Adjusting the local coordination microenvironment of single atoms to optimize catalytic efficiency in renewable...

Single-atom catalysis (SACs) has attracted considerable attention because of its distinctive structural characteristics and strong potential for catalytic innovation. The performance of atomically dispersed catalysts depends on the local microenvironment surrounding the single atoms and neighboring active species. Moreover, the local microenvironment constrains the electronic structure and geometry of the catalyst, thereby determining the efficiency of the energy-conversion devices. However, significant challenges persist in accurately designing the electronic coordination environments and geometric configurations of catalysts at the sub-nanometer scale, which limits effective regulation of the catalytic microenvironment and improvement of catalytic activity. This review provides a comprehensive overview of the cutting-edge progress in enhancing energy conversion efficiency via micro-environmental regulation of single-atom catalysts. Typical techniques for regulating local coordination microenvironments are discussed, including heterogeneous atom anchoring, atomic molecular bridging, defect engineering, spatial confinement, and construction of local microinterfaces. Characterization techniques for probing microenvironments, such as X-ray absorption fine structure spectroscopy, are also summarized. The optimization of single-atom efficiency via local microenvironment regulation has been demonstrated for the HER, OER, ORR, CO₂RR, and NRR. The discussion concludes with an assessment of application prospects and remaining challenges associated with engineering-based microenvironment control, aiming to guide future developments in single-atom precision catalysis and energy conversion devices.