of Mo atoms on the surface enhances the stability and dissolution resistance of Ru13@Pt42-nMon (n = 0–18) NCs. The difference charge density and Bader charge show that the electrons transfer from core to shell. Moreover, the trend of electron transfer is confirmed by Bader charge. The Ru atoms lose more electrons with increasing the number of Mo atoms, Pt gaining more electrons when the coordination number of Pt-Mo increases, and Mo donating more electrons if the coordination number of Mo-Pt increases. Besides, the d-band center of Mo exhibits a negative relationship with coordination number of Mo-Pt.Download high-res image (339KB)Download full-size image
Co-reporter:Shangguo Liu, Shiping Huang
Applied Surface Science 2017 Volume 425(Volume 425) pp:
Publication Date(Web):15 December 2017
DOI:10.1016/j.apsusc.2017.07.061
•MoS2 monolayer can prevent Co atoms diffusion and aggregation.•ER and LH mechanisms of CO oxidation are analyzed.•Energy barriers of O-C-O-O intermediate formation is only 0.57 eV in LH mechanism.•MoS2 monolayer can serve as single atom catalysts substrate for CO oxidation.We systematic investigated the CO oxidation reaction over a single Co atom supported by MoS2 monolayer (Co/MoS2) on the basis of density functional theory calculations and ab initio molecular dynamics simulations. The binding energy of a single Co atom onto MoS2 monolayer is up to 2.80 eV, making the diffusion and aggregation of supported Co atom difficult. For CO oxidation reaction, both Eley–Rideal and Langmuir–Hinshelwood mechanisms are considered. The energy barriers of CO oxidation through the Langmuir–Hinshelwood mechanism for the rate-limiting step of formation the peroxide-like O-C-O-O intermediate is only 0.57 eV. The relatively high CO oxidation activity of Co/MoS2 may be attributed to the strong electronic resonance among the 3d orbital of the Co atoms and the antibonding 2π* orbitals of adsorbed CO and O2. We proposal that the MoS2 monolayer can serve as a defect-free two dimensional single atom catalysts substrate for CO oxidation reaction. It provides not only a large surface ratio, but also a uniform distribution anchoring points for fixing metal atoms as activation sites. We hope that this work contributes to design more effective nonprecious-metal single-atom catalysts for CO oxidation and widen the applications of monolayer MoS2 materials.Download high-res image (140KB)Download full-size image
Co-reporter:Chuan Liu and Shiping Huang
Dalton Transactions 2016 vol. 45(Issue 27) pp:10954-10959
Publication Date(Web):15 Jun 2016
DOI:10.1039/C6DT01437B
First-principles calculations were performed to investigate the effects of a Fe2O3 cluster on the structural, electronic and dehydrogenation properties of a LiBH4 (001) surface. O atoms interact with Li atoms to form Li–O bonds, corresponding to an experimentally found ternary Li–Fe oxide. The DOS results show that the coupling effect of the spin-unrestricted Fe d orbitals, especially the spin-up state of Fe d orbitals, plays a crucial role in the hybridizations of H s, B p, and Fe d orbitals. The Fe2O3 cluster will serve as the nucleation site of surface activation at the surface of LiBH4 to improve the dehydrogenation kinetics of LiBH4. The doping of the Fe2O3 cluster is advantageous to facilitate the release of a H2 molecule from not only the surface layer but also the inner layer of the LiBH4 (001) surface.
Co-reporter:Yongpeng Yang, Ping Cheng, Shengli Zhang and Shiping Huang
RSC Advances 2016 vol. 6(Issue 6) pp:4354-4364
Publication Date(Web):04 Jan 2016
DOI:10.1039/C5RA25989D
CO dimerization and trimerization on an icosahedral Pt55 cluster were investigated using density functional theory. It is found that the products of CO polymerization depend on the different active sites of the metal surface and CO coverage. C2O2 can be adsorbed on either two neighboring Pt atoms or one Pt atom, and the former case is preferred. The preference can be ascribed to the stronger interaction between the 8σ orbital of C2O2 and 5d orbitals of Pt in the former case, and this interaction increases the stability of C2O2. Two neighboring adsorbed CO molecules (CO*) can capture one free CO to form a ring-opening CO trimer on the Pt surface. High CO coverage can facilitate the dimerization and trimerization of CO and change the preferred adsorption site of C2O2, and highly-coordinated Pt atoms present the superior chemical activity for CO polymerization at high CO coverage. The CO dimerization by two CO* need to overcome a high energy barrier of 1.92 eV, but one CO* can capture one free CO molecule to form the C2O2 with overcoming a much lower energy barrier of 0.87 eV. The energy barrier of CO trimerization is 1.14 eV.
Co-reporter:Chuan Liu, Ning Wang, Shiping Huang
International Journal of Hydrogen Energy 2016 Volume 41(Issue 38) pp:16966-16973
Publication Date(Web):15 October 2016
DOI:10.1016/j.ijhydene.2016.07.206
•Effects of AlH3 vacancy on dehydriding mechanism in NaAlH4 are performed by DFT.•Energy barrier for the migration of AlH3 vacancy along surface (001) is 0.33 eV.•AlH63−AlH63− species formed in NaAlH4 surface (001) and bulk is stable at 300 K.•The transition mechanism of AlH4−AlH4− to AlH63−AlH63− species is suggested.First-principles calculations were performed to study the performance of AlH3 vacancy in the early stage of the dehydrogenation reaction of NaAlH4. AlH3 vacancy tends to exist on the (001) surface rather than in the interior of NaAlH4. The migration of AlH3 vacancy from the subsurface layer to the surface layer is an exothermic process, with an energy barrier of 0.33 eV. The result suggests that enhancing the mobility of AlH3 vacancy along the surface (001) is a feasible approach to facilitate the dehydrogenation reaction of NaAlH4. AlH63−AlH63− anion is observed in this work by importing two AlH3 vacancies, which exists stably at T = 300 K, but decomposes when the temperature increases to 400 K. The formation mechanism of AlH63−AlH63− is that two neighboring AlH4−AlH4− units form two AlH3 vacancies and two remaining H− anions firstly, and then the two remaining H− anions are attracted to AlH4−AlH4− unit to form AlH63−AlH63− anion.
