Ultralow-loading Pt single atoms anchored on N-doped carbon-encapsulated Mo2C microspheres for efficient hydrogen evolution

Abstract

Platinum (Pt)-based materials continue to serve as the benchmark electrocatalysts for the hydrogen evolution reaction (HER), yet their large-scale application is limited by the inherent scarcity and prohibitive cost of platinum. Herein, we develop a Pt-based single atom catalyst comprising Pt atoms anchored in N-doped carbon (NC) encapsulated onto molybdenum carbide (Mo₂C) microspheres. Structural analyses reveal an ultra-low Pt loading of 0.156 wt%, characterized by Pt–N₄ configurations. Kinetic measurements show that the optimized Pt-NC@Mo₂C exhibits exceptional HER performance with an overpotential of 37 mV at 10 mA cm⁻² and a Tafel slope of 40 mV dec⁻¹ in acidic solution, outperforming the commercial Pt/C (20 wt%) and most reported Pt-based catalysts. Experimental and theoretical studies demonstrated that the NC layer bridges the Pt atom and Mo₂C, which not only stabilizes atomic Pt active sites but also modulates their electronic structures through electron transfer from Pt to Mo₂C. This unique composite nanostructure optimizes and facilitates the adsorption of H* intermediates on the Pt-NC@Mo₂C, thereby enhancing its HER performance.