Preparation of Ag-Decorated TiO₂ Composite Materials and Study on Photocatalytic Performance

Aiming at the insufficient broad-spectrum absorption and high carrier complexation rate in the photocatalytic antimicrobial application of TiO₂, Ag/TiO₂ composite materials were prepared by co-precipitation method in this study. The material characterization showed that Ag was uniformly dispersed on the TiO₂ surface in the form of nanoparticles, and the specific surface area of Ag/TiO₂ composite materials was enhanced by 59.6% compared with that of pure TiO₂, and the mesoporous structure was significantly optimized. Visible photocatalytic tests showed that the degradation rate of Ag/TiO₂ composite materials for Rh B and M O was more than two times higher than that of pure TiO₂. Under dark conditions, the material showed a minimum inhibitory concentration (MIC) of 62.5 μg/mL against Escherichia coli and Staphylococcus aureus, with an antimicrobial rate of 99.8% for 8 h, confirming its non-light-dependent antimicrobial activity. Mechanistic studies revealed that photogenerated electrons were efficiently captured by Ag nanoparticles, which inhibited e-h⁺ complexation; meanwhile, the photothermal effect (ΔT > 15 °C) promoted the sustained release of Ag⁺, which realized the triple synergistic antimicrobial activity by disrupting the bacterial membrane and interfering with metabolism. This study provides a new strategy for the development of efficient solar-powered water treatment materials.