Co-reporter:Ping Cheng, Yongpeng Yang, Nouman Ahmad, Shengli Zhang, Shiping Huang
International Journal of Hydrogen Energy 2016 Volume 41(Issue 6) pp:3844-3853
Publication Date(Web):19 February 2016
DOI:10.1016/j.ijhydene.2016.01.017
•Dissociation of H2O monomer and dimer on Ru55 nanoparticale were performed by DFT.•Ru55 has a high catalytic activity for dissociation of H2O monomer and dimer.•The energy barrier for dissociation of H2O dimer is 0.11 eV.•Proton transfer is found during the dissociation of H2O dimer.The calculation results show that H2O monomer prefers to adsorb at two top sites (t1, t2) of the icosahedral Ru55 nanoparticle. When two H2O molecules coadsorb on Ru55, they choose to adsorb at the two adjacent vertex and edge sites to form a H2O dimer. The energy barrier for H2O monomer dissociation is 0.43 eV on t1 site and 0.34 eV on t2 site after DFT-D2 correction, indicating the t2 site is more active than the t1 site. The energy barrier for H2O dimer dissociation on t2 site (2H2O→TS1step1HOHH2O) is only 0.11 eV after DFT-D2 correction. During H2O dimer dissociation, the H atom from the H2O locating on the t1 site can automatically transfer to the H2O locating on the more active t2 site. The low energy barriers for the dissociation of H2O monomer and dimer illustrate that Ru55 nanoparticles have a high catalyst activity for H2O dissociation to produce hydrogen.
Co-reporter:Lixia Wang, Yongpeng Yang, Ning Wang, Shiping Huang
Computational Materials Science 2016 Volume 117() pp:15-23
Publication Date(Web):May 2016
DOI:10.1016/j.commatsci.2016.01.016
•Electronic properties of Pt55−nNin nanoparticle are performed by DFT calculations.•The structure with more number of Pt–Ni bonds is more stable.•The d-band center and root mean squared d-band width is linear dependent.•Total magnetic moment of Pt1Ni54 with Pt occupies edge site reaches a maximum.The composition-dependent icosahedral (ICO) structures of PtnNi55−n bimetallic nanoparticles (NPs) are explored to investigate the structural, electronic and magnetic properties using density functional theory. The excess energy of the structure with Pt/Ni ≈ 1:1 (Pt28Ni27 NP) is the lowest among the study system. It is noticed that the structures with the greater number of Pt–Ni bonds are more energetically stable on account of the fact that the interaction of Pt–Ni bond is stronger than that of Ni–Ni and Pt–Pt bonds. In addition, the density of states of d-band for Ni and Pt in PtnNi55−n NPs reveals that the Ni d-band has a more remarkable effect on Pt d-band than that of Pt d-band on Ni d-band. Furthermore, the magnetic moments of PtnNi55−n NPs clarify the superior magnetic property. The magnetic moment of Pt54Ni1 NP is larger than that of Pt55 when one Ni atom occupies center, while when the Ni atom occupies surface sites, the magnetic moment of Pt54Ni1 is much lower than that of Pt55. For Pt1Ni54 NP, the magnetism is enhanced comparing with Ni55 when one Pt atom occupies edge site.
Co-reporter:Man Xue;Ping Cheng;Ning Wang;Yunhan Li
Journal of Cluster Science 2016 Volume 27( Issue 3) pp:895-911
Publication Date(Web):2016 May
DOI:10.1007/s10876-016-0967-1
The relationships of structural, magnetic, and electronic properties of bimetallic RhnPt55−n (n = 0–55) clusters with cuboctahedral structure as varying compositions have been investigated using density functional theory calculations. Our results indicate that the Pt atoms tend to segregate to the surface, especially locating at the vertex site, while the Rh atoms prefer to the core site. In random alloy structures, Rh27Pt28 cluster has the lowest excess energy of −2.49 eV. However, the ordered core–shell structure, Rh13@Pt42, has much lower excess energy of −5.16 eV. In addition, our calculations have indicated that the total magnetic moments of bimetallic RhnPt55−n clusters are weakened except the Rh27Pt28 with respect to Rh55 cluster, while the average local magnetic moments of Rh and Pt atoms are mainly enhanced compared with their pure phases. As for the electronic properties, the d-band center (|εd*|) of Rh and Pt as well as the s-, p-, d-partial density of states (s-, p-, d-PDOS) reveal the relationship between the electronic properties and structural stabilities. Meanwhile, the d-PDOS has interpreted the varying magnetic moments.
Co-reporter:Ping Cheng, Chuan Liu, Yongpeng Yang, Shiping Huang
Chemical Physics 2015 Volume 452() pp:1-8
Publication Date(Web):1 May 2015
DOI:10.1016/j.chemphys.2015.02.010
Highlights
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Interaction between PtRu nanoparticle and [BMIM][PF6] is performed by DFT calculations.
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The structure of Pt13Ru42 nanoparticle is distorted induced by [BMIM][PF6].
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The d-band center show that catalytic activities of Pt13Ru42 and Ru55 are enhanced.
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Two C atoms of [BMIM][PF6] form the bond with Pt13Ru42 nanoparticles.
Co-reporter:Ting Yu, Ping Cheng, Shiping Huang, Peng Wang, Huiping Tian
Computational and Theoretical Chemistry 2015 Volume 1057() pp:15-23
Publication Date(Web):1 April 2015
DOI:10.1016/j.comptc.2015.01.008
•Adsorption of thiophene on TM-doped (ZnO)15 nanotube is calculated by DFT calculations.•Doping of transition metal in (ZnO)15 nanotube promotes the activity of thiophene.•There is the π-back donation in the η2 bonding modes.•ν(CS) and ν(CC)sym bands in η2 bonding mode are shifted to lower wavenumber.The adsorption of thiophene on transition metal (Ni/Co/Mn)-doped (ZnO)15 nanotube is investigated using density functional theory calculation. Different adsorption possibilities have been investigated. It is found that the stability of the nanotube increases with the doping of the transition metal (Ni/Co/Mn) atom, and the doping of transition metal (Ni/Co/Mn) atom should be mainly responsible for the reduction of the energy gap. We also observed an elongation of the SC bond in adsorbed thiophene in Ni/Co/Mn-doped (ZnO)15 adsorption systems, compared with those of adsorbed thiophene in pristine (ZnO)15 adsorption systems, illustrating the SC bonds in adsorbed thiophene are active by transition metal atom in Ni/Co/Mn-doped (ZnO)15 nanotubes. Molecular orbital results show that π-backdonation is found in η2 bonding mode. Moreover, compared with the vibrational frequencies of free thiophene, the ν(CC)sym and ν(CS)as bands of η2 bonding mode are shifted to lower wavenumber.
