Effects of Ag⁰-modification and Fe³⁺-doping on the structural, optical and photocatalytic properties of TiO₂

Abstract

Pure TiO₂, Ag⁰-modified TiO₂, Fe³⁺-doped TiO₂, and Ag⁰-modified/Fe³⁺-doped TiO₂ photocatalysts were synthesized <i>via</i> sol-gel technology. The crystal structure, element composition and surface morphology of the obtained photocatalysts were characterized <i>via</i> XRD, XPS, SEM and TEM, respectively. The results indicate that Ag-TiO₂ samples show higher photocatalytic activity than pure TiO₂. Unexpectedly, the photocatalytic activities of Fe-TiO₂ and 1% Ag/1% Fe-TiO₂ are lower than pure TiO₂. To analyze the main factors affecting photocatalytic performance, the samples were further investigated by PL, DRS and BET. The results prove that the additions of Ag and Fe are advantageous for inhibiting the recombination of photoinduced pairs and improving the utilization of light. Fe-TiO₂ and 1% Ag/1% Fe-TiO₂ exhibit smaller specific surface areas than pure TiO₂, which is the primary reason for their reduced photocatalytic performances.