Plasmonic resonance nature of Ag-Cu/TiO 2 photocatalyst under solar and artificial light: Synthesis, characterization and evaluation of H 2 O splitting activity

A reaction mechanism has been elucidated on Ag and/or Cu supported on mixed phase (anatase/rutile) of TiO2 and the H2 evolution rates are rationalized by physicochemical characteristics of the fresh and used catalysts by XRD, XPS, TEM and ESR analyses. In situ reduction of Ag-Cu/TiO2 catalyst is monitored by UV-DR spectral studies under natural and artificial light during H2O splitting. The H2-TPR analysis emphasized an interaction between reducible mixed oxides of Ag-Cu particles. Addition of Ag dramatically decreased the band gap of Cu/TiO2 and increased the absorption in the visible light region. The synergism between Ag and Cu nanoparticles generated additional active sites for enhanced H2 yields. A strong interaction between Ag and Cu leads to metal sites (Ag, Cu and/or Ag-Cu) act as electron traps and facilitated electron-hole separation consequently the Ag-Cu/TiO2 sustained longer time.