Explosive advances of metal-organic frameworks-derived single atom catalysts modified by metal species in diverse sizes for electrocatalysis: Synthesis, collaboration, and mechanism

Metal-organic frameworks derived single atom catalysts (MOF-derived SACs) have attracted widespread attention in the electrocatalysis field due to the maximum atomic economy and exceptional reactivity toward catalysis. However, one pivotal obstacle to the catalytic performance is the complex multiple electron reactions, which still encounter challenges by solely relying on the single active sites. Fortunately, the introduction of metal species of diverse sizes into SACs (DSM-SACs) is expected to integrate their respective advantages and significantly enhance the activity and selectivity of catalysts. A comprehensive review is urgently needed to offer a concise overview of the recent progress in DSM-SACs. Herein, this review initially systematically examined the synthesis strategies for MOF-derived DSM-SACs, focusing on the discrepancy of metal sources provided by MOFs. Subsequently, the distinctive cross-size multiple synergistic mechanisms of MOF-derived DSM-SACs were thoroughly elucidated. Furthermore, in conjunction with the mechanisms underlying various electrocatalytic reactions, the significant breakthroughs across different electrocatalytic processes were delineated. Finally, the research challenges and the future development directions of synergistic structures were discussed. This review will facilities the fundamental understanding of molecular mechanisms and provided efficient principles aimed at improving electrocatalytic performance for MOF-derived SACs and beyond.