Co-reporter:Jing Li, Laihao Luo, Hongwen Huang, Chao Ma, Zhizhen Ye, Jie Zeng, and Haiping He
The Journal of Physical Chemistry Letters March 16, 2017 Volume 8(Issue 6) pp:1161-1161
Publication Date(Web):February 23, 2017
DOI:10.1021/acs.jpclett.7b00017
Fundamental to understanding and predicting the optoelectronic properties of semiconductors is the basic parameters of excitons such as oscillator strength and exciton binding energy. However, such knowledge of CsPbBr3 perovskite, a promising optoelectronic material, is still unexplored. Here we demonstrate that quasi-two-dimensional (quasi-2D) CsPbBr3 nanoplatelets (NPLs) with 2D exciton behaviors serve as an ideal system for the determination of these parameters. It is found that the oscillator strength of CsPbBr3 NPLs is up to 1.18 × 104, higher than that of colloidal II–VI NPLs and epitaxial quantum wells. Furthermore, the exciton binding energy is determined to be of ∼120 meV from either the optical absorption or the photoluminescence analysis, comparable to that reported in colloidal II–VI quantum wells. Our work provides physical understanding of the observed excellent optical properties of CsPbBr3 nanocrystals and would benefit the prediction of high-performance excitonic devices based on such materials.
Co-reporter:Hongwen Huang, Kan Li, Zhao Chen, Laihao Luo, Yuqian Gu, Dongyan Zhang, Chao Ma, Rui Si, Jinlong Yang, Zhenmeng Peng, and Jie Zeng
Journal of the American Chemical Society June 21, 2017 Volume 139(Issue 24) pp:8152-8152
Publication Date(Web):May 25, 2017
DOI:10.1021/jacs.7b01036
The research of active and sustainable electrocatalysts toward oxygen reduction reaction (ORR) is of great importance for industrial application of fuel cells. Here, we report a remarkable ORR catalyst with both excellent mass activity and durability based on sub 2 nm thick Rh-doped Pt nanowires, which combine the merits of high utilization efficiency of Pt atoms, anisotropic one-dimensional nanostructure, and doping of Rh atoms. Compared with commercial Pt/C catalyst, the Rh-doped Pt nanowires/C catalyst shows a 7.8 and 5.4-fold enhancement in mass activity and specific activity, respectively. The combination of extended X-ray absorption fine structure analysis and density functional theory calculations reveals that the compressive strain and ligand effect in Rh-doped Pt nanowires optimize the adsorption energy of hydroxyl and in turn enhance the specific activity. Moreover, even after 10000 cycles of accelerated durability test in O2 condition, the Rh-doped Pt nanowires/C catalyst exhibits a drop of 9.2% in mass activity, against a big decrease of 72.3% for commercial Pt/C. The improved durability can be rationalized by the increased vacancy formation energy of Pt atoms for Rh-doped Pt nanowires.
Co-reporter:Rong He, Jian Hua, Anqi Zhang, Chuanhao Wang, Jiayu Peng, Weijia Chen, and Jie Zeng
Nano Letters July 12, 2017 Volume 17(Issue 7) pp:4311-4311
Publication Date(Web):June 12, 2017
DOI:10.1021/acs.nanolett.7b01334
Engineering electronic properties is a promising way to design nonprecious-metal or earth-abundant catalysts toward hydrogen evolution reaction (HER). Herein, we deposited catalytically active MoS2 flakes onto black phosphorus (BP) nanosheets to construct the MoS2–BP interfaces. In this case, electrons flew from BP to MoS2 in MoS2–BP nanosheets because of the higher Fermi level of BP than that of MoS2. MoS2–BP nanosheets exhibited remarkable HER performance with an overpotential of 85 mV at 10 mA cm–2. Due to the electron donation from BP to MoS2, the exchange current density of MoS2–BP reached 0.66 mA cm–2, which was 22 times higher than that of MoS2. In addition, both the consecutive cyclic voltammetry and potentiostatic tests revealed the outstanding electrocatalytic stability of MoS2–BP nanosheets. Our finding not only provides a superior HER catalyst, but also presents a straightforward strategy to design hybrid electrocatalysts.Keywords: black phosphorus; electron transfer; Hydrogen evolution reaction; molybdenum disulfide;
Co-reporter:Tingting Zheng, Wei Sang, Zhihai He, Qiushi Wei, Bowen Chen, Hongliang Li, Cong Cao, Ruijie Huang, Xupeng Yan, Bicai Pan, Shiming Zhou, and Jie Zeng
Nano Letters December 13, 2017 Volume 17(Issue 12) pp:7968-7968
Publication Date(Web):November 27, 2017
DOI:10.1021/acs.nanolett.7b04430
