Platinum‐Nickel Oxide Cluster‐Cluster Heterostructure Enabling Fast Hydrogen Evolution for Anion Exchange Membrane Water Electrolyzers

Abstract Carbon black has been extensively employed as the support for noble metal catalysts for electrocatalysis applications. However, the nearly catalytic inertness and weak interaction with metal species of carbon black are two major obstacles that hinder the further improvement of the catalytic performance. Herein, we report a surface functionalization strategy by decorating transition metal oxide clusters on the commercial carbon black to offer specific catalytic activity and enhanced interaction with metal species. In the case of NiO x cluster‐decorated carbon black, a strongly coupled cluster‐cluster heterostructure consisting of Pt clusters and NiO x clusters (Pt−NiO x /C) is formed and delivers greatly enhanced alkaline hydrogen evolution kinetics. The NiO x clusters can not only accelerate the hydrogen evolution process as the co‐catalyst, but also optimize the adsorption of H intermediates on Pt and stabilize the Pt clusters. Notably, the anion exchange membrane water electrolyzer with Pt−NiO x /C as the cathode catalyst (with a loading of only 50 μ g Pt cm −2 ) delivers the most competitive electrochemical performance reported to date, requiring only 1.90 V to reach a current density of 2 A cm −2 . The results demonstrate the significance of surface functionalization of carbonaceous supports toward the development of advanced electrocatalysts.