Confeito-like Au/TiO2 nanocomposite: synthesis and plasmon-induced photocatalysis

Nanocomposites of confeito-like Au nanoparticles (CAuNPs) and TiO 2 were synthesized under different irradiation conditions (darkness, UV light, and visible light) and time spans by the reaction of a Ti-citrate-peroxo complex with CAuNPs. The TiO 2 synthesized under irradiation formed mesoporous films with embedded CAuNPs. The photocatalytic activity of the CAuNP/TiO 2 nanocomposites was measured by the degradation of methylene blue (MB) under different irradiation conditions (darkness, UV light, and visible light). The results demonstrated that the bare CAuNPs decomposed MB under visible light and that this activity was enhanced by hybridization with TiO 2 . The activity of the CAuNPs was associated with the plasmon-induced effect, which the TiO 2 enhanced by suppressing electron-hole recombination via acceptance of the hot electrons from the CAuNPs. This synergistic effect of the CAuNP/TiO 2 nanocomposite varied with the amount of TiO 2 , and a thick layer of TiO 2 decreased the activity as the surface of the CAuNPs was covered by TiO 2 . This behavior indicates that to design effective plasmonic devices and catalysts, an optimum balance between the amounts of CAuNPs and TiO 2 must be achieved.