The Optimized Catalytic Performance of Single‐Atom Catalysts by Incorporating Atomic Clusters or Nanoparticles: In‐Depth Understanding on Their Synergisms

The performance optimization of single‐atom catalysts (SACs) is important but remains challenging. Taking advantage of accompanying in situ formation of atomic clusters (ACs)/nanoparticles (NPs) during the preparation of SACs can be a promising solution. The coupled ACs/NPs and single atoms (SAs) can be highly efficient in catalyzing various reactions (e.g., oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), CO 2 reduction reaction (CO 2 RR), N 2 oxidation reaction (NOR), etc), showing superior activity, selectivity, and stability. The mechanisms can be mainly categorized as ACs/NPs intensified SAs, SAs intensified ACs/NPs, and reactions proceeding on both ACs/NPs and SAs. The proposed mechanisms may be applicable to rationalize the excellent catalysts consisting of ACs/NPs and SAs. In the end, the existing issues and further development directions are put forward. This review is expected to simultaneously contribute to the development and application of highly efficient SACs and the in‐depth understanding of the single‐atom catalysis (SAC).