Co-reporter:Shiping Huang, Chuan Liu, Jia Li, Peng Wang, Huiping Tian
International Journal of Hydrogen Energy 2014 Volume 39(Issue 25) pp:13512-13518
Publication Date(Web):22 August 2014
DOI:10.1016/j.ijhydene.2014.02.107
•Synergistic effect of Ti and F co-doping NaBH4 is performed by DFT calculation.•Ti and F co-doped NaBH4 is more stable than Ti-doped NaBH4.•Hydrogen desorption energies decrease as increasing of F atoms.•Dehydrogenation reaction is more likely to form TiB2, B, NaF, and H2.The synergistic effects of Ti and F co-doping on the structure and dehydrogenation properties of NaBH4 are investigated by using density functional theory calculations. The results show that Ti is more likely to substitute Na, while F tends to replace the H in the BH4 unit. It is found that Ti and F co-doped NaBH4 systems are more stable than Ti-doped NaBH4 system. The results of hydrogen desorption energies imply that the co-doped Ti and F decrease the strength of B–H bonds. In addition, the hydrogen desorption energies decrease as increasing the concentration of F atoms. The dehydrogenation reaction of Ti and F co-doped NaBH4 is more likely to form TiB2, B, NaF, and H2.
Co-reporter:Lihong Zhang, Ning Wang, Shengli Zhang and Shiping Huang
RSC Advances 2014 vol. 4(Issue 97) pp:54879-54884
Publication Date(Web):08 Oct 2014
DOI:10.1039/C4RA07761J
Hydrogen adsorption on a B/C/N sheet under different external electric fields is investigated by first-principles calculations. Through the analyses of structural properties of the B/C/N system, we find that NbBf, BbNo, BaNe, and NaBg are more probable to be synthesized. Through molecular dynamics calculations, it was found that the structures for B/N doped graphyne are stable. For NbBf, BbNo, BaNe, and NaBg, the most stable positions for hydrogen adsorption are the H1 sites. For a single H2 adsorbed on a B/C/N sheet, the adsorption energy increases greatly as the electric field increases, and the maximum adsorption energy is 0.506 eV when the electric field is 0.035 a.u. It is also found that the adsorption energy of H2 adsorbed on NbBf under electric field increases faster than H2 adsorbed on other sheets. The interaction between H2 molecule and B/C/N sheet is the Kubas interaction under an external electric field.
Co-reporter:Chuan Liu, Jiali Jiang, Shiping Huang, Peng Wang, Huiping Tian
International Journal of Hydrogen Energy 2014 Volume 39(Issue 26) pp:14178-14183
Publication Date(Web):3 September 2014
DOI:10.1016/j.ijhydene.2014.02.162
Co-reporter:Yonghong Zhang, Chuan Liu, Jiali Jiang, Shiping Huang, Peng Wang, Huiping Tian
International Journal of Hydrogen Energy 2014 Volume 39(Issue 18) pp:9744-9751
Publication Date(Web):15 June 2014
DOI:10.1016/j.ijhydene.2014.04.111
Co-reporter:Yongpeng Yang, Xiangming Wu, Chuan Liu, Shiping Huang
Chemical Physics 2014 Volume 443() pp:45-52
Publication Date(Web):31 October 2014
DOI:10.1016/j.chemphys.2014.08.008
Highlights
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Structures of (NaBH4)n (n = 1–6) clusters are optimized by DFT calculation.
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The Kubas interaction is observed in each cationic cluster.
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Hydrogen molecule interacts with attached boron atom by Kubas interaction.
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Cationic NaBH4 nanoclusters exhibit more easily H2 desorption.
Co-reporter:Lihong Zhang, Shengli Zhang, Peng Wang, Chuan Liu, Shiping Huang, Huiping Tian
Computational and Theoretical Chemistry 2014 Volume 1035() pp:68-75
Publication Date(Web):1 May 2014
DOI:10.1016/j.comptc.2014.02.032
•Effect of electric field on Ti-decorated graphyne is studied by DFT calculation.•Ti-decorated graphyne adsorbs up to four H2 molecules under electric field.•Adsorption energy increases dramatically with the electric field.•Kubas interaction between H2 and Ti-decorated graphyne is observed.Hydrogen adsorption on Ti-decorated graphyne under different external electric fields is explored by first-principles calculations. Through the analyses of structural and electronic properties of pristine and Ti-decorated graphyne, we find that the most favorable adsorption site of Ti atom is the hollow site of a 12-C hexagon. For a single H2 adsorbed on Ti-decorated graphyne, the adsorption energy increases dramatically with the electric field intensity increasing, and the maximum adsorption energy is 0.72 eV when the electric field is 0.014 a.u. The interaction between H2 molecule and Ti-decorated graphyne is Kubas interaction under an external electric field. Each Ti atom can adsorb four hydrogen molecules. The analysis of electronic properties shows that the interaction between Ti and H increases when the electric field is applied. However, the interaction is not as strong as that for a single H2 adsorption.
Co-reporter:Chuan Liu, Shengli Zhang, Shiping Huang, Peng Wang, Huiping Tian
Journal of Alloys and Compounds 2013 Volume 549() pp:30-37
Publication Date(Web):5 February 2013
DOI:10.1016/j.jallcom.2012.09.079
Density functional theory calculations have been used to investigate the structural stability, electronic characteristics and thermodynamic properties of K2ZnH4 hydride. We find that the orthorhombic structure of K2ZnH4 is more stable than the tetragonal structure base on the total energy and phonon density of states. The calculated lattice parameters of the orthorhombic structure of K2ZnH4 are in good agreement with the experimental data. Analysis of the electronic characteristic suggests that K2ZnH4 crystal is an insulating material with a band gap of 4.010 eV. The calculated average H site energy is 4.540 eV/H, demonstrating that strong covalent bond exist between Zn and H atom. The formation enthalpy of K2ZnH4 is found to be −1.318 eV/f.u at 298 K. Hydrogen desorption from K2ZnH4 takes place via a two-step process, firstly forming KH, Zn and H2, and then K and H2. The first decomposition reaction is predicted at 524 K, and the second decomposition reaction is at 505 K. The reaction enthalpy is estimated to be 49.164 kJ/mol at 524 K for the first decomposition reaction, and 62.523 kJ/mol at 505 K for the second decomposition reaction.Graphical abstractHighlights► Structural stability and thermodynamic properties of K2ZnH4 hydride are analyzed. ► Decomposition temperature of two-step reactions is predicted based on free energy. ► Orthorhombic structure of K2ZnH4 hydride is much more stable.
