N-doped carbon-wrapped MoxC heterophase sheets for high-efficiency electrochemical hydrogen production

Advancement of non-precious-metal catalysts for hydrogen evolution reactions (HER) with both prominent activity and excellent stability has been becoming an ongoing challenge in the following decades. Herein, N-doped carbon-wrapped molybdenum carbide heterophase (γ-MoC and β-Mo2C) sheets (N-MoxC@C HSs) were prepared by a facile chemical vapor reduction (CVR) procedure and following calcination at desired temperatures. The best HER electrocatalytic activity of N-MoxC@C HSs was detailedly examined in 0.5 M H2SO4, which exhibited a small overpotential of 172 mV (10 mA cm−2) with a Tafel slope of only 60 mV dec−1 and durability. The improved HER activities and catalytic stability were due to heterocrystal MoxC, nitrogen doping, and carbon coating. Particularly, this study effectively combined the respective advantages of both γ-MoC and β-Mo2C via the interface effect and matched polarity of hydrogen adsorption.