Co-reporter:Yiwei Qiang, Jingui Jiang, Yachao Xiong, Hao Chen, Jiayun Chen, Shiyou Guan and Jianding Chen
RSC Advances 2016 vol. 6(Issue 12) pp:9772-9778
Publication Date(Web):18 Jan 2016
DOI:10.1039/C5RA27045F
In this paper, nitrogen/phosphorous co-doped porous carbons (N/P-PCs) with hierarchical porosity were prepared by a one-step carbonization method, of which nitrogen-containing PAA/MMF is the precursor and phosphorous-containing sodium hypophosphite monohydrate is the novel pore-forming agent. The synergistic effect of multilevel porosity and heteroatomic functionalities results in good electrochemical performance. Tested as electrode materials for supercapacitors, N/P-PC-50 demonstrates a maximal specific capacitance of 177 F g−1 at a current density of 0.1 A g−1, excellent rate capability (67% capacitance retention at 10 A g−1) and superior cycling stability (no capacitance loss after 10000 cycles). In addition, N/P-PCs have the potential to be used for other applications, and this facile, low-cost and safe synthesis strategy provides a feasible route to develop many hierarchically porous carbon-based materials.
Co-reporter:Jingui Jiang, Luke Bao, Yiwei Qiang, Yachao Xiong, Jiayun Chen, Shiyou Guan, Jianding Chen
Electrochimica Acta 2015 Volume 158() pp:229-236
Publication Date(Web):10 March 2015
DOI:10.1016/j.electacta.2015.01.144
•Nitrogen-doped porous carbons are prepared from poly(acrylic acid)/melamine resin through sol-gel process and KOH activation.•The porous carbon (C-700-1.5) with high specific surface area and nitrogen content exhibits intriguing electrochemical performance.•C-700-1.5 demonstrates superior specific capacitance, excellent rate capability and outstanding cycling durability.•High specific surface area, synergy of the micropore and mesopores, nitrogen functionalities contribute to the superior performance of C-700-1.5.A rich nitrogen-doped porous carbon with high specific surface area and superior specific capacitance for supercapacitors is synthesized from poly(acrylic acid)/methylated melamine-formaldehyde resin through sol-gel process at ambient temperature for 24 hrs, followed by calcination and carbonization at 350 °C and 500 °C for 1 hour respectively and KOH activation at 700 °C for 2 hours under N2 atmosphere. The porosity and surface chemistry of the rich nitrogen-doped porous carbon are swiftly manipulated by KOH activation, with the specific surface area increasing from 14.2 to 2674 m2 g−1 and nitrogen content varying from 20.3 to 8.8 by wt.%, respectively. The porous morphology and nitrogen functionalities enable the nitrogen-doped porous carbon to perform an intriguing electrochemical performance in 1 M H2SO4 aqueous electrolyte, such as a superior specific capacitance at the current density of 0.2 A g−1 (280 F g−1), excellent rate capability (171 F g−1 remained at 10 A g−1) and outstanding cycling durability (no capacity decay after 9000 cycles), which make it a promising electrode material for high performance supercapacitors.Sol-Gel process-derived rich nitrogen-doped porous carbon through KOH activation for supercapacitors
Co-reporter:Jingui Jiang, Min Zhou, Hao Chen, Zhao Wang, Luke Bao, Shiyong Zhao, Shiyou Guan, Jianding Chen
Electrochimica Acta 2015 Volume 168() pp:300-307
Publication Date(Web):20 June 2015
DOI:10.1016/j.electacta.2015.04.033
•Hierarchically porous carbon for supercapacitors was synthesized using Poly (acrylic acid salt)/Polyol.•The carbon (C-700-2.0) demonstrates superior specific capacitance, excellent rate capability and outstanding cycling durability.•High specific surface area and the synergistic effect of the hierarchical pores contribute to the superior performance of C-700-2.0.Hierarchically porous carbon with micropores, mesopores, macropores and high specific surface area for supercapacitors is fabricated from an aqueous curable composition by curing and subsequent carbonization, followed by KOH activation under N2 atmosphere. With the manipulation of KOH activation to the peculiar morphology developed during carbonization, the external specific surface area grows from 208 to 1151 m2 g−1, while the specific surface area of micropores stays at around 1100 m2 g−1, leading to the micro/external specific surface area ratio decreases from 5.36 to 0.94. Prepared with KOH/carbon weight ratio at 2.0, the porous carbon with total specific surface area of 1590 m2 g−1 and moderate micro/external specific surface area ratio of about 2.0, exhibits intriguing electrochemical performance in 1 M H2SO4 aqueous electrolyte, such as superior specific capacitance (274 F g−1 at 0.1 A g−1), excellent rate capability (161 F g−1 remained at 20 A g−1) and outstanding cycling stability (no capacitance loss over 5000 cycles). The promising electrochemical performance could be attributed to the synergy of the hierarchically porous morphology and high specific surface area.Novel hierarchically porous carbons are prepared using Poly (acrylic acid salt)/Polyol as precursor by KOH activation and exhibit superior electrochemical capacitive performance.
