Boosting hydrogen evolution kinetics of self-supported MoC-Mo2C heterojunction electrode by platinum decoration.

Molybdenum carbide-based hydrogen evolution reaction (HER) electrocatalysts have attracted widespread attention with their low cost and relatively high catalytic activity. Despite the significant progress made in tuning the morphology and structure, the intrinsic catalytic activity of molybdenum carbide awaits further improvement. Herein, a Pt-decorated self-supported MoC-Mo 2 C electrode with super-intrinsic HER catalytic activity is prepared by a simple adsorption-electroreduction method. The HER performance is improved with increasing the loading of Pt. The optimal MoC-Mo 2 C-Pt heterojunction electrode has a low overpotential of 10 mA cm−2 (58 mV in H 2 SO 4 , 82 mV in KOH) and small Tafel slope (24 mV dec−1 in H 2 SO 4, 29 mV dec−1 in KOH), which is reduced to 0.45–0.5, 0.7–0.8, and 0.4–0.7 times of pristine MoC-Mo 2 C, Pt foil, and commercial Pt/C (2 mg cm−2), respectively. The improved HER catalysis is attributed to the rapid dissociation of water on MoC-Mo 2 C and efficient desorption of hydrogen on Pt. Therefore, decorating carbides with Pt is an effective way to design HER catalysts with enhanced catalytic activities in a wide pH range. [ABSTRACT FROM AUTHOR]