Synergy of rare earth single atoms and Pt nanoclusters@N-doped carbon for improved alkaline hydrogen evolution

Abstract

The sluggish water dissociation kinetics and low stability of Pt nanocluster (Pt_NC)-based electrocatalysts severely restrict the alkaline hydrogen evolution reaction (HER). By integrating the electron-buffer functionality of rare earth single atoms (RE_SAs: Ce, Pr, Sm, Gd) dispersed on N-doped carbon (NDC) with Pt_NCs, a novel catalyst Pt_NCs-RE_SAs@NDC has been developed. The RE → Pt electron redistribution through the constructed Pt∩N∩Pr interfacial electron bridge: i) makes Pt_NCs electron-rich and RE_SAs electron-deficient, which favors adsorption of H_ads and OH_ads, respectively, and ii) increases the covalency of the Pt–N bond, which improves stability by reinforcing the Pt_NCs-substrate interaction. Significantly boosted high mass activity (25.4 A·mg_Pt⁻¹ at an overpotential of 100 mV), with only 10% Pt loading of the commercial Pt/C and outstanding operational stability (runs stably at 500 mA·cm⁻² for 500 h in an alkaline anion exchange membrane water electrolyzer) are realized by integrating the unique electronic features of RE_SAs, e.g., Pt_NCs-Pr_SAs@NDC. These advancements demonstrate the great potential of RE_SAs for highly efficient HER.