Co-reporter:Chuan Liu, Shengli Zhang, Peng Wang, Shiping Huang, Huiping Tian
International Journal of Hydrogen Energy 2013 Volume 38(Issue 20) pp:8367-8375
Publication Date(Web):9 July 2013
DOI:10.1016/j.ijhydene.2013.04.088
•Confinement effect on LiBH4 is investigated by first-principles calculations.•γ-LiBH4@C31Ti is thermodynamically and dynamically stable.•The new decomposition pathways of γ-LiBH4@C31Ti are predicted.•Confinement effect is beneficial to removal of first and second hydrogen atoms.Confinement effect on the structural, electronic and thermodynamic properties of LiBH4 is investigated by density functional theory. The thermodynamically and dynamically stable confinement structure is testified to be γ-LiBH4@C31Ti according to the adsorption energy and vibrational frequency calculations. The tridentate structure formed by [BH4]− and Li+ in the unconfined LiBH4 changes into bidentate structure in γ-LiBH4@C31Ti. We observe that both the occupied and unoccupied states of H 1s, B 2s, B 2p, Li 2s, and Li 2p orbitals in the partial DOSs of γ-LiBH4@C31Ti shift to high energy level and the splits of DOS peaks occur at the states of H 1s, B 2p, and Li 2p orbitals. Different from the first-step decomposition reaction of LiBH4, the one for γ-LiBH4@C31Ti changes into 2LiBH4@C31Ti → 2LiH + 2B@C31Ti + 3H2. Moreover, the reaction enthalpy for the first-step decomposition reaction of γ-LiBH4@C31Ti decreases to 5.864 eV, which is smaller than that (17.204 eV) of LiBH4. According to the hydrogen removal energy calculations, we observe that the confinement effects make the removal of the first and second hydrogen atoms in γ-LiBH4@C31Ti easy.
Co-reporter:Yonghong Zhang, Hui Ding, Chuan Liu, Shengli Zhang, Shiping Huang
International Journal of Hydrogen Energy 2013 Volume 38(Issue 31) pp:13717-13727
Publication Date(Web):17 October 2013
DOI:10.1016/j.ijhydene.2013.08.038
•LiBH4 inserted with graphite fragments are performed by DFT calculation.•β-H type has the lowest dehydrogenation energy in LiBH4/graphite fragment.•Hydrogen diffusion behaviors are investigated by nudged elastic band method.•Graphite fragments improve the H-exchange kinetics of LiBH4 system.The graphite fragments are used to establish the calculated models of LiBH4 mechanically milled by graphite additive. Density-functional theory calculations have been performed to optimize the crystal structures of LiBH4 inserted by different graphite fragments. It is found that the unsaturated sites introduced by graphite fragments are occupied by BH3 complexes and H atoms. The dehydrogenation energies are calculated to investigate the dehydrogenation ability of LiBH4 with graphite fragments. The results show that BH3 complexes bonded with graphite fragments have lower dehydrogenation energy than pure LiBH4, which is an important factor of the improvement of thermodynamic property of LiBH4 system. The hydrogen diffusion behaviors of graphite fragments doped LiBH4 are investigated by the nudged elastic band method. It is found that the hydrogen diffusion barriers of β-H (the H atoms of BH3 complexes bonding with C atoms) diffusing to other sites are small in the LiBH4/graphite fragment systems. The results show that the existence of β-H type significantly enhances the hydrogen diffusion kinetics of the graphite fragments doped LiBH4.
Co-reporter:Jia Li, Shengli Zhang, Shiping Huang, Peng Wang, Huiping Tian
Journal of Solid State Chemistry 2013 Volume 198() pp:433-439
Publication Date(Web):February 2013
DOI:10.1016/j.jssc.2012.11.003
R3ZnH5 (R=K, Rb, Cs) series have been investigated with respect to the crystal structure, electronic and thermodynamic properties using first-principle methods based on density functional theory with generalized gradient approximation. The optimized structures and atomic coordinates are in good agreement with the experimental data. The strong covalent interactions are obtained between Zn and H atoms in the 18-electron [ZnH4]2− complex, while an ionic interaction is found between [ZnH4]2− and R atom. The formation enthalpies show that the formations of R3ZnH5 hydrides are all exothermic at 298 K. The vibration free energies of R3ZnH5 show that the thermodynamic stabilities of R3ZnH5 hydrides decrease with the increasing diameter of R atom. Two possible decomposition reactions of R3ZnH5 series have been suggested in our work. One (reaction one) is that R3ZnH5 hydrides decomposes to elements directly, and the other (reaction two) is that R3ZnH5 hydrides decomposes to RH hydride. The results show that the first decomposition reaction is more favorable one. The spontaneous decomposition reaction of K3ZnH5 hydrides occur upon 465 K via reaction one, and 564 K via reaction two, respectively.Graphical abstractTotal charge density of K3ZnH5.Highlights► Electronic and thermodynamic properties of R3ZnH5 (R=K, Rb, Cs) were calculated. ► The formations of R3ZnH5 hydrides are all exothermic at 298 K. ► The thermodynamic stabilities decrease with the increasing diameter of R atom. ► Two possible decomposition pathways of R3ZnH5 were investigated.
Co-reporter:Jiali Jiang, Shengli Zhang, Shiping Huang, Peng Wang, Huiping Tian
Computational Materials Science 2013 Volume 74() pp:55-64
Publication Date(Web):June 2013
DOI:10.1016/j.commatsci.2013.03.004
•The rare-earth and alkaline-earth metals play important roles in MMgNiH4.•Two possible decomposition reactions of MMgNiH4 are discussed in details.•Vibration properties suggest that MMgNiH4 hydrides are kinetically stable.•The decomposition temperature of SrMgNiH4 is higher than those of YbMgNiH4 and CaMgNiH4.The role of rare-earth and alkaline-earth metals in determining the properties of MMgNiH4 (M = Yb, Ca and Sr) has been systematically investigated using density functional theory (DFT) and DFT + U methods. The calculated lattice parameters, cohesive energies and elastic parameters are in good agreement with available values. A detailed study of electronic structures shows clearly the ionic interactions between M (M = Yb, Ca and Sr) atoms and NiH4 units, and the main covalent interactions between Ni and H atoms in NiH4 units. Analysis of the bader charge suggests that the degree of ionization of Ca, Sr and Yb atoms decreases in following order: Ca > Sr > Yb. The H site energy (ɛH) is adopted to evaluate the stabilizing effect of rare-earth and alkaline-earth metals. The calculated (ɛH) in H1 (4a) and H2 (12b) sites are 4.7552 and 4.1176 eV/H for YbMgNiH4, which are smaller than the corresponding values of CaMgNiH4 and SrMgNiH4. We also have studied two possible decomposition reactions of MMgNiH4 (M = Yb, Ca and Sr). The results suggest that the feasible decomposition reaction is MMgNiH4→MH2+12MgNi2+12Mg+H2 (M = Yb, Ca and Sr). The vibration properties show that these compounds are kinetically stable.
