Review on the Carbon‐Supported Metal Catalysts with Coexistence of Single Atoms and Nanoparticles/Clusters for Electrocatalysis

Abstract Combining homonuclear or heteronuclear nanoparticles and clusters with single‐atom catalysts (i.e., NMP‐SACs) has become a strategy for developing efficient supported metal catalysts. In recent years, NMP‐SACs have garnered increased attention from various fields due to their innovative structures and superior catalytic performance. Compared to conventional single‐atom catalysts, NMP‐SACs achieve enhanced activity and stability through multiple effective mechanisms. For example, they can optimize kinetic processes via synergistic effects, or NMPs can promote charge redistribution at single‐atom (SA) sites. Emerging studies demonstrate that metal‐center electronic configurations in NMP‐SACs can be precisely tailored through metal‐support interactions, enabling optimized adsorption energetics of reactive intermediates. This electronic engineering strategy critically enhances reaction kinetics for fundamental processes, including oxygen evolution (OER), hydrogen evolution reactions (HER), and other electrocatalytic reactions. This review systematically summarizes recent advancements in NMP‐SACs across diverse catalytic scenarios. We first critically assess synthetic strategies and characterization methodologies, followed by a mechanistic analysis of their electrocatalytic performance in representative reactions. The origin of their superior activity is elucidated through electronic structure‐property correlations. Finally, we discuss persistent challenges and propose future research directions for optimizing NMP‐SACs.