Co-reporter:Yeqian Chu;Zhen Lu;Junjie Li;Yun Zhu;Shengmiao Zhang;Jiing Chen
Polymers for Advanced Technologies 2015 Volume 26( Issue 6) pp:606-612
Publication Date(Web):
DOI:10.1002/pat.3493
Honeycomb monolith structured porous poly (L-lactic acid, PLA) was simply fabricated by employing a unidirectional freeze-casting technique. Dimethyl sulfoxide (DMSO) was used as a solvent for PLA, and the solution was unidirectionally frozen. The DMSO was nucleated in the solution and was grown in the freezing direction. The PLA was solidified and structured with the DMSO crystal as a template. Then DMSO was leached by water, ethanol, or the mixture of them, and subsequently the porous PLA was dried by oven. It was found that the freeze-casting protocol can significantly influence the morphological features such as the tube diameter and wall thickness of tube can be tuned by varying of PLA concentration, freezing temperature, and the nature of leaching solvent. Because DMSO has a special solubility of a number of polymers, this method may be a general way for designing and preparing aligned porous materials. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Mengjun Cai, Xie Gao, Jianding Chen
Journal of Molecular Structure 2015 Volume 1086() pp:93-98
Publication Date(Web):15 April 2015
DOI:10.1016/j.molstruc.2014.12.039
•A novel complex (H5O2)(pydaH)2Eu(pydc)3⋅2H2O (1) is reported.•Di-hydronium ion, H5O2+, exists in the crystal lattice of complex 1.•Complex 1 shows a three-dimensional supramolecular framework.•Complex 1 is held together by ion pairing, H-bonding and π–π stacking interactions.•Complex 1 exhibits a red emission under ultraviolet light.In this paper, we reports on the structure of europium(III) complex, in short (H5O2)(pydaH)2Eu(pydc)3⋅2H2O (pyda = 2,6-pyridinediamine, pydc = 2,6-pyridinedicarboxylate), obtained from europium(III) nitrate with a proton transfer compound containing 2,6-pyridinedicarboxylate and 2,6-pyridinediammonium by ultrasonic method. This complex was characterized by means of single-crystal X-ray diffraction, Rietveld refinement, elemental analysis, infrared spectroscopy, thermogravimetric analysis and fluorescence spectra. The X-ray crystal structure analysis reveals that the 3D networks of complex (H5O2)(pydaH)2Eu(pydc)3⋅2H2O are held together by ion pairing, H-bonding, and π–π stacking interactions. Moreover, the solid-state fluorescence spectra of complex exhibit a red emission under ultraviolet light.A novel rare metal complex, (H5O2)(pydaH)2Eu(pydc)3⋅2H2O (pyda = 2,6-pyridinediamine, pydc = 2,6-pyridinedicarboxylate) was synthesized and characterized. The X-ray crystal analysis reveals that the 3D framework of the complex is held together by metal-ligand coordination, ion pairing, H-bonding, and π–π stacking interactions. The solid-state fluorescence spectra exhibit a red emission under ultraviolet light.
Co-reporter:Yun Zhu;Ye Hua;Shengmiao Zhang;Yanhua Wang
Journal of Polymer Research 2015 Volume 22( Issue 4) pp:
Publication Date(Web):2015 April
DOI:10.1007/s10965-015-0703-9
A novel polymeric support for heterogeneous photocatalytic reactions was fabricated by using a multiple O/W/O emulsion as the template, which was an open-cell macroporous bead with photocatalyst titanium dioxide (TiO2) nanoparticles embedded in the void surface. The beads exhibited high photocatalytic efficiency, up to 99.4 % methyl orange could be degraded in 2.5 h photocatalysis in the water containing the bead of 0.46 wt%. Moreover, stable cyclic usage in wastewater treatment was proved to be feasible, and not any decrease in the photocatalytic performance was found for the use in their later 9 cycles, which make the bead material an ideal and potential photocatalyst in wastewater industry.
