Recent advances in synergetic catalysis of single atom catalysts in biomass conversion, CO₂ reduction, and cascade reaction

Single-atom catalysts (SACs) have demonstrated immense potential in the fields of energy and biochemical conversions. Their unique properties make them particularly afford higher efficiency and selectivity. Characterized by their unique isolated state on supports, SACs often showcase poor synergy in the multiple molecule conversion because of the infrequent communications with others. Recently, some interesting synergetic processes of SACs in some special reactions have been found, however, to our best knowledge, the synergetic catalytic effect of SACs has not been systematically summarized. This article comprehensively overviews the basic concepts, mainstream synthetic methods, and modification strategies of SACs and emphasizes the synergetic catalysis effect in biomass conversion, CO₂ reduction, and cascade reaction by itself or other media. To maximize the advantage of SACs, various synthetic methods for SACs, including impregnation, co-impregnation, co-precipitation, atomic layer deposition, electrochemical methods, photochemical methods, pyrolysis synthesis, spray pyrolysis method, ball-milling and chemical vapor deposition method are discussed. This review provides a comprehensive discussion concerning the dynamic interplay between precisely engineered atomic architectures and their synergistic functionalities in modulating catalytic efficacy, with focused exploration of activity enhancement strategies and operational stability optimization. Distinctively, it pioneers the establishment of comprehensive theoretical frameworks that unify SAC-driven synergistic catalytic mechanisms across three critical domains: biomass valorization, electrochemical CO₂ conversion, and multi-step cascade processes. Through systematic synthesis of cutting-edge developments in coordination microenvironment modulation, inter-site electronic communication, and fundamental mechanistic studies, this work affords some interesting insight into rational design of synergistic SAC systems, thereby addressing current challenges in translating atomic-scale precision to heterogeneous catalytic performance.