Exploring efficient and economical electrocatalysts for hydrogen evolution reaction is of great significance for water splitting on an industrial scale. Tungsten oxide, WO3, has been long expected to be a promising non-precious-metal electrocatalyst for hydrogen production. However, the poor intrinsic activity of this material hampers its development. Herein, we design a highly efficient hydrogen evolution electrocatalyst via introducing oxygen vacancies into WO3 nanosheets. Our first-principles calculations demonstrate that the gap states introduced by O vacancies make WO3 act as a degenerate semiconductor with high conductivity and desirable hydrogen adsorption free energy. Experimentally, we prepared WO3 nanosheets rich in oxygen vacancies via a liquid exfoliation, which indeed exhibits the typical character of a degenerate semiconductor. When evaluated by hydrogen evolution, the nanosheets display superior performance with a small overpotential of 38 mV at 10 mA cm–2 and a low Tafel slope of 38 mV dec–1. This work opens an effective route to develop conductive tungsten oxide as a potential alternative to the state-of-the-art platinum for hydrogen evolution.Keywords: Conductive nanosheet; gap states; HER; O vacancies;
Co-reporter:Tao Chen, Sheng Chen, Ping Song, Yuwei Zhang, Hongyang Su, Weilin Xu, and Jie Zeng
ACS Catalysis April 7, 2017 Volume 7(Issue 4) pp:2967-2967
Publication Date(Web):March 17, 2017
DOI:10.1021/acscatal.7b00087
By studying the nanocatalysis of individual Pd nanoparticles (Pd NPs) in two shapes (cube with (100) facet and octahedron with (111) facet) with single-turnover resolution, the facet-dependent activities and dynamics were apparently observed. The results indicate that Pd octahedrons possess higher intrinsic catalytic activity per site than Pd nanocubes. Within a competitive Langmuir–Hinshelwood mechanism, the facet-dependent activities are derived at single-particle level, and the facet-dependent adsorption behaviors of substrate molecules on Pd(111) and Pd(100) are revealed and clarified by theoretical calculation. Furthermore, the facet-dependent restructuring behaviors of the particle surfaces were also observed. This study gives deeper insight into Pd-based nanocatalysts.Keywords: fluorescence microscopy; nanocatalysis; Pd nanoparticles; shape effect; single molecule;
Co-reporter:Wenbo Zhang, Liangbing Wang, Haoyu Liu, Yiping Hao, Hongliang Li, Munir Ullah Khan, and Jie Zeng
Nano Letters 2017 Volume 17(Issue 2) pp:
Publication Date(Web):January 5, 2017
DOI:10.1021/acs.nanolett.6b03967
The d-band center and surface negative charge density generally determine the adsorption and activation of CO2, thus serving as important descriptors of the catalytic activity toward CO2 hydrogenation. Herein, we engineered the d-band center and negative charge density of Rh-based catalysts by tuning their dimensions and introducing non-noble metals to form an alloy. During the hydrogenation of CO2 into methanol, the catalytic activity of Rh75W25 nanosheets was 5.9, 4.0, and 1.7 times as high as that of Rh nanoparticles, Rh nanosheets, and Rh73W27 nanoparticles, respectively. Mechanistic studies reveal that the remarkable activity of Rh75W25 nanosheets is owing to the integration of quantum confinement and alloy effect. Specifically, the quantum confinement in one dimension shifts up the d-band center of Rh75W25 nanosheets, strengthening the adsorption of CO2. Moreover, the alloy effect not only promotes the activation of CO2 to form CO2δ− but also enhances the adsorption of intermediates to facilitate further hydrogenation of the intermediates into methanol.Keywords: Carbon dioxide; charge transfer; d-band center; rhodium; tungsten;
Co-reporter:Xiaochen Shen;Yanbo Pan;Bin Liu;Jinlong Yang;Zhenmeng Peng
Physical Chemistry Chemical Physics 2017 vol. 19(Issue 20) pp:12628-12632
Publication Date(Web):2017/05/24
DOI:10.1039/C7CP01817G
The reaction mechanism and properties of a catalytic process are primarily determined by the interactions between reacting species and catalysts. However, the interactions are often challenging to be experimentally measured, especially for unstable intermediates. Therefore, it is of significant importance to establish an exact relationship between chemical–catalyst interactions and catalyst parameters, which will allow calculation of these interactions and thus advance their mechanistic understanding. Herein we report the description of adsorption energy on transition metals by considering both ionic bonding and covalent bonding contributions and introduce the work function as one additional responsible parameter. We find that the adsorption energy can be more accurately described using a two-dimensional (2D) polynomial model, which shows a significant improvement compared with the current adsorption energy–d-band center linear correlation. We also demonstrate the utilization of this new 2D polynomial model to calculate oxygen binding energy of different transition metals to help understand their catalytic properties in oxygen reduction reactions.
