Ligand engineering of Au nanoclusters with multifunctional metalloporphyrins for photocatalytic H2O2 production

Abstract

Ultrasmall metal nanoclusters (NCs) are promising in various photocatalytic applications, but usually suffer from fast recombination of charge carriers, insufficient active sites, and difficult diffusion of substrates onto active sites. Herein, we report the design of a Au NC-based photocatalyst for photocatalytic hydrogen peroxide (H₂O₂) production based on the ligand engineering of Au NCs with porphyrin cobalt (Co-TCPP). Besides enhancing the visible light absorption of Au NCs, the grafted Co-TCPP molecules on the Au NC surface could serve as electron acceptors, which not only efficiently promote charge carrier separation of Au NCs, but also provide abundant active sites for photocatalysis. On this basis, the as-designed Au NC-based photocatalyst showed excellent photocatalytic performance in H₂O₂ production (up to 235.93 μM), outperforming most previously reported semiconductor photocatalysts. In addition, the mechanistic study revealed that the photocatalytic H₂O₂ production over the Au NC-based photocatalyst mainly follows a two-electron O₂ reduction pathway. This study is attractive as it demonstrated the design of the high-performance Au NC-based photocatalyst via ligand engineering, increasing the acceptance of metal NCs for photocatalytic applications.