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 (Mo 2 C/W 2 C) by carbonization with CH 4 /H 2 at 800 °C showing excellent HER activity, fast kinetics and electrochemical stability in both alkaline and acidic electrolytes. Mo 2 C/W 2 C requires only 140 and 132 mV overpotentials to reach catalytic current density of 10 mA cm−2 in 0.5 M H 2 SO 4 and 1 M KOH electrolyte, respectively. Tafel slope is as low as 51 and 76 mV dec−1 in 0.5 M H 2 SO 4 and 1 M KOH comparable to the benchmarked Pt/C. Moreover, Mo 2 C/W 2 C 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. Image 1 • Mo 2 C/W 2 C heterogeneous electrocatalyst is successfully synthesized. • The overpotential is 140 mV for Mo 2 C/W 2 C to deliver 10 mA cm−2 in acidic medium. • Mo 2 C/W 2 C requires 132 mV overpotential to reach 10 mA cm−2 in alkaline medium. [ABSTRACT FROM AUTHOR]