Co-reporter:Ruijie Huang;Zhongti Sun;Sheng Chen;Siyu Wu;Zeqi Shen;Xiaojun Wu
Chemical Communications 2017 vol. 53(Issue 51) pp:6922-6925
Publication Date(Web):2017/06/22
DOI:10.1039/C7CC03643D
Hierarchical metal nanostructures which exhibit an open structure and a high density of twin defects accessible to reactants hold great promise in catalysis. Here, we report a facile synthesis of Pt–Cu hierarchical quasi great dodecahedrons (HQGDs) which present 5-fold symmetry and are composed of multiple ordered branched units with a frame structure. HQGDs evolve from icosahedral seeds with multiple {111} twin planes, followed by the growth of higher-order branches. Owing to the unique frame structure associated with multiple twin defects, HQGDs showed much higher HER catalytic activity and better durability relative to commercial Pt/C.
Co-reporter:Hongwen Huang;Mei Liu;Jing Li;Laihao Luo;Jiangtao Zhao;Zhenlin Luo;Xiaoping Wang;Zhizhen Ye;Haiping He
Nanoscale (2009-Present) 2017 vol. 9(Issue 1) pp:104-108
Publication Date(Web):2016/12/22
DOI:10.1039/C6NR08250E
We report a room-temperature colloidal synthesis of few-unit-cell-thick CsPbBr3 QWs with lengths over a hundred nanometers. The surfactant-directed oriented attachment growth mechanism was proposed to explain the formation of such CsPbBr3 QWs. Owing to the strong quantum confinement effect, the photoluminescence (PL) emission peak of few-unit-cell-thick CsPbBr3 QWs blue-shifted to 430 nm. The ensemble PL quantum yield (PLQY) of the few-unit-cell-thick CsPbBr3 QWs increased to 21.13% through a simple heat-treatment process. The improvement of PLQY was ascribed to the reduction of the density of surface trap states and defect states induced by the heat-treatment process. Notably, the dependence of the bandgap on the diameter with different numbers of unit cells was presented for the first time in 1-D CsPbBr3 QWs on the basis of the produced few-unit-cell-thick CsPbBr3 QWs.
Co-reporter:Xu Zhao;Pengfei Gao;Yu Yan;Xingqi Li;Yulin Xing;Hongliang Li;Zhenmeng Peng;Jinlong Yang
Journal of Materials Chemistry A 2017 vol. 5(Issue 38) pp:20202-20207
Publication Date(Web):2017/10/03
DOI:10.1039/C7TA06172B
Electrochemical water splitting is greatly hindered by the kinetically sluggish oxygen evolution reaction (OER). The development of economical and efficient catalysts with precisely modulated active sites is crucial for exploring the reaction mechanism and promoting the water oxidation process. Herein, we present isolated Au atom-decorated CoSe2 (Au1–CoSe2) nanobelts with precisely engineered active sites for an enhanced OER. Theoretical investigations showed that the decoration of isolated Au atoms could shift up the d-band center and thus lower the H2O adsorption energy of Co active sites. Moreover, the trace amount of Au atoms (0.1 wt%) also ensures the effective exposure of Co active sites and minimizes the use of Au. Both the intrinsically enhanced H2O adsorption and the sufficient exposure of active sites contributed to the remarkable electrocatalytic performance of the Au1–CoSe2 nanobelts. The as-prepared Au1–CoSe2 nanobelts exhibited a 21.1-fold, 5.7-fold, and 1.9-fold higher OER activity relative to pure CoSe2 nanobelts, Au nanoparticle-deposited CoSe2 (AuN–CoSe2) nanobelts, and commercial Ir/C, respectively. This study demonstrates the validity of atomic-scale control of active sites in Co-based catalysts, which could also be extended to the design of highly efficient catalysts for other energy-related processes.
