探讨Cu / Mo2C / Mo2N异质结对HER性能的影响,Catalysis Science & Technology

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探讨Cu / Mo2C / Mo2N异质结对HER性能的影响
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2020-02-14 , DOI: 10.1039/c9cy02526j
Rajinder Kumar _{1,

2,

3} , Zubair Ahmed _{1,

2,

3} , Harwinder Kaur _{1,

2,

3} , Chandan Bera _{1,

2,

3} , Vivek Bagchi _{1,

2,

3}

Affiliation

氢是最清洁的能源之一，可以解决许多问题，包括环境污染和化石燃料的消耗。氢释放反应（HER）是一种碳中和过程，可以减少地球大气中的碳含量。钼基固体是最流行的电催化剂之一，并已广泛地探索用于HER工艺以替代铂。本文中，我们报道了一种由碳化钼，氮化钼和元素铜组成的纳米结构电催化剂（CuMoCat），在复合物中形成异质结。将铜掺杂到碳化钼/氮化物复合物中，不仅有助于降低过电位，而且还可以使催化剂在高电流密度下运行。^-2用33毫伏分解的塔菲尔斜率值^-1和节目的在酸性介质中3000次循环优异的稳定性。理论研究表明，Cu掺杂会改变催化剂的电子性能，从而改善析氢反应过程中催化剂表面上氢的整体吸附和解吸。CuMoCat的'Mo'和'N'氢吸附位点的自由能图显示了自由能的移动，相对于未掺杂催化剂的Mo / N位点，这些自由能对HER更有利。

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Probing into the effect of heterojunctions between Cu/Mo2C/Mo2N on HER performance

Hydrogen is one of the cleanest forms of energy and can solve several issues, including environmental pollution and depletion of fossil fuels. The hydrogen evolution reaction (HER), being a carbon-neutral process, can reduce the amount of carbon in the earth's atmosphere. Molybdenum based solids are among the most popular electrocatalysts, and have been explored extensively for HER processes as an alternative to platinum. Herein, we report a nanostructured electrocatalyst (CuMoCat) consisting of molybdenum carbide, molybdenum nitride, and elemental copper, forming a heterojunction within the composite. Copper doping into a molybdenum carbide/nitride composite not only facilitates the lowering of the overpotential but also enables the catalyst to perform at high current density. CuMoCat exhibits an overpotential of 82 mV for attaining a current density of 10 mA cm⁻² with a Tafel slope value of 33 mV dec⁻¹ and shows excellent stability of 3000 cycles in acidic media. A theoretical study reveals that Cu doping brings a change in the electronic properties of the catalyst, which improves the overall adsorption and desorption of hydrogen on the catalyst surface during the hydrogen evolution reaction. The free energy diagram for the ‘Mo’ and ‘N’ hydrogen adsorption sites of CuMoCat shows a shift of free energy making these more favourable for the HER with respect to the Mo/N sites of the un-doped catalyst.

更新日期：2020-02-14

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