Small
·
2019
·Vol. 15
·期 12
·1805474
·
IF 10.856
Yi Jiang,Xingqiao Wu,Yucong Yan,Sai Luo,Xiao Li,Jingbo Huang,Hui Zhang,Deren Yang
Developing an efficient electrocatalyst for the hydrogen evolution reaction (HER) working in both acidic and alkaline solutions is highly desirable, but still remains challenging. Here, Pt x Ni ultrathin nanowires (NWs) with tunable compositions ( x = 1.42, 3.21, 5.67) are in situ grown on MXenes (Ti 3 C 2 nanosheets), serving as electrocatalysts toward HER. Such Pt x Ni@Ti 3 C 2 electrocatalysts exhibit excellent HER performance in both acidic and alkaline solutions, with the Pt 3.21 Ni@Ti 3 C 2 being the best one. Specifically, Pt 3.21 Ni@Ti 3 C 2 achieves record-breaking performance in terms of lowest overpotential (18.55 mV) and smallest Tafel slope (13.37 mV dec −1 ) for HER in acidic media to date. Theory calculations and X-ray photoelectron spectroscopy analyses demonstrate that the coupling of MXenes with the NWs not only approaches the Gibbs free energy for hydrogen adsorption close to zero through the electron transfer between them in acidic media, but also provides additional active sites for water dissociation in alkaline solution, both of them being beneficial to the HER performance.
研究领域:
材料科学
·
电化学
·
纳米催化
·
能源材料
·
物理化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
M.Y. Gao,C. Yang,Q.B. Zhang,Y.W. Yu,Y.X. Hua,Y. Li,P. Dong
Porous Ni-Cu alloy films composed of nanosheets are directly fabricated on Cu substrate using a facile potentiostatic electrodeposition approach from a 1:2 choline chloride-ethylene glycol eutectic solvent (ethaline) containing nickel chloride and copper chloride. Electrochemical co-deposition of Ni-Cu alloy in ethaline is found to be thermodynamically favorable in comparison to conventional aqueous solutions. The deposition process occurs via an instantaneous nucleation and growth of nanoparticles at the initial stage and develops vertically to form nanoporous structures arrayed with nanosheets over deposition time . The as-prepared porous Ni-Cu alloy nanosheet arrays exhibit enhanced electrocatalytic activity for the hydrogen evolution reaction (HER) in alkaline media , which displays a small Tafel slope of 57.2 mV dec −1 with a low onset potential of −48 mV vs. RHE at an optimal condition. It requires small overpotentials of −128 and −150 mV to drive catalytic current densities of 10 and 20 mA cm −2 , respectively. This facile electrodeposition method performed in ethaline provides an efficient way to fabricate porous Ni-based alloy nanosheets directly on a current collector, which is a promising technology for the synthesis of earth-abundant HER electrocatalysts .
研究领域:
电催化
·
材料科学
·
能源化学
·
纳米材料
·
电化学
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2023
·
IF 3
Jiaxin Fu,Jin Hu,Yamin Lv,Lidan Miao,Kaizhao Wang,Jiale Wu,Kaijun Wang,Weijun Zhang
Gallium oxide (Ga 2 O 3 ), a promising semiconductor material, has attracted significant attention in recent years. This study focuses on a method for rapidly obtaining high-purity Ga 2 O 3 through the one-step hydrolysis of gallium in an alkaline environment to address the challenges of complex experimental equipment and the high-pressure condition of the traditional method. Uniformly dispersed rod-like GaOOH with a length of 2 µm is prepared using a 5 mM polyvinylpyrrolidone solution. Additionally, Ga 2 O 3 (500 °C α-Ga 2 O 3 and 800 °C β-Ga 2 O 3 ) with different crystal forms is prepared by calcinating GaOOH at different temperatures. Compared with conventional methods, this approach offers a fast, safe, and cheap process for preparing high-purity Ga 2 O 3 .