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang, Peng Wang, Huiping Tian
Chemical Physics Letters 2013 Volume 557() pp:102-105
Publication Date(Web):5 February 2013
DOI:10.1016/j.cplett.2012.11.096
A novel cubane-type ZnO (CBE-ZnO) polymorph is studied by means of the first-principles density functional theory calculations. The results suggest that the CBE-ZnO polymorph is mechanically and dynamically stable. The new CBE-ZnO structure is also energetically more favorable than the previously predicted CsCl-ZnO, BCT-ZnO, and the synthesized RS-ZnO polymorphs. The discovery of CBE-ZnO brings about a complete picture of the extent and nature of polymorphism in ZnO family.Graphical abstractHighlights► A novel cubane-type ZnO polymorph is predicted by first-principles DFT calculations. ► The new ZnO polymorph is mechanically and dynamically stable. ► It is more stable than the previously predicted and synthesized ZnO polymorphs.
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang, Peng Wang, Huiping Tian
Chemical Physics Letters 2013 Volumes 568–569() pp:202
Publication Date(Web):1 May 2013
DOI:10.1016/j.cplett.2013.03.036
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang and Chunru Wang
Nanoscale 2012 vol. 4(Issue 9) pp:2839-2842
Publication Date(Web):16 Mar 2012
DOI:10.1039/C2NR30299C
Widely recognized as the quintessential material, sp2 hybridized carbon material with low dimensions, such as zero-dimensional fullerene, one-dimensional carbon nanotube and two-dimensional graphene, has already compiled an impressive list of superlatives. Quite recently, one-dimensional sp-sp2 hybridized carbon tubular arrays with a wall thickness of about 40 nm and two-dimensional carbon films with the average thickness of 970 nm have been synthesized successfully. Thus, we expect that the existence of a sp-sp2 hybridized zero-dimensional carbon allotrope is possible. A novel and stable zero-dimensional carbon allotrope (fullerenyne) with sp-sp2 hybridization is introduced by means of density functional theory calculation and molecular dynamics confirmation. Unique porous characteristic C96 fullernenyne with an Oh symmetry group exhibits exceptionally high stability. We hope that the present study will lead to a further development of a broad new class of carbon materials.
Co-reporter:Hui Ding, Shengli Zhang, Yonghong Zhang, Shiping Huang, Peng Wang, Huiping Tian
International Journal of Hydrogen Energy 2012 Volume 37(Issue 8) pp:6700-6713
Publication Date(Web):April 2012
DOI:10.1016/j.ijhydene.2012.01.026
Nonmetal atoms (B, C and Si) are designed to add into Mg2Ni hydrogen storage alloy and its hydride. First-principles density-functional theory calculations have been performed to investigate their crystal structures, electronic and thermodynamic properties. The calculation results present that nonmetal additions in Mg2NiH4 show more effective destabilization than metal additions. Especially for B and C, the decreases of formation enthalpies of Mg2NiH4 reach 0.19 and 0.21 eV/atom. The NiH4 structure near B or C in Mg2NiH4 hydride becomes the tripod-like NiH3 structure. The results show that the thermodynamic stabilities of Mg2Ni and Mg2NiH4 exhibit a nearly linear decrease with the increasing content of nonmetal atoms. The calculated dehydrogenation energies are 59.39, 58.12, 55.84 and 55.30 kJ/mol H2 for Mg2NiH4, Mg2NiB0.5H4, Mg2NiC0.5H4 and Mg2NiSi0.5H4, respectively. It is found that the addition of nonmetal atoms favors the dehydrogenation reaction for Mg2Ni hydrogen storage material. In addition, the effects of nonmetals to the heat capacities and vibrational entropies of Mg2Ni and Mg2NiH4 are also analyzed.Highlights► Thermodynamic properties of Mg2Ni and Mg2NiH4 inserted nonmetal are obtained. ► Mg2NiH4 inserted by nonmetal atoms (B, C, Si) shows effective destabilization. ► Dehydrogenation energy of Mg2NiH4 decreases as increasing nonmetal content.
Co-reporter:Yonghong Zhang, Xiaozhen Zheng, Shengli Zhang, Shiping Huang, Peng Wang, Huiping Tian
International Journal of Hydrogen Energy 2012 Volume 37(Issue 17) pp:12411-12419
Publication Date(Web):September 2012
DOI:10.1016/j.ijhydene.2012.06.056
Using density functional theory we have investigated the feasibility of bare and Ni decorated Al12N12 cages for hydrogen storage. In the bare Al12N12 cage, each Al atom is capable of adsorption one H2 in molecular form with the average adsorption energy of −0.165 eV. In addition, it is shown that hydrogen prefers to remain inside the Al12N12 cage with molecular form. In the Ni decorated Al12N12 cage, the most stable site for Ni atom is the bridge site over the Al–N bond shared by the six-membered rings (BH site) out of the cage. Ni atom of the NiAl12N12 cage has been found to adsorb up to three hydrogen molecules. It is demonstrated that up to 20 hydrogen molecules can be stored on the exterior surface and inside of the NiAl12N12 cage with total gravimetric density of 6.8 wt%. As the weight percentage hydrogen storage is increasing to 6.5 wt%, the minimum value of the Gibbs free energy becomes positive at 25 K. It indicates that high weight percentage hydrogen storage cannot be achieved in NiAl12N12 cages.Graphical abstractHighlights► Feasibility of Ni decorated Al12N12 cages are studied for hydrogen storage. ► Ni atom of the NiAl12N12 cage is found to adsorb up to three H2. ► High weight percentage hydrogen storage cannot be achieved in NiAl12N12 cage.
Co-reporter:Xiaozhen Zheng, Yonghong Zhang, Shiping Huang, Hui Liu, Peng Wang, Huiping Tian
Computational and Theoretical Chemistry 2012 Volume 979() pp:64-72
Publication Date(Web):1 January 2012
DOI:10.1016/j.comptc.2011.10.016
Transition metal atoms (Co, Ni and Mo) modified alumina are of interest in hydrodesulfurization catalysis. In this study, full geometry optimization, bonding characters, electronic structures and vibrational analysis for thiophene adsorption on MAl20O30 (M = Co, Ni and Mo) clusters are carried out by density functional theory method. The impurity of transition metal atoms promotes the activity of catalyst by an elongation of the SC bond in all thiophene adsorption modes. The bonding characteristics analysis, based on the values of charge transfer and molecular orbital pictures for different adsorption modes, indicates that π-backdonation exists for η2 and η5 bonding modes. In addition, compared with the vibrational frequencies of free thiophene, the ν(CC)sym bands for η5 bonding mode are shifted to lower wavenumbers, which is consistent with experimental results.Graphical abstractGeometry structures of the (η5-C4H4S)Co(Al20O30).Highlights► The impurity of transition metal promotes the activity of catalyst by an elongation of CS bond. ► There are π-backdonation exists in the η2 and η5 bonding modes. ► The ν(CC)sym bands are shifted to lower wavenumbers in the η5 bonding modes.
