Hollow g‐C₃N₄@Ag₃PO₄ Core–Shell Nanoreactor Loaded with Au Nanoparticles: Boosting Photothermal Catalysis in Confined Space

Abstract Low solar energy utilization efficiency and serious charge recombination remain major challenges for photocatalytic systems. Herein, a hollow core–shell Au/g‐C₃N₄@Ag₃PO₄ photothermal nanoreactor is successfully prepared by a two‐step deposition method. Benefit from efficient spectral utilization and fast charge separation induced by the unique hollow core–shell heterostructure, the H₂ evolution rate of Au/g‐C₃N₄@Ag₃PO₄ is 16.9 times that of the pristine g‐C₃N₄, and the degradation efficiency of tetracycline is increased by 88.1%. The enhanced catalytic performance can be attributed to the ordered charge movement on the hollow core–shell structure and a local high‐temperature environment, which effectively accelerates the carrier separation and chemical reaction kinetics. This work highlights the important role of the space confinement effect in photothermal catalysis and provides a promising strategy for the development of the next generation of highly efficient photothermal catalysts.