Boosting Alkaline Hydrogen Evolution Activity of Pt Catalysts Using Mesoporous α-MoC1-x Support

Abstract

Inferior reaction kinetics of Pt catalysts for the alkaline hydrogen evolution reaction (HER) than acidic HER remains a challenge in water-alkali electrolyzers, which originates from an additional water dissociation step involved in the alkaline HER. In this presentation, we show that alkaline HER activity can be promoted by using Pt nanoparticles (NPs) supported on mesoporous α-MoC1-x (Pt/MMC) catalyst. In this catalyst, α-MoC1-x phase enables enhanced water dissociation capability while the mesoporous structure endows high surface area and efficient mass transport. In addition, X-ray absorption near edge structure and X-ray photoelectron spectroscopy revealed the electronic metal-support interaction (EMSI) between Pt NPs and MMC, which results in an electron transfer from MMC to Pt NPs adjusting the binding energy of proton on the Pt NPs to an optimized level. As a result, the Pt/MMC catalyst showed superior alkaline HER activity to Pt NPs supported on particulate α-MoC1-x or β-Mo2C, and exhibited 1.6- and 1.5-fold higher mass and specific activity than commercial Pt/C with the same Pt loading.