In-situ construction of Mo2C-MoC heterostructure on Ni foam for efficient hydrogen evolution in alkaline media

Herein, a composite Mo2C-MoC heterostructured electrocatalyst is directly grown on Ni foam (NF) via the simple one-step annealing of MoCl5, urea, and NF under a flow of N2 at various temperatures for use in the hydrogen evolution reaction (HER). In the proposed synthetic method, the ratio of Mo2+ and Mo3+ in the Mo2C-MoC heterostructure, along with the HER performance, is greatly affected by the annealing temperature. In particular, the Mo2C-MoC/NF catalyst prepared at 650 degrees C exhibits a superior HER performance, with small overpotentials of 28.6 and 119.7 mV at 10 and 100 mA cm-2, respectively, along with great stability for 50 h in 1 M KOH. Notably, this is among the best performance results for recently reported molybdenum carbide-based catalysts. This is attributed to the interplay between the Mo2C-MoC heterostructure and the NF, whereby the former provides active sites by optimizing the hydrogen binding energy, while the latter provides a large surface area and high electrical conductivity. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.