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang, Hui Liu, Peng Wang and Huiping Tian
Journal of Materials Chemistry A 2011 vol. 21(Issue 42) pp:16905-16910
Publication Date(Web):13 Jul 2011
DOI:10.1039/C1JM12061A
A beaded ZnO nanocluster as a novel stand-alone system has been introduced by interconnecting different numbers of highly stable (ZnO)12 basic units. Geometries, stabilities, electronic properties, and vibrational spectra of the beaded ZnO nanoclusters have been systematically studied by using density functional theory. The results indicate that the beaded ZnO nanoclusters with large binding energies have high stabilities during their growth process. The energy gaps of the (ZnO)12×n nanoclusters (n ≥ 3) show a relatively slow decrease, indicating that the energy gaps are insensitive to the cluster size for the large clusters. The low-lying highest occupied molecular orbital and the high-lying lowest unoccupied molecular orbital are observed to shift to the top of the low energy levels and the bottom of the high energy levels, respectively, leading to the reduction of the energy gap. In addition, by calculating its energy gap, vertical ionization potential, adiabatic electron affinity, and chemical hardness, we find that the beaded ZnO nanocluster has a higher chemical reactivity during its growth process. Vibrational frequencies of ZnO clusters and nanoclusters are also discussed in detail.
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang, Hui Liu, Peng Wang, Huiping Tian
Carbon 2011 Volume 49(Issue 12) pp:3835-3841
Publication Date(Web):October 2011
DOI:10.1016/j.carbon.2011.05.018
A density functional theory study is performed to understand electronic structures and field emission properties of carbon nanotube–ZnO nanocontacts. The carbon nanotube–ZnO nanocontacts have high energetic stabilities and small energy gaps. The energy gaps of the nanocontacts exhibit an oscillatory behavior as a function of the length of carbon nanotubes. The ionization potentials of all carbon nanotube–ZnO nanocontacts are smaller than 7.155 eV of the ZnO nanocage. The ionization potentials of carbon nanotube–ZnO nanocontacts with more 2 carbon layers exhibit odd–even oscillation in the absence and presence of an electric field. The carbon nanotube–ZnO nanocontact with 4 carbon layers has a smallest ionization potential of 3.625 eV under 0.2 eV/Å external electric field. These results indicate that the field-emission properties of simplex ZnO and carbon nanotube materials can be enhanced significantly by the formation of carbon nanotube–ZnO nanocontacts.
Co-reporter:Rui Jin, Shengli Zhang, Yonghong Zhang, Shiping Huang, Peng Wang, Huiping Tian
International Journal of Hydrogen Energy 2011 Volume 36(Issue 15) pp:9069-9078
Publication Date(Web):July 2011
DOI:10.1016/j.ijhydene.2011.04.172
The structure, vibration, and electronic structure of H2 molecule adsorbed on (ZrO2)n (n = 1–6) clusters were investigated with density functional theory. We found that H2 is easily absorbed on the top Zr atoms of (ZrO2)n (n = 1–6) clusters. The Zr5O10H2 cluster has the lowest binding energies in the ZrnO2nH2 (n = 1–6) clusters. By analyzing vibrational frequency and Mulliken charge, the H–O and Zr–H bonds were found to be formed in different sized ZrnO2nH2 clusters. The dissociation mechanism of H2 shows that the charge transfers from (ZrO2)n cluster to H2 due to the important role of the orbital hybridization between the cluster and H2 molecule. With increasing the number of H2 molecule adsorbed on (ZrO2)n clusters, the adsorption favors to the sites with low coordinate number, and these adsorption modes present a symmetrical tendency.Highlights► H2 is easily absorbed on the top Zr atoms of (ZrO2)n (n = 1–6) clusters. ► The dissociation mechanism of H2 shows charge transfers from (ZrO2)n cluster to H2. ► With increasing number of H2, the adsorption favors to low coordinate sites. ► These adsorption modes present a symmetrical tendency.
Co-reporter:Xiaozhen Zheng, Yonghong Zhang, Shiping Huang, Hui Liu, Peng Wang, Huiping Tian
Applied Surface Science 2011 Volume 257(Issue 15) pp:6410-6417
Publication Date(Web):15 May 2011
DOI:10.1016/j.apsusc.2011.02.009
Abstract
The geometrical, electronic and vibrational properties of pure (Al2O3)n (n = 9, 10, 12, 15) clusters and Ni-doped (Al2O3)9–10 clusters are investigated by density functional theory. There are four different Ni-doped (Al2O3)9 clusters and one Ni-doped (Al2O3)10 cluster taken into account. Compared with the pure clusters, the Ni-doped (Al2O3)9–10 clusters have narrower HOMO–LUMO energy gaps. The results indicate that the impurity of Ni atom is mainly responsible for the reduction of the HOMO–LUMO energy gap. One characteristic vibration band at about 1030 cm−1 is found in the vibrational frequencies of the Ni-doped (Al2O3)9–10 clusters, which is caused by the asymmetric Al–O–Al stretching vibration. Another band at around 826 cm−1 involving the characteristic vibration of Ni–O bond is in good agreement with experimental results.
Co-reporter:Mingxia Yang, Yonghong Zhang, Shiping Huang, Hui Liu, Peng Wang, Huiping Tian
Applied Surface Science 2011 Volume 258(Issue 4) pp:1429-1436
Publication Date(Web):1 December 2011
DOI:10.1016/j.apsusc.2011.09.097
Abstract
CO adsorption on TM-doped magnesia nanotubes (TM = Ni, Pd and Pt) have been studied by using density functional theory. Our calculation results show that CO favors adsorption on TM-doped magnesia nanotubes in the form of C atom bonding with TM atom. Fukui indices analysis clearly exhibits that doping of impurity TM atom allows for a noticeably enhancement of nucleophilic reactivity ability of magnesia nanotube. The adsorption energies demonstrate that CO molecule is more strongly bound on the 3-fold TM atoms than the 4-fold TM atoms. This finding is well confirmed by TM–C bond length, charge transfer and C–O vibrational frequency. The high adsorption energy of 2.55 eV is found when CO adsorbs on 3-fold Pt in Pt-doped magnesia nanotubes, implying the kind of the doping TM atom has a significant influence on the chemical reactivity.
