ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
He-Qiang Chang,Guo-Hua Zhang,Kuo-Chih Chou
Electrochemical water splitting is considered a sustainable route for the hydrogen industry. In this work, Mo 2 C/MoC heterostructure supported on N -doped carbon (Mo 2 C/MoC@NC) was prepared via a carbonization strategy. For the product (Mo 2 C/MoC@NC-1-2) fabricated with a g-C 3 N 4 / ammonium molybdate tetrahydrate molar ratio of 1:2 at 700 °C under 10%CH 4 /H 2 atmosphere, a high stability and good HER activity with a η 10 of 113 mV in 1M KOH were achieved. To further enhance the catalytic performance of the synthesized Mo 2 C/MoC@NC, the phosphating strategy was proposed for the preparation of Mo 2 C/MoC/MoP heterostructure supported on N-doped carbon (Mo 2 C/MoC/MoP@NC). When the precursor Mo 2 C/MoC@NC-1-2 was phosphated at 650 °C with a heating rate of 5 °C min −1 and kept for 0 min, the as-synthesized Mo 2 C/MoC/MoP@NC-650-0 exhibits good HER catalytic activity with a pretty low η 10 of 78 mV, a j 0 of 0.398 mA cm −2 , and a Tafel slope of 52 mV dec −1 in 1M KOH. This good activity of HER can be ascribed to the N-doped carbon as substrate and the construction of transition metal-based heterostructures.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Changhai Liu,Lei Sun,Linlin Luo,Wenchang Wang,Huilong Dong,Zhidong Chen
Although nonprecious metal catalysts based on earth-abundant 3d transition metals (TMs) are regarded as promising substitutes for a noble metal electrocatalytic hydrogen evolution reaction (HER), their large-scale application is still inhibited by their inadequate activity and durability. Here, a facile method for nonprecious metal catalysts has been developed to prepare molybdenum carbide on nitrogen-doped carbon. By optimizing the Ni doping ratio, the Ni0.5@MoCx/NC exhibits the lowest overpotential for 10 mA cm–2 and superior stability in both acidic and alkaline media for HER application, outperforming most of the reported HER electrocatalysts. In addition, a theoretical simulation has also confirmed the possible mechanism for the synergistic effect with the regulative adsorption energy of hydrogen species with Ni doping and formation of a Mo2C/MoC heterojunction in the Ni0.5@MoCx/NC electrocatalyst. Therefore, this work provides a new avenue for designing two-dimensional nanostructures with an optimized electronic structure for promising TM HER electrocatalysts in a wide pH range.
研究领域:
电化学
·
材料科学
·
催化
·
能源材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 18
·8920-8926
·
IF 11.301
Ying Liu,Xiaorong Zhu,Qinghua Zhang,Tang Tang,Yun Zhang,Lin Gu,Yafei Li,Jianchun Bao,Zhihui Dai,Jin-Song Hu
The development of efficient and cost-effective electrocatalysts is essential for the electrochemical reduction of N2 to produce NH3 under ambient conditions. Herein, various well-dispersed Mo-based nanoparticles are selectively synthesized to reveal the influences of the compositions and hetero-interfaces on the performance for the N2 reduction reaction (NRR). Systematic experiments discovered that compared with single-component Mo2C or Mo nanoparticles, the heterostructured binary MoC/Mo2C and ternary Mo/MoC/Mo2C nanoparticles exhibit significantly enhanced NRR performance by creating abundant hetero-interfaces. Moreover, theoretical calculations reveal that the integration of metallic Mo with MoC/Mo2C appreciably reduces the energy demand for NH3 desorption, contributing to the enhanced NRR process. As a result, a remarkable NH3 yield rate of up to 20.4 μg h−1 mg−1 and a FE up to 18.9% can be achieved. These findings suggest that engineering crystalline phases and hetero-interfaces represents a new avenue for advancing the electrocatalytic performance of a NRR catalyst.
研究领域:
材料科学
·
电化学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
Qingtao Wang,Fangfang Mi,Jian Li,Yanxia Wu,Xiaozhong Zhou,Guofu Ma,Shufang Ren
Renewable hydrogen energy has been regarded as ideal green energy. There is an urgent need for efficient and stable non-noble metal electrocatalysts for hydrogen evolution reaction (HER). Molybdenum carbide (Mo x C) has excellent intrinsic activity and stability, which is expected as one of the ideal candidates to replace Pt. Herein, we report a facile Tungsten (W) doping method to regulate the crystal structure of Mo x C to generate a Mo 2 C-MoC heterostructure. It reduces the charge transfer resistance and regulates adsorption and desorption of hydrogen, thereby promoting the HER in alkaline solution. Besides, the carbon matrix not only increases the conductivity, but also protects the active site of W-Mo x C/C from agglomeration and deactivation due to high temperature. Under alkaline media, the W-Mo x C/C has improved HER catalytic activity. In 1 M KOH, an overpotential of 178 mV is required to reach a current density of 10 mA cm −2 , and the Tafel slope is 54.3 mV dec −1 . Moreover, it has a small charge transfer resistance and good stability. This work develops a multi-effect doping method that generates heterostructure and increases the active sites, which providing a new strategy for the performance regulation of other electrocatalysts.
研究领域:
材料科学
·
电催化
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Xiang Zou,Haitong Tang,Junzhi Li,Guichen Gao,Zhibing Geng,Liping Li,Guangshe Li
The electronic structure of molybdenum carbide closely resembles that of Pt, making it a promising candidate material for replacing noble metal catalysts . However, the primary challenge is the controlled and eco-friendly synthesis of molybdenum carbide. Herein, we developed a sustainable and controlled method for synthesizing a heterostructure catalyst for the electrocatalytic hydrogen evolution reaction (HER) using starch as the raw material. Through a hydrothermal redox reaction and subsequent temperature-programmed treatment under an inert atmosphere , the hexagonal Mo 2 C-cubic MoC heterostructure nanoparticles were dispersed on a carbon matrix. Our investigation into the synthesis process extensively covered the growth of MoO 2 nanocrystals and hydrochar during the hydrothermal redox reaction , as well as the phase evolution during the subsequent temperature-programmed treatment. Electrochemical assessments demonstrated the catalyst's remarkable efficiency for the hydrogen evolution reaction across both acidic and alkaline media, achieving a current density of 10 mA/cm 2 with an overpotential of 139.4 mV in 1 M KOH solution and 160.7 mV in 0.5 M H 2 SO 4 solution. Combining a series of electrochemical characterizations and applying the distribution of relaxation times (DRT) analysis to operando electrochemical impedance spectroscopy (EIS) data, the superior kinetic performance of the Mo 2 C–MoC/C was demonstrated, outperforming that of single-phase molybdenum carbide. Furthermore, the catalyst has demonstrated remarkable stability even at high current densities in both acidic and alkaline electrolytes , underscoring its potential as a cathode catalyst in both alkaline water electrolyzers and proton exchange membrane (PEM) electrolyzers.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
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