Transition Metal Carbide Electrocatalysts (WC, W₂C, and Mo₂C) Compared to Platinum in a Solid Acid Electrolysis Cell

The prospect of finding materials that perform like platinum group metals for water electrolysis under acidic conditions is an interesting subject with transition metal carbides. The present work focuses in this connection on hydrogen evolution reaction (HER) materials consisting of pure WC, W₂C, and Mo₂C in search for comparable materials to platinum under hydrothermal conditions (240 °C, 28 bar overpressure) in a gas-phase solid-acid electrolyzer. Phase characterizations and electrical conductivity measurements accompany the synthesis and implementation of the electrocatalysts. Special attention is given to the tungsten carbide species showing semi-conducting behavior with different dominating charge carrier types, apparently associated with the carbon content of the different carbide phases. Their electrocatalytic performance is compared to a high surface area platinum catalyst, where W₂C stands out for having the highest activity after platinum. The extrapolated temperature dependence activity of the W₂C indicates that it might surpass platinum at temperatures above 480 °C. This identifies W₂C as the most promising transition metal carbide alternative for platinum under these conditions.