Construction of Mo2C/W2C heterogeneous electrocatalyst for efficient hydrogen evolution reaction

Constructing high-performance catalyst for hydrogen evolution reaction (HER) is the effective way to eliminate energy crisis. Reasonable engineering of heterointerfaces can effectively create more active sites and promote electron transfer resulting in improvement in the catalytic activity. In this work, we synthesize the well-defined molybdenum carbides and tungsten carbides nano-heterostructure (Mo2C/W2C) by carbonization with CH4/H-2 at 800 degrees C showing excellent HER activity, fast kinetics and electrochemical stability in both alkaline and acidic electrolytes. Mo2C/W2C requires only 140 and 132 mV over-potentials to reach catalytic current density of 10 mA cm(-2) in 0.5 M H2SO4 and 1 M KOH electrolyte, respectively. Tafel slope is as low as 51 and 76 mV dec(-1) in 0.5 M H2SO4 and 1 M KOH comparable to the benchmarked Pt/C. Moreover, Mo2C/W2C exhibits a superior stability with slight deterioration in HER performance after 5000 potential cycles. This work elucidates that the rational construction of heterointerfaces is favorable for design of efficient non-noble metal electrocatalyst for HER catalysis. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.