Co-reporter:Min Meng, Zhicheng Fang, Chao Zhang, Hongyang Su, Rong He, Renpeng Zhang, Hongliang Li, Zhi-Yuan Li, Xiaojun Wu, Chao Ma, and Jie Zeng
Nano Letters 2016 Volume 16(Issue 5) pp:3036-3041
Publication Date(Web):April 13, 2016
DOI:10.1021/acs.nanolett.6b00002
Planar nanocrystals with multiple branches exhibit unique localized surface plasmon resonance properties and great promise in optical applications. Here, we report an aqueous synthesis of Pd@AuCu core–shell planar tetrapods through preferential overgrowth on Pd cubic seeds. The large lattice mismatch between the Pd core and the AuCu shell is the key to induce the formation of branches under sluggish reduction kinetics. Meanwhile, the capping effect of cetyltrimethylammonium chloride on the {100} facets of Pd cubes with an aspect ratio of 1.2 can determine the growth direction of AuCu branches to form a planar structure. Through simply varying the amounts of Pd cubic seeds, the sizes of products can be well-controlled in the range from 33 to 70 nm. With the manipulation of sizes, the peak position of in-plane dipole resonance can be adjusted from visible to near-infrared region. Due to the presence of tips and edges in the branches, planar tetrapods exhibited excellent surface-enhanced Raman scattering performance with an enhancement factor up to 9.0 × 103 for 70 nm Pd@AuCu planar tetrapods.
Co-reporter:Fan Nan, Fang-Ming Xie, Shan Liang, Liang Ma, Da-Jie Yang, Xiao-Li Liu, Jia-Hong Wang, Zi-Qiang Cheng, Xue-Feng Yu, Li Zhou, Qu-Quan Wang and Jie Zeng
Nanoscale 2016 vol. 8(Issue 23) pp:11969-11975
Publication Date(Web):19 May 2016
DOI:10.1039/C5NR09151A
This paper describes a facile method for the synthesis of Au/AuAg/Ag2S/PbS core–multishell nanorods with double trapping layers. The synthesis, in sequence, involved deposition of Ag shells onto the surfaces of Au nanorod seeds, formation of AuAg shells by a galvanic replacement reaction, and overgrowth of the Ag2S shells and PbS shells. The resulting core–multishell nanorod possesses an air gap between the Au core and the AuAg shell. Together with the Ag2S shell, the air gap can efficiently trap light, causing strong field confinement and nonlinear enhancement. The as-prepared Au/AuAg/Ag2S/PbS core–multishell nanorods display distinct localized surface plasmon resonance and nonlinear optical properties, demonstrating an effective pathway for maneuvering the optical properties of nanocavities.
Co-reporter:Xianli Liu;Zhicheng Fang;Qi Zhang;Ruijie Huang;Lin Lin;Chunmiao Ye
Nano Research 2016 Volume 9( Issue 9) pp:2707-2714
Publication Date(Web):2016 September
DOI:10.1007/s12274-016-1159-x
Nanomaterials with unique edge sites have received increasing attention due to their superior performance in various applications. Herein, we employed an effective ethylenediaminetetraacetic acid (EDTA)-assisted method to synthesize a series of exotic Bi2Se3 nanostructures with distinct edge sites. It was found that the products changed from smooth nanoplates to half-plate-containing and crown-like nanoplates upon increasing the molar ratio of EDTA to Bi3+. Mechanistic studies indicated that, when a dislocation source and relatively high supersaturation exist, the step edges in the initially formed seeds can serve as supporting sites for the growth of epilayers, leading to the formation of half-plate-containing nanoplates. In contrast, when the dislocation source and a suitably low supersaturation are simultaneously present in the system, the dislocation-driven growth mode dominates the process, in which the step edges form at the later stage of the growth responsible for the formation of crown-like nanoplates.
Co-reporter:Liangbing Wang, Songtao Zhao, Chenxuan Liu, Chen Li, Xu Li, Hongliang Li, Youcheng Wang, Chao Ma, Zhenyu Li, and Jie Zeng
Nano Letters 2015 Volume 15(Issue 5) pp:2875-2880
Publication Date(Web):April 3, 2015
DOI:10.1021/nl5045132
Bimetallic Au75Pd25 nanocrystals with shapes of icosahedron and octahedron were synthesized by adding different amounts of iodide ions, and were employed as catalysts for solvent-free aerobic oxidation of cyclohexane. Although both icosahedrons and octahedrons were bounded by {111} facets, the turnover frequency number of Au75Pd25 icosahedrons reached 15 106 h–1, almost three times as high as that of Au75Pd25 octahedrons. The conversion of cyclohexane reached 28.1% after 48 h using Au75Pd25 icosahedrons, with the selectivity of 84.3% to cyclohexanone. Density functional theory calculations along with X-ray photoelectron spectroscopy examinations reveal that the excellent catalytic performance of AuPd icosahedrons could be ascribed to twin-induced strain and highly negative charge density of Au atoms on the surface.