Co-reporter:Rui Jin;Yonghong Zhang;Peng Wang;Pinghui Tian
Chinese Journal of Chemistry 2011 Volume 29( Issue 1) pp:13-20
Publication Date(Web):
DOI:10.1002/cjoc.201190040
Abstract
The stability, infrared spectra and electronic structures of (ZrO2)n (n=3–6) clusters have been investigated by using density-functional theory (DFT) at B3LYP/6-31G* level. The lowest-energy structures have been recognized by considering a number of structural isomers for each cluster size. It is found that the lowest-energy (ZrO2)5 cluster is the most stable among the (ZrO2)n (n=3–6) clusters. The vibration spectra of ZrO stretching motion from terminal oxygen atom locate between 900 and 1000 cm−1, and the vibrational band of ZrOZrO four member ring is obtained at 600–700 cm−1, which are in good agreement with the experimental results. Mulliken populations and NBO charges of (ZrO2)n clusters indicate that the charge transfers occur between 4d orbital of Zr atoms and 2p orbital of O atoms. HOMO-LUMO gaps illustrate that chemical stabilities of the lowest-energy (ZrO2)n (n=3–6) clusters display an even-odd alternating pattern with increasing cluster size.
Co-reporter:Shengli Zhang ; Yonghong Zhang ; Shiping Huang ; Liang Qiao ; Shansheng Yu ;Weitao Zheng
The Journal of Physical Chemistry C 2011 Volume 115(Issue 19) pp:9471-9476
Publication Date(Web):April 27, 2011
DOI:10.1021/jp2018583
Recent experiments have shown that gap opening and work function modulating in graphenes have been obtained by substituting C atoms with B or N atoms. Especially, some efforts have been set on the fabrication of semiconducting graphene nanocomposites. Here we propose an island-shaped graphene–BN nanocomposite for potential applications as field-emission electron sources. The field emission mechanism of the graphene–BN has been investigated by using density functional theory calculations. Our results show that graphene has a high level of emission currents with a low external electric field. The combination of BN nanocage and graphene makes use of the curvature effect and the nitrogenation that induce local charge enhancement. The presence of an BN nanocage allows for an important enhancement of the field emission properties. The graphene–BN nanofabrication perhaps leads to a unique hybrid platform consisting of graphene and nonmetal, paving the way in future field-emission electron sources.
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang, Hui Liu, Huiping Tian
Chemical Physics Letters 2010 Volume 498(1–3) pp:172-177
Publication Date(Web):30 September 2010
DOI:10.1016/j.cplett.2010.08.070
Novel Al-doped six-membered ring silica nanotubes have been studied by using density functional theory. Four different Al-doped silica nanotubes are taken into account. The results indicate that Al-doped silica nanotubes still retain quasi-tube forms. A symmetry breaking of the HOMO and LUMO is observed for Al-doped silica nanotubes. These Al-doped silica nanotubes have smaller HOMO–LUMO energy gaps than that of pure silica nanotube. Al-doped silica nanotubes have a peak at around 900 cm−1 ascribed to Al–O vibrational mode, which is in good agreement with experimental and theoretical results.Graphical abstractThe electronic properties of pure and Al-doped silica nanotubes are investigated by using density functional theory. The figure shows that the isosurfaces of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the silica nanotubes are changed significantly due to doping with Al atoms.Research highlights► Among Al-doped nanotubes, 1Al-ENT has a smallest HOMO–LUMO gap. Addition of Al with different numbers of atoms or different Al-doped sites should be responsible for the reduction of the gap. This effect may provide a valuable pathway of controlling the HOMO–LUMO gap by appropriately doping metal atoms or metal oxides inside silica nanotube. ► Doping of Al atoms could lead to significant symmetry breaking of the HOMO and LUMO for 1Al-ENT, 2Al-NT and 2Al-ENT. The symmetry breaking is accompanied by a transfer charge between the doping of Al atoms and sililca nanotube. ► It should be noted that there is no peak at 900 cm−1 for pure silica nanotube, while Al-doped silica nanotubes have a weak peak at around 900 cm−1, which is ascribed to Al–O vibration mode.
Co-reporter:Shujun Jiang, Shiping Huang, Lijia Qin, Weixia Tu, Jiqin Zhu, Huiping Tian, Peng Wang
Journal of Molecular Structure: THEOCHEM 2010 962(1–3) pp: 1-6
Publication Date(Web):
DOI:10.1016/j.theochem.2010.08.031
Co-reporter:Shengli Zhang ; Yonghong Zhang ; Shiping Huang ; Hui Liu ; Peng Wang ;Huiping Tian
The Journal of Physical Chemistry C 2010 Volume 114(Issue 45) pp:19284-19288
Publication Date(Web):October 28, 2010
DOI:10.1021/jp107780q
The electronic structures and field emission properties of hybrid graphene-ZnO are investigated by density functional theory. The binding energies, energy levels, and the corresponding local electron density distributions of neutral and charged graphene-ZnO in electric fields are analyzed, which show that the electronic structures of graphene-ZnO are modified significantly by the applied electric fields. The reduction of the energy gaps and the change of the electron density distributions of the states in the vicinity of the Fermi level are observed. The work functions of graphene-ZnO decrease linearly with increasing electric fields, which indicate the enhancement of field emission properties. In addition, the ionization potentials decrease drastically with increasing electric fields, which further indicate the improvement of field emission properties of graphene-ZnO. The Hirshfeld charges and the electrostatic potential derived charges are also explored, and it is found that the electron accumulation becomes obvious on the topmost six-membered ring with increasing electric field. Our results show that the graphene-ZnO is a promising candidate for a field emission electron source.
Co-reporter:Ting Li, Shiping Huang, Jiqin Zhu
Chemical Physics Letters 2009 Volume 471(4–6) pp:253-257
Publication Date(Web):26 March 2009
DOI:10.1016/j.cplett.2009.02.059
Abstract
The amorphous GeO2 is generated with the ‘melt-and-quench’ technique, and molecular dynamics simulations are performed to investigate the structural changes from 1 GPa up to 25 GPa. The five- and six-coordinated Ge–O arrangements increase during the pressurized process. The structure is observed to experience compression inside the tetrahedra under the pressure below 5 GPa. The structural transition from tetrahedral to pentahedral dominant structure takes place during 13–15 GPa. The interstitial radius distribution, void size distribution without overlaps, and the bottleneck radius distribution are shown to decrease with the densification of the system. The largest void channels decrease their radii from 3.9 Å at 1 GPa to 1.2 Å at 25 GPa.
