Synergistic effect of Ag@AgX (X = Cl, Br, I)-TiO2 nanosheets composite catalysts for enhanced visible-light photocatalytic degradation of Rhodamine B

A series of photocatalysts, including Ag@AgX-TiO2 and composite AgX-TiO2 materials (AgI/AgCl-TiO2 and Ag@AgI/AgCl-TiO2), were successfully synthesized in this work. These materials were systematically characterized using multiple spectroscopic techniques. Their photocatalytic performance was evaluated through the degradation of Rhodamine B (RhB), which demonstrated that all as-prepared catalysts exhibited significantly enhanced activity under visible light compared to pure TiO2 nanosheets. This work systematically compares the contributions of localized surface plasmon resonance (LSPR) from Ag nanoparticles with both the individual and synergistic effects of various AgX heterojunctions in photocatalysis. The enhancement in photocatalytic performance is attributed to strong visible-light absorption by the catalyst, combined with efficient electron-hole separation enabled by the cooperative action of Ag LSPR and AgX heterojunctions. In addition, the photo-corrosion of AgX is effectively suppressed by the presence of Ag, leading to improved catalyst stability. This work leverages a combination of experimental characterization and density functional theory (DFT) calculations to unravel the intrinsic charge transfer pathway and underlying reaction mechanism.