Co-reporter:Xu Zhao; Sheng Chen; Zhicheng Fang; Jia Ding; Wei Sang; Youcheng Wang; Jin Zhao; Zhenmeng Peng
Journal of the American Chemical Society 2015 Volume 137(Issue 8) pp:2804-2807
Publication Date(Web):February 12, 2015
DOI:10.1021/ja511596c
Forming core–shell and alloy structures offers generally two ways to design efficient Pt-based catalysts for oxygen reduction reaction (ORR). Here, we combined these two strategies and invented a versatile aqueous route to synthesize octahedral Pd@Pt1.8Ni core–shell nanocrystals. The Pt/Ni atomic ratios in the resultant shells can be varied from 0.6 to 1.8, simply by changing the amounts of Pt and Ni precursors, with the other conditions unchanged. Experimental studies showed that the mass activities of as-prepared catalysts were 5 times higher than that of the commercial Pt/C. We believe that the ultrathin PtNi shells enclosed by {111} facets made it possible to reduce the Pt content while retaining the catalytic activity toward ORR. This strategy may be extended to the preparation of other multimetallic nanocrystals with shaped and ultrathin alloy shells, which is conducive to design highly active catalysts.
Co-reporter:Menglin Wang; Liangbing Wang; Hongliang Li; Wenpeng Du; Munir Ullah Khan; Songtao Zhao; Chao Ma; Zhenyu Li
Journal of the American Chemical Society 2015 Volume 137(Issue 44) pp:14027-14030
Publication Date(Web):October 24, 2015
DOI:10.1021/jacs.5b08289
Non-noble bimetallic nanocrystals (NCs) have been widely explored due to not only their low cost and abundant content in the Earth’s crust but also their outstanding performance in catalytic reactions. However, controllable synthesis of non-noble alloys remains a significant challenge. Here we report a facile synthesis of CuNi octahedra and nanocubes with controllable shapes and tunable compositions. Its success relies on the use of borane morpholine as a reducing agent, which upon decomposition generates a burst of H2 molecules to induce rapid formation of the nuclei. Specifically, octahedra switched to nanocubes with an increased amount of borane morpholine. In addition, the ratio of CuNi NCs could be facilely tuned by changing the molar ratio of both precursors. The obtained CuNi NCs exhibited high activity in aldehyde-alkyne-amine coupling reactions, and their performance is strongly facet- and composition-dependent due to the competition of the surface energy (enhanced by increasing the percent of Ni) and active sites (derived from Cu atoms).
Co-reporter:Sheng Chen;Hongyang Su;Youcheng Wang;Wenlong Wu; Jie Zeng
Angewandte Chemie International Edition 2015 Volume 54( Issue 1) pp:108-113
Publication Date(Web):
DOI:10.1002/anie.201408399
Abstract
Mastery over the structure of materials at nanoscale can effectively tailor and control their catalytic properties, enabling enhancement in both activity and durability. We report a size-controlled synthesis of novel Pt–Cu hierarchical trigonal bipyramid nanoframes (HTBNFs). The obtained nanocrystals looked like a trigonal bipyramid on the whole, composed of similar ordered frame structural units. By varying the amount of KI involved in the reaction, HTBNFs with variable sizes from 110 to 250 nm could be obtained. In addition, the structure of HTBNFs could be preserved only in a limited range of the Pt/Cu feeding ratio. Relative to the commercial Pt/C, these Pt–Cu HTBNFs with different Pt/Cu ratio exhibited enhanced electrocatalytic activity toward formic acid oxidation reaction as much as 5.5 times in specific activity and 2.1 times in mass activity. The excellent electrocatalytic activity and better durability are due to the unique structure of HTBNFs and probably synergetic effects between Pt and Cu.
