Conjugated coordination polymer enables efficient proton supply on platinum surface for alkaline hydrogen evolution electrocatalysis

Abstract

Developing high-performance alkaline hydrogen evolution reaction (HER) is of great significance for scalable hydrogen production from water electrolysis. However, the alkaline HER kinetics are impeded by the sluggish water dissociation and inefficient proton supply necessitated in its proton-coupled electron transfer process. Herein, we report a facile and effective method to prepare high-performance alkaline HER catalyst 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 the proof-of-concept study, three catalysts of Pt nanoparticles immobilized onto three analogous CCP 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 CCP 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 towards facilitating alkaline HER kinetics. This strategy opens an alternative avenue for promoting various catalytic reactions that necessitate proton supply from water dissociation.