Efficient hydrogen production on MoNi4 electrocatalysts with fast water dissociation kinetics

By Jian Zhang, Tao Wang, Pan Liu, Z. Liao, Shaohua Liu, Xiaodong Zhuang, Mingwei Chen, E. Zschech, Xinliang Feng. Nature Communications, 2017

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Various platinum-free electrocatalysts have been explored for hydrogen evolution reaction in acidic solutions. However, in economical water-alkali electrolysers, sluggish water dissociation kinetics (Volmer step) on platinum-free electrocatalysts results in poor hydrogen-production activities. Here we report a MoNi4 electrocatalyst supported by MoO2 cuboids on nickel foam (MoNi4/MoO2@Ni), which is constructed by controlling the outward diffusion of nickel atoms on annealing precursor NiMoO4 cuboids on nickel foam. Experimental and theoretical results confirm that a rapid Tafel-step-decided hydrogen evolution proceeds on MoNi4 electrocatalyst. As a result, the MoNi4 electrocatalyst exhibits zero onset overpotential, an overpotential of 15 mV at 10 mA cm−2 and a low Tafel slope of 30 mV per decade in 1 M potassium hydroxide electrolyte, which are comparable to the results for platinum and superior to those for state-of-the-art platinum-free electrocatalysts. Benefiting from its scalable preparation and stability, the MoNi4 electrocatalyst is promising for practical water-alkali electrolysers. In water-alkali electrolyzers, sluggish water dissociation kinetics on platinum-free electrocatalysts result in poor hydrogen-production activities. Here the authors report a MoNi4electrocatalyst which reduces the kinetic energy barrier of water dissociation, leading to improved hydrogen-production performance.

Subfields: Mechanical Engineering, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/4115c3ffbeb6672356f02e0526986435116c8472