Co-reporter:Awei Zhuang;Yuzhou Zhao;Xianli Liu;Mingrui Xu;Youcheng Wang
Nano Research 2015 Volume 8( Issue 1) pp:246-256
Publication Date(Web):2015 January
DOI:10.1007/s12274-014-0657-y
Co-reporter:Sheng Chen;Hongyang Su;Youcheng Wang;Wenlong Wu; Jie Zeng
Angewandte Chemie 2015 Volume 127( Issue 1) pp:110-115
Publication Date(Web):
DOI:10.1002/ange.201408399
Abstract
Mastery over the structure of materials at nanoscale can effectively tailor and control their catalytic properties, enabling enhancement in both activity and durability. We report a size-controlled synthesis of novel Pt–Cu hierarchical trigonal bipyramid nanoframes (HTBNFs). The obtained nanocrystals looked like a trigonal bipyramid on the whole, composed of similar ordered frame structural units. By varying the amount of KI involved in the reaction, HTBNFs with variable sizes from 110 to 250 nm could be obtained. In addition, the structure of HTBNFs could be preserved only in a limited range of the Pt/Cu feeding ratio. Relative to the commercial Pt/C, these Pt–Cu HTBNFs with different Pt/Cu ratio exhibited enhanced electrocatalytic activity toward formic acid oxidation reaction as much as 5.5 times in specific activity and 2.1 times in mass activity. The excellent electrocatalytic activity and better durability are due to the unique structure of HTBNFs and probably synergetic effects between Pt and Cu.
Co-reporter:Xianli Liu;Jinwei Xu;Zhicheng Fang;Lin Lin;Yu Qian;Youcheng Wang
Nano Research 2015 Volume 8( Issue 11) pp:3612-3620
Publication Date(Web):2015 November
DOI:10.1007/s12274-015-0861-4
Shape control has proven to be a powerful and versatile means of tailoring the properties of Bi2Se3 nanostructures for a wide variety of applications. Here, three different Bi2Se3 nanostructures, i.e., spiral-type nanoplates, smooth nanoplates, and dendritic nanostructures, were prepared by manipulating the supersaturation level in the synthetic system. This mechanism study indicated that, at low supersaturation, defects in the crystal growth could cause a step edge upon which Bi2Se3 particles were added continuously, leading to the formation of spiral-type nanoplates. At intermediate supersaturation, the aggregation of amorphous Bi2Se3 particles and subsequent recrystallization resulted in the formation of smooth nanoplates. Furthermore, at high supersaturation, polycrystalline Bi2Se3 cores formed initially, on which anisotropic growth of Bi2Se3 occurred. This work not only advances our understanding of the growth mechanism but also offers a new approach to control the morphology of Bi2Se3 nanostructures.
Co-reporter:Wei Sang, Tingting Zheng, Youcheng Wang, Xu Li, Xu Zhao, Jie Zeng, and J. G. Hou
Nano Letters 2014 Volume 14(Issue 11) pp:6666-6671
Publication Date(Web):October 13, 2014
DOI:10.1021/nl503343n
Metal–sulfide hybrid nanocrystals (HNCs) have been of great interest for their distinguished interfacial effect, which gives rise to unique catalytic properties. However, most of the reported metal–sulfide HNCs were synthesized via two-step approaches and few were fabricated based on the one-step strategies. Herein, we report a facile one-pot synthesis of CuPt–Cu2S, Pt–Cu2S HNCs, and CuPt nanocubes by simply changing the Pt precursor types. 1-Hexadecanethiol (HDT) was employed in this system to mediate the reduction of metal precursors and also as capping agent and sulfur source. Moreover, CuPd–Cu2S and Au–Cu2S HNCs were successfully prepared by using this one-step method. The catalytic properties of the obtained three nanocrystals were investigated in hydrogenation of cinnamaldehyde. Results show that CuPt–Cu2S HNCs exhibited the highest conversion rate and the highest selectivity toward hydrocinnamaldehyde while 3-phenyl-1-propanol was the only product over Pt–Cu2S HNCs.
Co-reporter:Awei Zhuang;Jia-Jun Li;You-Cheng Wang;Xin Wen;Yue Lin; Bin Xiang; Xiaoping Wang; Jie Zeng
Angewandte Chemie 2014 Volume 126( Issue 25) pp:6543-6547
Publication Date(Web):
DOI:10.1002/ange.201403530
Abstract
Bi2Se3 attracts intensive attention as a typical thermoelectric material and a promising topological insulator material. However, previously reported Bi2Se3 nanostructures are limited to nanoribbons and smooth nanoplates. Herein, we report the synthesis of spiral Bi2Se3 nanoplates and their screw-dislocation-driven (SDD) bidirectional growth process. Typical products showed a bipyramid-like shape with two sets of centrosymmetric helical fringes on the top and bottom faces. Other evidence for the unique structure and growth mode include herringbone contours, spiral arms, and hollow cores. Through the manipulation of kinetic factors, including the precursor concentration, the pH value, and the amount of reductant, we were able to tune the supersaturation in the regime of SDD to layer-by-layer growth. Nanoplates with preliminary dislocations were discovered in samples with an appropriate supersaturation value and employed for investigation of the SDD growth process.
