Wet-chemistry synthesis of ultrasmall α-MoC1-x nanoparticles and rGO/α-MoC1-x composite and its evaluation as electrocatalysts for hydrogen evolution reaction

Abstract

Ultrasmall molybdenum carbide α−MoC1−x nanoparticles (1.6 nm) and the hybrid material rGO/α−MoC1−x supported in reduced graphene oxide (rGO) were synthesized by a one-pot oleylamine-mediated route at low-temperature (613 K). They were evaluated as electrocatalysts for the hydrogen evolution reaction (HER) in the acid medium after surface cleaning with an ethanol-acetic acid solution. The electrocatalysts were also thermal treated (N2 flow, 773 K/30 min) and compared with untreated ones. Quite large HER activity was observed for the α−MoC1−x compared with the rGO/α−MoC1−x and rGO/α−MoC1−x−773. In addition, after cycling, all catalysts showed considerable performance improvement assigned to removing residual oleylamine molecules from the electrocatalyst’s surface. Compared to the unsupported sample, the lower catalytic activity in the supported materials was attributed to the ultrasmall carbide nanoparticles oxidation increases. The route is simple, with low costs and energy consumption, showing a high potential to develop efficient electrocatalysts for HER.