In this paper, Ag/TiO 2 composites with different Ag doping ratios (0.5%, 1%, 2% and 3%) were prepared by a one-pot solvothermal method without post calcination. Glycine promoted the formation of rod-like TiO 2 growing along the (101) plane and introduced Ag nanoparticles (NPS) onto the surface of TiO 2 . A series of characterization tests, including x-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), x-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, nitrogen adsorption and desorption measurement, and electrochemical measurements were employed. The measurements confirmed that the formed Ag/TiO 2 nanorod composite with 1% Ag loading ratio (Ag/TiO 2 -1), consisting of length up to 22 nm and Ag nanoparticles (NPS) with a diameter of about 5.5 nm, had an appropriate energy band gap of 2.95 eV and a large specific surface area of 158.3 m 2 /g, which shows that the Ag/TiO 2 -1 has abundant photocatalytic active sites to increase its visible-light absorption ability. The Ag/TiO 2 -1 sample has the highest photocatalytic efficiency, with up to 95% and 98% degradation for tetracycline (TC) and Rhodamine B (RhB), respectively, in 25 min under simulated solar light. After the sixth cycle experiment, Ag/TiO 2 -1 still maintained 94% and 95% degradation of TC and RhB, respectively. The trapping active species experiment confirmed that the hole (h + ) and superoxide radical \(\left( { \cdot {\text{O}}_{2}^{ - } } \right)\) are the main active species. This work has practical significance for the simultaneous study of the photocatalysis of Ag/TiO 2 composites for dyes (RhB) and antibiotics (TC).
Hongfei Dou,Jie Wang,Yan Zhao,Junjie Liu,Yannan Li
Aiming at the insufficient broad-spectrum absorption and high carrier complexation rate in the photocatalytic antimicrobial application of TiO2, Ag/TiO2composite materials were prepared by co-precipitation method in this study. The material characterization showed that Ag was uniformly dispersed on the TiO2surface in the form of nanoparticles, and the specific surface area of Ag/TiO2composite 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/TiO2composite 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.
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