High Surface Area Metal Carbide Aerogels as Durable Catalyst for the Hydrogen Evolution Reaction

Abstract

Electrolyzers’ technologies are essential for the Hydrogen Economy scheme, and in order to drive the hydrogen production price down, their lifetime need to be extended. One important parameter that has not been given enough attention in this context is catalyst durability. In this work, a durable platinum-group metal-free catalyst was developed for hydrogen evolution reaction based on porous, high-surface area molybdenum carbide aerogel. Molybdenum oxide aerogel was synthesized by sol–gel method and carburized by methane-treatment. A three-dimensional molybdenum carbide network was obtained by reacting molybdenum oxide aerogel with CH4/H2 mixture at 700°C. Surface area measurement confirmed a substantial increase in the volume of micropores in the transition from oxide to carbide. The carbide aerogel has low density (<0.4 g/ml) with relatively high surface area of 109 m2/g (reduced from 188 m2/g after methane treatment). The molybdenum carbide aerogel shows remarkable durability compared to Pt/C catalyst, with only 10 mV overpotential shift vs. 100 mV for Pt/C after stability test.