Co-reporter:Bingjing Ding, Shiping Huang, Wenchuan Wang
Journal of Molecular Structure: THEOCHEM 2008 Volume 851(1–3) pp:207-212
Publication Date(Web):28 February 2008
DOI:10.1016/j.theochem.2007.11.016
Density functional theory (DFT) was used to assess the potential ReOx structures grafted onto H-ZSM5 by estimating the bond lengths, angles and vibrational spectra of possible Re–Oxo species. The interaction between water molecule and Re-ZSM-5 was investigated for the hydrothermal stabilities of Re-ZSM-5 zeolites at different temperatures. Local structures of one and two H2O molecules adsorbed on the Re-ZSM-5 zeolites reveal that the adsorption mode is changed, when the second H2O molecule is adsorbed. The tetrahedral Re–Oxo center is slightly distorted by the adsorbed water, and the Raman spectra calculated from the optimized structure shift accordingly. The absorption energy Ead is −23.47 and −33.88 kcal/mol for one and two H2O molecules adsorbed on the Re-ZSM-5, respectively. In addition, the calculated thermodynamic results show that Re-ZSM-5 zeolites are very stable at high temperatures.
Co-reporter:Xiangdan Guo, Shiping Huang, Jiawei Teng, Zaiku Xie
Acta Physico-Chimica Sinica 2006 Volume 22(Issue 3) pp:270-274
Publication Date(Web):March 2006
DOI:10.1016/S1872-1508(06)60001-6
Molecular dynamic (MD) quench method and grand canonical Monte Carlo method (GCMC) are used to study the adsorption of water on NanZSM-5 type zeolite. The simulated adsorption isotherm is in good agreement with the experimental data reported in literatures. Based on these facts, adsorption of water on NanZSM-5 with various nSi/nAl ratios is predicted. The simulation results indicated that nSi/nAl ratios of zeolite framework affect the water adsorption and adsorption isotherm greatly and the adsorption amount decreases with the increase in the nSi/nAl ratio. The above observation can be explained by assumption of the charge influence of Na+ cations on the polar water molecules due to the Coulomb force. The adsorbed water molecules are located around Na+ cations and Al atoms on the zeolite framework and the average number around Na+ cations and Al atoms is four at lower loading. However, hydrogen bonds between the adsorbed water molecules and the oxygen atoms on the zeolite framework exist at higher loading. At the same loading, the isosteric heat decreases as the nSi/nAl ratio increases.
Co-reporter:Xiang-Dan Guo;Shi-Ping Huang;Jia-Wei Teng;Zai-Ku Xie
Chinese Journal of Chemistry 2005 Volume 23(Issue 12) pp:1593-1599
Publication Date(Web):22 DEC 2005
DOI:10.1002/cjoc.200591593
Frameworks of NanZSM-5 type zeolites with various Si/Al ratios have been constructed and optimized with molecular dynamic quench simulation. The results show that the structure parameters of NanZSM-5 type zeolite, including the bond length and atomic charges, are consistent with those predicted by ab initio cluster calculations. It was also observed that atomic charges of Si atoms were shifted to higher field in NanZSM-5 type zeolite with lower Si/Al ratio. Then, the adsorption of isobutene on NanZSM-5 with various Si/Al ratios has been investigated using grand canonical ensemble Monte Carlo simulation and Cvff-300-1.01 forcefield. The simulated adsorption amount was in good agreement with the experimental data. Based on these facts, the effects of Si/Al ratio on the adsorption amount and adsorption isotherms of isobutene on NanZSM-5 were predicted. The results indicated that Si/Al ratio was important for the adsorption of isobutene and the adsorption amount was decreased as the Si/Al ratio was increased, which can be explained that the atomic charge of Na+ cation would influence greatly the π electrons of the isobutene double bond due to the Coulomb force. In addition, the adsorption sites of isobutene and interaction energy of isobutene with NanZSM-5 were also discussed.
Co-reporter:Shangguo Liu, Shiping Huang
Carbon (May 2017) Volume 115() pp:
Publication Date(Web):May 2017
DOI:10.1016/j.carbon.2016.12.094
Density functional theory calculations were performed to cast insight into the mechanism of the activation of O2 by Pt single atom and Pt4 nanocluster deposited on single vacancy and different pyridinic N-doped graphene. It is found that the graphene by introducing pyridinic N can make supported Pt single atom and Pt4 nanocluster accumulate more positive polarized charges, which upshift the d-band centers of the supported Pt single atom and Pt4 nanocluster toward the Fermi level. It is also observed that the more pyridinic N in grapheme is, the more positive polarized charges is accumulated by supported Pt single atom and Pt4 nanocluster. The positive charged sites is favour the dissociation of O2. We find that the energy barrier of O2 dissociation almost decrease linearly with the increase Pt positive polarized charges. Our work reveals that the Pt positive polarized charges can act as microscopic driving force for O2 dissociation.
Co-reporter:Chuan Liu and Shiping Huang
Dalton Transactions 2016 - vol. 45(Issue 27) pp:NaN10959-10959
Publication Date(Web):2016/06/15
DOI:10.1039/C6DT01437B
First-principles calculations were performed to investigate the effects of a Fe2O3 cluster on the structural, electronic and dehydrogenation properties of a LiBH4 (001) surface. O atoms interact with Li atoms to form Li–O bonds, corresponding to an experimentally found ternary Li–Fe oxide. The DOS results show that the coupling effect of the spin-unrestricted Fe d orbitals, especially the spin-up state of Fe d orbitals, plays a crucial role in the hybridizations of H s, B p, and Fe d orbitals. The Fe2O3 cluster will serve as the nucleation site of surface activation at the surface of LiBH4 to improve the dehydrogenation kinetics of LiBH4. The doping of the Fe2O3 cluster is advantageous to facilitate the release of a H2 molecule from not only the surface layer but also the inner layer of the LiBH4 (001) surface.
Co-reporter:Shengli Zhang, Yonghong Zhang, Shiping Huang, Hui Liu, Peng Wang and Huiping Tian
Journal of Materials Chemistry A 2011 - vol. 21(Issue 42) pp:NaN16910-16910
Publication Date(Web):2011/07/13
DOI:10.1039/C1JM12061A
A beaded ZnO nanocluster as a novel stand-alone system has been introduced by interconnecting different numbers of highly stable (ZnO)12 basic units. Geometries, stabilities, electronic properties, and vibrational spectra of the beaded ZnO nanoclusters have been systematically studied by using density functional theory. The results indicate that the beaded ZnO nanoclusters with large binding energies have high stabilities during their growth process. The energy gaps of the (ZnO)12×n nanoclusters (n ≥ 3) show a relatively slow decrease, indicating that the energy gaps are insensitive to the cluster size for the large clusters. The low-lying highest occupied molecular orbital and the high-lying lowest unoccupied molecular orbital are observed to shift to the top of the low energy levels and the bottom of the high energy levels, respectively, leading to the reduction of the energy gap. In addition, by calculating its energy gap, vertical ionization potential, adiabatic electron affinity, and chemical hardness, we find that the beaded ZnO nanocluster has a higher chemical reactivity during its growth process. Vibrational frequencies of ZnO clusters and nanoclusters are also discussed in detail.
