Controlled synthesis of thorny anatase TiO2 tubes for construction of Ag-AgBr/TiO2 composites as highly efficient simulated solar-light photocatalyst

This work reports on a two-stage strategy towards the controlled Ag-AgBr deposition onto thorny anatase TiO2 tubes for excellent simulated solar-light photocatalytic activities. First, anatase TiO2 tubes with a thorny porous external surface were prepared using rod-like TiOSO4 center dot 2H(2)O as sacrificial template and a Ti source via a solvothermal process followed by annealing. The formation mechanism of the anatase TiO2 tubular precursor was investigated in detail. Then, the prepared anatase TiO2 tubes were used as a support for loading AgBr nanoparticles using the deposition-precipitation method, and the deposited AgBr was partially reduced to Ag via the calcination process to fabricate the Ag-AgBr/TiO2 tubular composites. X-Ray absorption near edge spectra (XANES), extend X-ray absorption fine structure (EXAFS) spectra and X-ray photoelectron spectroscopy (XPS) analyses indicated that both AgBr and Ag-0 components coexist in the systems. Compared with conventional nanoparticles and nanotubes, there exist abundant microcavities in the roughly parallel nanothorns of the tubes, which can contribute to the stable deposition of the Ag-AgBr nanoparticles and the formation of effective nanojunctions. These composites exhibited superior photocatalytic activity in the degradation of phenol under simulated solar-light irradiation.