Atomic engineering of copper sites for efficient photocatalysis

The development of high-performance photocatalytic materials is urgently needed to overcome the efficiency limitations of conventional photocatalysis. Copper-based single-atom catalysts (Cu SACs) have emerged as a promising class of materials due to their unique electronic structures, maximized atomic utilization, and highly exposed active sites. This review comprehensively summarizes recent advances in the design, synthesis, and application of Cu SACs in photocatalysis. Key aspects include innovative synthesis strategies for precise atomic dispersion, performance enhancement through coordination modulation, defect engineering, and multi-site synergy, as well as their applications in photocatalytic hydrogen evolution, CO₂ reduction, ammonia synthesis, H₂O₂ production, and pollutant degradation. This review places special emphasis on elucidating the structure-activity relationships and underlying mechanisms governing charge dynamics and surface reactions. Finally, future perspectives on operando characterization and computational-guided design for next-generation SACs are discussed.