3D Metal Carbide Aerogel Network as a Stable Catalyst for the Hydrogen Evolution Reaction

Electrolyzer technologies are essential for the Hydrogen Economy scheme, and in order to drive the hydrogen production price down, their lifetimes 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 the hydrogen evolution reaction based on a porous, high-surface area molybdenum carbide aerogel. The molybdenum oxide aerogel was synthesized by a sol–gel method and carburized by methane treatment. A three-dimensional molybdenum carbide network was obtained by reacting the molybdenum oxide aerogel with a 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 a relatively high surface area of 109 m2/g (reduced from 188 m2/g after methane treatment). The molybdenum carbide aerogel shows remarkable stability compared to the Pt/C catalyst, with only a 10 mV overpotential shift vs 100 mV for Pt/C after stability tests.