A conjugated coordination polymer enables efficient proton supply on the platinum surface for alkaline hydrogen evolution electrocatalysis

Abstract

Developing a high-performance alkaline hydrogen evolution reaction (HER) catalyst is of great significance for scalable hydrogen production from water electrolysis. However, the alkaline HER kinetics are impeded by sluggish water dissociation and inefficient proton supply required for its proton-coupled electron transfer process. Herein, we report a facile and effective method to prepare a high-performance alkaline HER catalyst consisting of platinum (Pt) nanoparticles immobilized onto a conductive conjugated coordination polymer (CCP) that is enriched with homogeneous and flexibly regulated single-atom metal sites (15–20 wt%), which can effectively promote water dissociation to ensure efficient proton supply for the active Pt nanoparticles. For a proof-of-concept study, three catalysts consisting of Pt nanoparticles immobilized onto three analogous CCPs with single-atom nickel, copper and cobalt sites were comparatively investigated. The alkaline HER activities of these three catalysts surprisingly follow the same order as the abilities of the single-atom metal sites of CCPs for water dissociation. Our in situ electrochemical impedance spectroscopy, carbon monoxide stripping and kinetic isotope measurements, combined with theoretical studies, unambiguously verify the essential role of the single-atom metal sites of CCP support materials in facilitating alkaline HER kinetics. This strategy opens an alternative avenue for promoting various catalytic reactions that necessitate proton supply from water dissociation.