Single-atom sites combined with metal nano-aggregates for efficient electrocatalysis

Abstract

Owing to their respective characteristics, single-atom catalysts (SACs), metal nanoparticle catalysts, and metal nanocluster catalysts exhibit excellent performance in various electrocatalytic reactions. Notably, the composite catalysts containing both metal single-atom (M₁) sites and metal nano-aggregates (MNAs, including nanoparticles and nanoclusters) are expected to integrate the advantages of each for efficient electrocatalysis, which are drawing increasing attention. In this review, we aim to provide a comprehensive overview showing the structure advantages and recent progress of single-atom catalysts containing metal nano-aggregates (MNA–SACs). Specifically, we first retrospectively look at the debates over determining the actual active sites in MNA–SACs, and summarize the structure characteristics and synthetic methods of MNA–SACs. Importantly, the key synergistic effects of the M₁ sites and MNAs in MNA–SACs are thoroughly discussed. Furthermore, the recent progress and representative breakthroughs of advanced MNA–SACs in various electrocatalytic reactions are outlined. Finally, the challenges and prospects for development in MNA–SACs are highlighted. This article aims to present a comprehensive overview of MNA–SACs, expecting to further inspire the development of MNA–SACs and provide new ideas for the rational design of efficient electrocatalysts.