Co-reporter:Yunhe Su, Yihua Zhu, Hongliang Jiang, Jianhua Shen, Xiaoling Yang, Wenjian Zou, Jianding Chen and Chunzhong Li
Nanoscale 2014 vol. 6(Issue 24) pp:15080-15089
Publication Date(Web):15 Oct 2014
DOI:10.1039/C4NR04357J
Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arising from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than those of Pt/C and most of the non-precious metal catalysts in previous studies. Furthermore, the Co/N-C composite also shows better bifunctional catalytic activity than its oxidative counterparts, which could be attributed to the high specific surface area and the efficient charge transfer ability of the composite, as well as the good synergistic effect between N-doped carbon and the Co nanoparticles in the Co/N-C composite.
Co-reporter:Yunhe Su, Hongliang Jiang, Yihua Zhu, Wenjian Zou, Xiaoling Yang, Jianding Chen, Chunzhong Li
Journal of Power Sources 2014 Volume 265() pp:246-253
Publication Date(Web):1 November 2014
DOI:10.1016/j.jpowsour.2014.04.140
•Hierarchical porous iron and nitrogen co-doped carbons have been successfully prepared.•The synthesized HP–Fe–N–Cs show efficient ORR catalytic activities in neutral media.•The HP–Fe–N–C-900 shows comparable MFCs performance to the commercial Pt/C catalyst.Hierarchical porous iron and nitrogen co-doped carbons (HP–Fe–N–Cs) as efficient cathode catalysts for oxygen reduction reaction (ORR) in neutral media are reported. The HP–Fe–N–Cs are prepared by using polypyrrole as nitrogen source and poly(vinyl alcohol) (PVA) hydrogel-based composites as in-situ templates. In studying the effect of the iron and the hierarchical porous structure on the nitrogen-doped carbon support for ORR, we find that HP–Fe–N–Cs show more positive onset potential, higher cathodic current density, and higher electron transfer number for the ORR in neutral media than iron-free hierarchical porous nitrogen-doped carbon (HP–N–C) and non-hierarchical porous iron and nitrogen co-doped carbon (Fe–N–C), highlighting the importance of the iron and the hierarchical porous structure for improving the ORR performance. Furthermore, HP–Fe–N–Cs show better durability than the commercial Pt/C catalysts in neutral media, and the microbial fuel cells (MFCs) equipped with HP–Fe–N–Cs catalysts on cathodes exhibit comparable power outputs with those of MFCs with commercial Pt/C cathode catalysts.
Co-reporter:Shengguang Weng;Zhean Xia;Jiing Chen;Luanluan Gong
Journal of Applied Polymer Science 2013 Volume 127( Issue 1) pp:748-759
Publication Date(Web):
DOI:10.1002/app.37768
Abstract
The shape memory properties of polycaprolactone-based polyurethanes (PCLUs) synthesized via a novel route of reactive extrusion were investigated in terms of the deformation amplitude, temperature, and rate by differential scanning calorimetry (DSC), dynamic mechanical analyzer, and polarized optical microscopy (POM). DSC analysis shows that the crystalline melting temperature and crystallinity of PCLU increased monotonically with increasing the average polymerization degree of poly(ε-caprolactone) (PCL) block. The retract force increased with increasing the temperature and reached the maximum (6–7 MPa) within 45–55°C. Furthermore, a modified model with two recovery stages was postulated to elucidate the shape memory process, which is visually presented by POM analysis. The two stages of tensile and compressive recovery are distinguished by the inflexion temperature, within 43–48°C and 64–66°C, respectively. The shape fixity is about 60–70% and can be improved to 100% by choosing proper deformation temperature. The tensile deformation recovery ratio was 80–98% due to the water absorption, whereas the compressive deformation recovery ratio was almost 100%. Besides, recovery tests show that the lowest recovery temperature ranged from 24 to 47°C was influenced by the deformation temperature, rate and the PCL block . Thus, the shape memory properties can be adjusted according to different purposes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Ye Hua, Yeqian Chu, Shengmiao Zhang, Yun Zhu, Jianding Chen
Polymer 2013 Volume 54(Issue 21) pp:5852-5857
Publication Date(Web):4 October 2013
DOI:10.1016/j.polymer.2013.08.055
Water-in-oil (W/O) high internal phase emulsions (HIPEs) were prepared by utilizing water-dispersible copolymer particle stabilizer, whose concentration in the internal phase could reach as high as 12.0 wt% (equivalent to 52 wt% relative to the continuous phase). Accordingly, the macroporous materials with high content of skeleton substance would be obtained by the dissolving of these copolymer particles into the continuous phase and without any chemical reaction. And the morphology, the density and the mechanical property of the macroporous materials could be easily tailored through varying the standing time after emulsification, particle concentration in the aqueous phase and the internal phase volume ratio.
