Effects of Ag modified TiO2 on local structure investigated by XAFS and photocatalytic activity under visible light

Abstract

Silver modified titanium dioxide (Ag-TiO2) nanoparticles at different loading (3–10 mol%) were synthesized via dry and wet ball milling sol-gel method. Effects of doped Ag on local TiO2 structure were investigated. The presence of Ag+-ion in TiO2 structure was confirmed by XANES and EXAFS findings, resulting in Ag substitution and oxygen vacancy in TiO2. The phase transformation and modification of lattice parameters of anatase and rutile phases in the TiO2 structure following Ag doping were revealed by XRD and XANES and confirmed that Ag was successfully introduced into the TiO2 structure. When Ag doping content was increased from 3% to 10%, the number of Ag nanoparticles deposited on the TiO2 surface increased. The low Ag doping contents (3% and 5% Ag-TiO2) displayed better photocatalytic activity of 3.5 mg/L MB degradation under visible light than the high Ag doping contents (6% and 10% Ag-TiO2).