Isolating Single and Few Atoms for Enhanced Catalysis

Atomically dispersed metal catalysts have triggered great interest in the field of catalysis owing to their unique features. Isolated single or few metal atoms can be anchored on substrates via chemical bonding or space confinement to maximize atom utilization efficiency. The key challenge lies in precisely regulating the geometric and electronic structure of the active metal centers, thus significantly influencing the catalytic properties. Although several reviews have been published on the preparation, characterization, and application of single‐atom catalysts (SACs), the comprehensive understanding of SACs, dual‐atom catalysts (DACs), and atomic clusters has never been systematically summarized. Here, recent advances in the engineering of local environments of state‐of‐the‐art SACs, DACs, and atomic clusters for enhanced catalytic performance are highlighted. Firstly, various synthesis approaches for SACs, DACs, and atomic clusters are presented. Then, special attention is focused on the elucidation of local environments in terms of electronic state and coordination structure. Furthermore, a comprehensive summary of isolated single and few atoms for the applications of thermocatalysis, electrocatalysis, and photocatalysis is provided. Finally, the potential challenges and future opportunities in this emerging field are presented. This review will pave the way to regulate the microenvironment of the active site for boosting catalytic processes. Atomically dispersed metal catalysts have become an attractive frontier in the field of catalysis. The latest advances in synthesis strategies, local environment regulation, and catalytic applications, covering single‐atom, dual‐atom, and atomic cluster catalysts, are reviewed, while practical solutions to inspire the microenvironment regulation of active sites in the isolated few atom systems are provided.