Preparation and photocatalytic activity of Ag-modified GO-TiO2 mesocrystals under visible light irradiation

Nanosized metallic Ag particles modified graphene oxide-TiO2 mesocrystals (Ag/GO-TMCs) were successfully synthesized by photoreduction deposition method. The morphology, crystallization, structural features and chemical compositions of the as-prepared Ag/GO-TMCs catalysts were investigated using HRTEM, XRD, Raman spectra, XPS, UV–vis DRS, PLS, and N2 adsorption-desorption measurements. Ag nanoparticles were found to be evenly distributed on the surface of TiO2 mesocrystals (TMCs) and graphene oxide (GO). The Ag/GO-TMCs catalysts featured high crystallinity, abundant mesoporous structure, large surface area, and improved visible-light response. Photocatalytic applications of the catalysts for degradation of Rhodamine B (RhB) and dinitro butyl phenol (DNBP) under visible light irradiation were investigated. The results showed that the highly enhanced photocatalytic activity was obtained with Ag/GO-TMCs catalysts. The Ag/GO-TMCs photocatalyst with AgNO3/GO-TMCs mass ratio of 0.075:1 exhibited the highest photocatalytic degradation of RhB and DNBP under 3 h of visible light irradiation. The superior photocatalytic activity of Ag/GO-TMCs may be attributed to the higher visible-light absorbance ability and surface plasmon resonance (SPR) effect of Ag nanoparticles and GO. The Ag-GO/TMCs materials could be deemed as promising photocatalysts for organic contaminants removal under visible light irradiation, in assessing their high photocatalytic efficiency and good repeatability.