研究领域:
材料科学
·
无机化学
·
半导体材料
·
纳米材料
·
功能材料
✓ 已验证
DOI
高影响因子
FUEL
·
2018
·
IF 4.908
Yu-hong Qin,Min-min Feng,Zi-bing Zhao,Stanislav V. Vassilev,Jie Feng,Christina G. Vassileva,Wen-ying Li
The ash fusion process of Jincheng anthracite ash, rice straw ash and coal-biomass ashes with different rice straw ash addition ratios during co-gasification under CO 2 atmosphere was elucidated by the ash fusion test, chemical analyses, optical heating stage microscopy (OHSM), X-ray diffraction and scanning electron microscopy equipped with energy-dispersive X-ray analyzer. Results showed that the initial sintering and initial melting temperatures of coal-biomass ashes observed by OHSM decreased with the addition of rice straw ash. The deformation temperatures determined by the ash fusion test were close to the initial melting temperatures. The biomass ash addition to coal ash introduced excessive amounts of alkaline compounds in the ash mixtures that led to lower initial temperatures of liquid phase formation. The ash fusion behavior of coal-biomass ashes with a rice straw ash addition ≤3 wt% was similar to that of coal ash and fits to the “softening-melting” ash fusion mechanism. In contrast, the ash fusion behavior of coal-biomass ashes with a greater addition of rice straw ash (>3 wt%) experienced dramatic changes at lower temperature and fits to the ‘‘melting-dissolution’’ ash fusion mechanism.
研究领域:
燃料化学
·
能源工程
·
热化学转化
·
燃烧学
·
灰化学
✓ 已验证
DOI
高影响因子
Advanced Materials Interfaces
·
2018
·Vol. 5
·期 15
·1800515
·
IF 4.834
Lingxia Zheng,Wangwang Hu,Xuwei Shu,Huajun Zheng,Xiaosheng Fang
Cobalt phosphides based materials are considered as promising electrocatalysts for the hydrogen evolution reaction (HER). The catalytic performance can be further enhanced by improving the intrinsic catalytic activity, exposing more active sites and coupling with conductive support. Herein, a novel electrocatalyst based on nitrogen doped reduced graphene oxides decorates with uniformly distributed CoP x nanoparticles with a suitable P/Co ratio ( x = 1.7) via a facile and mild condition. The optimized composite (CoP x /N-rGO) exhibits superior electrocatalytic HER activities with a low overpotential of 104 mV (at 10 mA cm −2 ), a small Tafel slope of 65 mV dec −1 , and long-term stability in the alkaline media, comparable to the performance of other HER electrocatalysts. The remarkable HER performance can be ascribed to the good electrical conductivity of rGO and extra active sites created by nitrogen doping. In addition, the ultrafine nanostructure (average particle size ≈4 nm) and well-dispersed CoP x nanoparticles also help expose more active sites for electrocatalytic reactions, largely hindering the agglomeration and exfoliation. This work provides a versatile route on the design of multifunctional composite materials for renewable energy research with low cost and high activity.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源化学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Mingyuan Chen,Yaxin Lv,Peilin Wu,Liuyan Dong,Xingquan He,Lili Cui
To obtain highly active electrocatalyst for the whole electrochemical water splitting is of importance to generate hydrogen. Co(OH) 2 is used as electrocatalyst towards OER, however, the performance can be improved further. Usually, to construct the interface and adjust the electronic environment of electrocatalysts are regarded as powerful ways to improve the activity. Herein, CeO 2 -Co(OH) 2 sheets supported on copper foam (CF) are fabricated by electrodeposition method. The morphology and the electron structure of metals are adjusted by changing the molar ratio of Co to Ce, thus, resulting in different electrocatalytic activity. The optimal hybrids of CeO 2 -Co(OH) 2 exhibits lower overpotentials of 188, 269 mV to reach 10 mA cm −2 towards HER and OER, respectively, and good stability. Notably, it is found that the electroactivity is extremely superior to that of bare CF as well as the counterparts in the literature. Also, we try to employ M(OH) 2 (M = Fe, Ni) to substitute Co(OH) 2 to investigate the effect of species of hydroxides on the electron interaction between CeO 2 and hydroxides, the XPS results indicate that Ce and Co shows stronger electron interaction compared to other two control hydroxides. As electrocatalysts for alkaline full water splitting, CeO 2 -Co(OH) 2 requires a cell voltage of 1.62 V to drive 10 mA cm −2 . Experimental results prove the advantages of the electron engineering and morphology control.