Co-reporter:Shengguang Weng;Zhean Xia;Jiing Chen;Luanluan Gong ;Ruijun Xu
Journal of Applied Polymer Science 2012 Volume 124( Issue 5) pp:3765-3773
Publication Date(Web):
DOI:10.1002/app.35366
Abstract
Polyurethanes with multiblock copolymers of poly(ϵ-caprolactone) (PCL) and poly(tetramethylene oxide) glycol (PTMG) or poly(ethylene glycol) (PEG) as a soft segment were synthesized in situ via reactive extrusion from ϵ-caprolactone (CL) and 4,4′-diphenylmethane diisocyanate (MDI). The titanium alkoxide mixture generated from an ester-exchange reaction between titanium propoxide [Ti(OPr)4], and excessive PTMG or PEG was used as an initiator and catalyst. Compared to the reported fabrication of polycaprolactone-based polyurethane (PCLU), the in situ reactive extrusion preparation not only explored a new rapid route for the fabrication of PCLU but also offered a simplified, controllable approach for the production of PCLU in a successive mass scale. A series of PTMG–PCLUs and PEG–PCLUs with different PCL block-average degrees of polymerization (DPn's) were prepared by only an adjustment of the relative concentration of CL in the reaction system, with a certain constant molar ratio of MDI to titanium alkoxide. 1H-NMR, gel permeation chromatography, and differential scanning calorimetry results indicate that all of the CL monomers were converted in the polymerization, and the molecular weight of the copolymers was about 8 × 104 g/mol with a polydispersity index of approximate 2.4. With an increase in the PCL block-average DPn in PTMG–PCLU from 25 to 40, the tensile strength increased from 16.5 to 22.7 MPa, and the melting point increased from 46.1 to 49.5°C. It was also verified by PEG–PCLU prepared with organic Ti of lowered content in the initiator mixture that the mechanical properties could be greatly affected and dropped with decreasing content of organic Ti in the initiator mixture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Tinglan Wang;Songchao Tang ;Jiing Chen
Journal of Applied Polymer Science 2011 Volume 122( Issue 3) pp:2146-2158
Publication Date(Web):
DOI:10.1002/app.34335
Abstract
Changes of morphology and mechanical behavior of isotactic polypropylene (iPP) due to equal channel angular extrusion (ECAE) were investigated. The iPP specimens were processed for up to two passes in the same direction (route A), with the specimens rotate 180°around loading axis after the previous pass (route C). The macroscopic observation showed that high level of shear strain is introduced in iPP extruded twice in route A. Reflected optical microscopy revealed that the original spherulites are elongated into ellipsoidal shape along the shear direction in route A, and the recovery of the spherulitic shape occurred in iPP extruded in route C. X-ray diffraction results and the dynamic mechanical analysis showed that the crystalline and amorphous phase are prone to orientation more favorably via route A than route C. The increase of the dynamic storage modulus (E′) indicated that iPP becomes stiffer than other samples when extruded twice in route A. Izod impact testing results demonstrated that the ECAE-deformed spherulites influence the crack propagation direction. The impact strength of iPP is greatly improved to 490.5 J/m after processed twice in route A, 10 times of that of un-deformed reference sample. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Shengmiao Zhang, Yun Zhu, Ye Hua, Corinne Jegat, Jianding Chen, Mohamed Taha
Polymer 2011 Volume 52(Issue 21) pp:4881-4890
Publication Date(Web):29 September 2011
DOI:10.1016/j.polymer.2011.08.022
Stable water-in-oil (w/o) high internal phase emulsions (HIPEs) having an internal phase of up to 95 vol% were prepared. The poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) copolymer particles were used as stabilizer. The HIPEs prepared with addition of copolymer particles to the aqueous phase were stabilized by copolymer particles initially, followed by the mixture of copolymer particles and copolymer as the particles eventually dissolves in the organic phase, and finally by only copolymer. Stable w/o HIPEs having an internal phase of up to 92 vol% were also formed with P(St-MMA-AA) copolymer dissolved in the organic phase as the sole stabilizer. Porous polymers (polyHIPEs) were prepared based on these two types of surfactant-free HIPEs. The morphology of the polyHIPEs, such as the surface roughness of the voids and average void diameter, were tailored by tuning the internal phase volume fraction, NaCl, copolymer, and crosslinker concentrations.
