Single-atom catalysts: From atomic-level engineering to application

Single-atom catalysts (SACs), featuring atomically dispersed metal active sites, have recently emerged as a new frontier in catalysis science. By maximizing atom-utilization efficiency and enabling precise modulation of active-site structures, SACs demonstrate broad application potential across diverse important fields including catalysis, energy storage, and biomedicine. Beginning by tracing the evolutionary trajectory of single-atom catalysis, this review expands its discussion to encompass strategies for modulating single-atom active sites, techniques for synthesizing atomically dispersed metals, and advanced characterization methods for atomic-level analysis. Furthermore, this paper systematically reviews recent advances in SACs for energy, environmental, and biological applications, covering cutting-edge processes such as water electrolysis, advanced battery, pollutant degradation and biosensing. A central focus on correlating active-site structures with catalytic mechanisms and performance provides this review with a distinctive perspective. In light of the ongoing challenges associated with the transition from laboratory-scale research to device integration, this article proposes potential solutions and future research directions, offering a theoretical foundation and technical pathway for the rational design of high-performance single-atom catalytic systems.