研究领域:
材料科学
·
电化学
·
能源化学
·
纳米材料
·
催化化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
K. Huang,K. Bi,J.C. Xu,C. Liang,S. Lin,W.J. Wang,T.Z. Yang,Y.X. Du,R. Zhang,H.J. Yang,D.Y. Fan,Y.G. Wang,M. Lei
Novel nanocomposites of spherical graphite-carbon encased tungsten carbide (GC-WC) are synthesized by solid state reaction with melamine and WO 3 as precursors under N 2 atmosphere. The diameters of the GC-WC composites range from 50 to 200 nm and the WC nanoparticles inside with an average size of ca. 15 nm distribute uniformly. The characterization results indicate that the GC-WC is composed of few layers of graphite carbon and WC nanoparticles with high crystallization and purity. Moreover, the electrocatalytic performance of GC-WC for the oxygen reduction reaction (ORR) in alkaline medium is further investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with or without 3 M methanol. The results show that GC-WC has a considerable performance for ORR in the view of activity, stability and methanol tolerance, which may further used as proper supports for noble-metal based ORR catalysts in alkaline fuel cell . The synergetic interaction between the carbide nanoparticles and graphite carbon, which means that the surface graphite carbon layers are activated by WC nanoparticles for ORR and in turn protect inner WC from highly oxidizing environments has also been verified.
研究领域:
材料科学
·
纳米科技
·
电化学
·
能源材料
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Xinming Du,Zhe Wang,Wenchang Liu,Jingmei Xu,Zhaoyu Chen,Chunmei Wang
A series of phenolphthalein-based poly (arylene ether ketone) (PEK) copolymer are synthesized to prepare anion exchange membranes (AEMs). The ion group 1-vinyl imidazole is introduced on the unit of phenolphthalein-based as a hydrophilic segment and cross-linking agent. The structure of resulting membranes was investigated by 1 H NMR and FT-IR. The well-defined microphase-separated structures were verified by TEM and SAXS profiles. The cross-linked membrane of ImPEK-0.4 exhibits high hydroxide conductivity (0.0836 S/cm, at 80 °C), excellent mechanical performance (69.6 MPa) and the maximum swelling ratio is only 7.95% at 80 °C. Furthermore, the excellent alkaline stability is demonstrated by immersing the prepared membrane in 1 M NaOH at 40 °C for 400 h. The ionic conductivity is still high to 0.0381 S/cm for ImPEK-0.4. These results indicate that combining phase separation architecture and crosslinking may possess potential applications for alkaline fuel cells (AFCs).
研究领域:
高分子材料科学
·
电化学能源材料
·
燃料电池技术
·
膜分离工程
·
聚合物化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2015
·Vol. 36
·期 10
·1726-1732
·
IF 1.964
Huanhui Chen,Xiaoci Li,Guoqing Zhao,Hongbo Gu,Zhirong Zhu
The side-chain alkylation of toluene represents a novel, environmentally friendly, and low cost route for the production of styrene . However, the yield of styrene produced in this way is currently low, and the mechanism responsible for the side-chain alkylation of toluene is poorly understood. Furthermore, the reason for the higher catalytic efficiency of CsX over NaX and KX remains unclear. In this work, the free radical mechanism of the side-chain alkylation of toluene over basic zeolite X has been elucidated using quantum chemical calculations , together with isotope tracing experiments and the reaction between p -nitrotoluene and methanol. The adsorption isotherm of methanol showed that Cs + ions could block methanol from accessing the β-cage, which is where the side-chain alkylation reaction occurred. Furthermore, the H–D exchange results between toluene and deuterated toluene (C 6 D 5 CD 3 ) showed that CsX was more efficient as a catalyst than KX for the conversion of toluene to the corresponding benzyl radical (C 6 H 5 CH 2 • ). These two results therefore explain the higher catalytic activity of CsX towards side-chain alkylation than KX. Based on the free radical mechanism, the selectivity of styrene could be increased from 17.4% to 59.4% using CO 2 as carrier gas instead of N 2 .
