Photocatalytic deposition of Ag nanoparticles on TiO2: Metal precursor effect on the structural and photoactivity properties

Abstract A series of 1 wt.% Ag–TiO 2 photocatalysts were obtained by photodeposition using different organic (acetylacetonate, Ag-A) and inorganic (nitrate, Ag-N, and perchlorate, Ag-C) silver precursors in order to determinate the influence of the silver precursor on final properties of the photocatalysts. The resulting photocatalytic materials were characterized by different techniques (UV–Vis DRS, TEM/HRTEM and XPS) and their photocatalytic activity was evaluated in the degradation of rhodamine B (used as model pollutant) in aqueous solution under simulated solar light. The photocatalytic reduction of Ag species to Ag 0 on TiO 2 was higher with silver nitrate as precursor compared to acetylacetonate or perchlorate. All the Ag-modified TiO 2 photocatalysts exhibited a surface plasmon resonance effect in the visible region (400–530 nm) indicating different metal particle sizes depending on the Ag precursor used in their synthesis. A higher photocatalytic activity was obtained with all the Ag/TiO 2 samples compared with non-modified TiO 2 . The descending order of photocatalytic activity was as follows: Ag-A/TiO 2  ≈ Ag-N/TiO 2  > Ag-C/TiO 2  > TiO 2 -P25. The enhanced photoactivity was attributed to the presence of different amounts Ag 0 nanoparticles homogeneously distributed on Ag 2 O and TiO 2 , trapping the photogenerated electrons and avoiding charge recombination.