Co-reporter:Dr. Wenshuai Chen;Qing Li;Youcheng Wang;Xin Yi; Jie Zeng; Haipeng Yu; Yixing Liu; Jian Li
ChemSusChem 2014 Volume 7( Issue 1) pp:
Publication Date(Web):
DOI:10.1002/cssc.201301337
Co-reporter:Dr. Wenshuai Chen;Qing Li;Youcheng Wang;Xin Yi; Jie Zeng; Haipeng Yu; Yixing Liu; Jian Li
ChemSusChem 2014 Volume 7( Issue 1) pp:154-161
Publication Date(Web):
DOI:10.1002/cssc.201300950
Abstract
This article describes the fabrication of nanocellulose fibers (NCFs) with different morphologies and surface properties from biomass resources as well as their self-aggregation into lightweight aerogels. By carefully modulating the nanofibrillation process, four types of NCFs could be readily fabricated, including long aggregated nanofiber bundles, long individualized nanofibers with surface C6-carboxylate groups, short aggregated nanofibers, and short individualized nanofibers with surface sulfate groups. Free-standing lightweight aerogels were obtained from the corresponding aqueous NCF suspensions through freeze-drying. The structure of the aerogels could be controlled by manipulating the type of NCFs and the concentration of their suspensions. A possible mechanism for the self-aggregation of NCFs into two- or three-dimensional aerogel nanostructures was further proposed. Owing to web-like structure, high porosity, and high surface reactivity, the NCF aerogels exhibited high mechanical flexibility and ductility, and excellent properties for water uptake, removal of dye pollutants, and the use as thermal insulation materials. The aerogels also displayed sound-adsorption capability at high frequencies.
Co-reporter:Awei Zhuang;Jia-Jun Li;You-Cheng Wang;Xin Wen;Yue Lin; Bin Xiang; Xiaoping Wang; Jie Zeng
Angewandte Chemie International Edition 2014 Volume 53( Issue 25) pp:6425-6429
Publication Date(Web):
DOI:10.1002/anie.201403530
Abstract
Bi2Se3 attracts intensive attention as a typical thermoelectric material and a promising topological insulator material. However, previously reported Bi2Se3 nanostructures are limited to nanoribbons and smooth nanoplates. Herein, we report the synthesis of spiral Bi2Se3 nanoplates and their screw-dislocation-driven (SDD) bidirectional growth process. Typical products showed a bipyramid-like shape with two sets of centrosymmetric helical fringes on the top and bottom faces. Other evidence for the unique structure and growth mode include herringbone contours, spiral arms, and hollow cores. Through the manipulation of kinetic factors, including the precursor concentration, the pH value, and the amount of reductant, we were able to tune the supersaturation in the regime of SDD to layer-by-layer growth. Nanoplates with preliminary dislocations were discovered in samples with an appropriate supersaturation value and employed for investigation of the SDD growth process.
Co-reporter:Liang-Bing Wang ; You-Cheng Wang ; Rong He ; Awei Zhuang ; Xiaoping Wang ; Jie Zeng ;J. G. Hou
Journal of the American Chemical Society 2013 Volume 135(Issue 4) pp:1272-1275
Publication Date(Web):January 14, 2013
DOI:10.1021/ja3120136
We report a rational design of CaHPO4-α-amylase hybrid nanobiocatalytic system based on allosteric effect and an explanation of the increase in catalytic activity when certain enzymes are immobilized in specific nanomaterials. Employing a calcification approach in aqueous solutions, we acquired such new nanobiocatalytic systems with three different morphologies, i.e., nanoflowers, nanoplates, and parallel hexahedrons. Through studying enzymatic performance of these systems and free α-amylase with/without Ca2+, we demonstrated how two factors, allosteric regulation and morphology of the as-synthesized nanostructures, predominantly influence enzymatic activity. Benefiting from both the allosteric modulation and its hierarchical structure, CaHPO4-α-amylase hybrid nanoflowers exhibited dramatically enhanced enzymatic activity. As a bonus, the new system we devised was found to enjoy higher stability and durability than free α-amylase plus Ca2+.