研究领域:
物理化学
·
催化化学
·
材料化学
·
反应机理
·
理论化学
·
能源化学
·
环境化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Xiaozhen Chen,Ji Qi,Pan Wang,Chuang Li,Xiao Chen,Changhai Liang
Herein, PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness are synthesized via a polyvinyl alcohol (PVA) involved approach and used for hydrogen evolution reaction (HER). The average crystallite size of the PVA protected nMo 2 CN nanospheres (6.1 nm) is one third of that of the PVA-Mo 2 C/Mo 2 N without PVA protection (17.9 nm). At 10 mA cm −2 current density, the as-synthesized PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness exhibit HER overpotentials of 132 mV and 142 mV with corresponding Tafel slope of 51.8 mV dec −1 and 50.4 mV dec −1 in acid and alkaline medium, respectively. This high apparent activity can be attributed to the high intrinsic activity originated from the adjacent surface active sites of Mo 2 C and Mo 2 N as well as the large ECSA of PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness.
研究领域:
材料科学
·
电化学
·
纳米催化
·
能源化学
·
表面科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 78
·41398-41410
·
IF 3.708
Xiuhua Li,Jinxiong Tao,Guanghui Nie,Liuchan Wang,Liuhong Li,Shijun Liao
A series of cross-linked multiblock copoly(arylene ether sulfone) ionomer/nano-ZrO2 (CLQCPAES/nano-ZrO2) composite anion exchange membranes were prepared via block copolymerization, bromomethylation, ultrasonication blending, self-crosslinking, quaternization and alkalization. The structure, and the surface and cross section morphology of the CLQCPAES/nano-ZrO2 composite membranes were characterized by solubility tests, FT-IR, XRD and SEM analyses. The combination of the determined results revealed that the CLQCPAES/nano-ZrO2 composite membranes are a complex cross-linking networks of hydrophobic domains/hydrophilic domains/nano-ZrO2 with a clear zonal distribution of uniform nano-sized particles in the hydrophilic domains, when the nano-filler loading was below 7.5%. Basic performances of the CLQCPAES/nano-ZrO2 composite membranes were assessed to investigate their application in fuel cells in terms of the water uptake, swelling ratio, ion exchange capacity (IEC), hydroxide conductivity, thermal and mechanical properties, and alkaline stability. The modification of anion exchange membranes with multiblock ionomer structures, the use of a cross-linking technique and the introduction of nano-ZrO2 particles greatly enhanced the water uptake, hydroxide conductivity, mechanical properties and alkaline stability of the composite membranes. In particular, the CLQCPAES/7.5%ZrO2 membrane with an IEC value of 1.23 mmol g−1 exhibited the best comprehensive properties and constitutes a good potential candidate for an anion exchange membrane to be used in AEMFCs.
研究领域:
高分子材料科学
·
电化学
·
能源材料
·
膜科学与技术
·
燃料电池
·
纳米复合材料
·
功能高分子
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2022
·
IF 9.794
Zhengjian Li,Sian Chen,Liting Cui,Haining Wang,Shanfu Lu,Yan Xiang
The acidic-alkaline interface of a bipolar membrane fuel cell (BPMFC) is the place to generate water, which significantly affect the output performance of BPMFC by regulating the water distribution due to the ion conductivity and oxygen reduction reaction (ORR) kinetics in cathode. To investigate the influence of water diffusivity ( D w ) on the water distribution, four alkaline polymer electrolytes with different D w is selected as anion exchange membrane or alkaline electrolyte ionomer to assemble BPMFCs. A combined experimental and simulated study reveals the positive correlation relationship of D w to the water distribution and performance of BPMFC. By increasing the D w of the alkaline polymer electrolytes, the interfacial-generated water amount can be increased and promptly transport to the cathode, thereby satisfying the ion conductivity and increasing the ORR kinetics, and breakthrough the peak power density of the BPMFC with 1.06 W cm −2 without humidification .
研究领域:
电化学
·
能源材料
·
燃料电池
·
高分子科学
·
界面科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）