Single-atom catalysts: In search of the holy grails in catalysis

This perspective assesses the recent progress using single-atom catalysts for five "holy grail" reactions, including partial methane oxidation to methanol, non-oxidative methane conversion, photocatalytic CO2 reduction, photocatalytic water splitting, and nitrogen activation. Using selected case studies, we discuss promising efforts in these domains and at the same time identify the remaining challenges in using SACs for selective and efficient chemical transformations across thermal, electrical, and light-driven catalysis. Looking forward, we highlight the significant potential of SAC research in areas like mechanistic studies, high-throughput screening, and novel catalytic system design.