Co-reporter:Mengjun Cai, Jianding Chen, Mohamed Taha
Inorganic Chemistry Communications 2010 Volume 13(Issue 1) pp:199-202
Publication Date(Web):January 2010
DOI:10.1016/j.inoche.2009.11.015
Two novel complexes, Na3Y(pydc)3·12H2O (1) and Y2(pydc)(OH)4·3H2O (2) (pydc = 2,6-pyridinedicarboxylate), were synthesized by yttrium (III) nitrate and pydcH2 with different molar ratios. The elemental analysis, IR spectra and single crystal X-ray diffraction were used to determine the structure of complexes. The thermal decompositions and antimicrobial activities against Bacillus coli and Staphylococcus aureus were recorded and interpreted for both.Two novel complexes, Na3Y(pydc)3·12H2O (1) and Y2(pydc)(OH)4·3H2O (2) (pydc = 2,6-pyridinedicarboxylate), have been synthesized by the reaction of yttrium (III) nitrate with pydcH2 in different molar ratios, and characterized by elemental analysis and IR. Thermal decompositions and antimicrobial activities against Bacillus coli and Staphylococcus aureus have been recorded and interpreted for both. The crystal structure of complex 1 is determined by single crystal X-ray diffraction and the possible structure of complex 2 is also described.
Co-reporter:Yun Zhu;Shengmiao Zhang;Jiing Chen;Chun Pu Hu
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 19) pp:4356-4360
Publication Date(Web):
DOI:10.1002/pola.24221
Co-reporter:Shengmiao Zhang and Jianding Chen
Chemical Communications 2009 (Issue 16) pp:2217-2219
Publication Date(Web):06 Mar 2009
DOI:10.1039/B819101H
Open porous PMMA based foams have been synthesized from surfactant-free high internal phase emulsion templates.
Co-reporter:Shengmiao Zhang;Jiing Chen;Mohamed Taha
Journal of Applied Polymer Science 2009 Volume 114( Issue 3) pp:1598-1605
Publication Date(Web):
DOI:10.1002/app.30744
Abstract
Monodisperse styrene/methyl methacrylate/acrylic acid (St/MMA/AA) copolymer microspheres have been prepared with surfactant-free emulsion polymerization in air. The presence of oxygen in the system not only caused an induction period but also decreased the average particle size (Dp). However increasing AA concentration ([AA]) gave a reduction in the induction period. The FTIR and NMR analysis of the latex copolymer confirmed that the correlation of the copolymer compositions with the feed compositions was much better at the lower [AA] than at the higher levels. The AA contents of the copolymers obtained in air were much lower than those of the copolymers obtained under N2 protection. Decreasing [AA] led to decrease in the copolymer molecular weight and broadening of the molecular weight distribution, but the particle size distribution (δ/Dp) was unaffected. In addition, the average particle diameter (Dp) was proportional to [AA]–0.255, and increasing comonomers feed content caused linear increase of Dp, and a monodisperse sample with final solids contents up to 34.2 wt % was obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Shengmiao Zhang, Jianding Chen, V. Tamara Perchyonok
Polymer 2009 50(7) pp: 1723-1731
Publication Date(Web):
DOI:10.1016/j.polymer.2008.11.004
Co-reporter:Shengmiao Zhang and Jianding Chen
Chemical Communications 2009(Issue 16) pp:NaN2219-2219
Publication Date(Web):2009/03/06
DOI:10.1039/B819101H
Open porous PMMA based foams have been synthesized from surfactant-free high internal phase emulsion templates.
![Poly[oxy(2,2-dimethyl-1,3-propanediyl)oxy(1,6-dioxo-1,6-hexanediyl)]](http://img.cochemist.com/ccimg/28100/28039-87-4.png)
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![POLY[OXY[(1R)-1-METHYL-2-OXO-1,2-ETHANEDIYL]]](http://img.cochemist.com/ccimg/27000/26917-25-9.png)
![POLY[OXY[(1R)-1-METHYL-2-OXO-1,2-ETHANEDIYL]]](http://img.cochemist.com/ccimg/27000/26917-25-9_b.png)
![1-[6-(2,5-dioxopyrrol-1-yl)hexyl]pyrrole-2,5-dione](http://img.cochemist.com/ccimg/4900/4856-87-5.png)
![1-[6-(2,5-dioxopyrrol-1-yl)hexyl]pyrrole-2,5-dione](http://img.cochemist.com/ccimg/4900/4856-87-5_b.png)
![Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]](http://img.cochemist.com/ccimg/26200/26161-42-2.png)
![Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]](http://img.cochemist.com/ccimg/26200/26161-42-2_b.png)