Co-reporter:Shan Liang, Xiao-Li Liu, Yue-Zhou Yang, Ya-Lan Wang, Jia-Hong Wang, Zhong-Jian Yang, Liang-Bing Wang, Shuang-Feng Jia, Xue-Feng Yu, Li Zhou, Jian-Bo Wang, Jie Zeng, Qu-Quan Wang, and Zhenyu Zhang
Nano Letters 2012 Volume 12(Issue 10) pp:5281-5286
Publication Date(Web):September 4, 2012
DOI:10.1021/nl3025505
This paper describes a facile method for synthesis of Au–AgCdSe hybrid nanorods with controlled morphologies and spatial distributions. The synthesis involved deposition of Ag tips at the ends of Au nanorod seeds, followed by selenization of the Ag tips and overgrowth of CdSe on these sites. By simply manipulating the pH value of the system, the AgCdSe could selectively grow at one end, at both the ends or on the side surface of a Au nanorod, generating a mike-like, dumbbell-like, or toothbrush-like hybrid nanorod, respectively. These three types of Au–AgCdSe hybrid nanorods displayed distinct localized surface plasmon resonance and photoluminescence properties, demonstrating an effective pathway for maneuvering the optical properties of nanocrystals.
Co-reporter:Yue Lin;Zhigang Geng;Hongbing Cai;Lu Ma;Jia Chen;Nan Pan;Xiaoping Wang
European Journal of Inorganic Chemistry 2012 Volume 2012( Issue 28) pp:4439-4444
Publication Date(Web):
DOI:10.1002/ejic.201200454
Abstract
We developed a ternary nanocomposite of graphene–TiO2–Fe3O4 (GTF) as a low-cost, recollectable, and stable photocatalyst for the degradation of organic dyes. The nanocomposite has been successfully prepared by successively growing TiO2 and Fe3O4 nanoparticles on the reduced graphene oxide (RGO). The as-synthesized GTF nanocomposite shows higher photocatalytic activity as compared with that of pure TiO2 nanoparticles and can be easily collected from water using a magnet. More importantly, benefiting from the presence of RGO, GTF can suppress the photodissolution behavior of Fe3O4 nanoparticles that usually occurrs in TiO2–Fe3O4 binary nanocomposites, rendering it a highly stable photocatalyst. Furthermore, the GTF nanocomposite works well in different pH environments and is capable of eliminating mixtures of various dyes. In addition, the GTF is also able to degrade the dyes under sunlight. These attractive features make the GTF nanocomposite a promising photocatalyst for practical use in wastewater treatment.
Co-reporter:Ruijie Huang, Zhongti Sun, Sheng Chen, Siyu Wu, Zeqi Shen, Xiaojun Wu and Jie Zeng
Chemical Communications 2017 - vol. 53(Issue 51) pp:NaN6925-6925
Publication Date(Web):2017/06/06
DOI:10.1039/C7CC03643D
Hierarchical metal nanostructures which exhibit an open structure and a high density of twin defects accessible to reactants hold great promise in catalysis. Here, we report a facile synthesis of Pt–Cu hierarchical quasi great dodecahedrons (HQGDs) which present 5-fold symmetry and are composed of multiple ordered branched units with a frame structure. HQGDs evolve from icosahedral seeds with multiple {111} twin planes, followed by the growth of higher-order branches. Owing to the unique frame structure associated with multiple twin defects, HQGDs showed much higher HER catalytic activity and better durability relative to commercial Pt/C.
Co-reporter:Xiaochen Shen, Yanbo Pan, Bin Liu, Jinlong Yang, Jie Zeng and Zhenmeng Peng
Physical Chemistry Chemical Physics 2017 - vol. 19(Issue 20) pp:NaN12632-12632
Publication Date(Web):2017/04/05
DOI:10.1039/C7CP01817G
The reaction mechanism and properties of a catalytic process are primarily determined by the interactions between reacting species and catalysts. However, the interactions are often challenging to be experimentally measured, especially for unstable intermediates. Therefore, it is of significant importance to establish an exact relationship between chemical–catalyst interactions and catalyst parameters, which will allow calculation of these interactions and thus advance their mechanistic understanding. Herein we report the description of adsorption energy on transition metals by considering both ionic bonding and covalent bonding contributions and introduce the work function as one additional responsible parameter. We find that the adsorption energy can be more accurately described using a two-dimensional (2D) polynomial model, which shows a significant improvement compared with the current adsorption energy–d-band center linear correlation. We also demonstrate the utilization of this new 2D polynomial model to calculate oxygen binding energy of different transition metals to help understand their catalytic properties in oxygen reduction reactions.
