Deposition of quantum-sized Ag on TiO2 through adsorbed-layer nanoreactor synthesis and its performance for photodegrading phenol in seawater under visible-light irradiation

Abstract

Commercial TiO2 photocatalyst P25 was first used as a support to prepare Ag-deposited catalysts by adsorbed-layer nanoreactor synthesis (ANS). Characterizations were performed by UV–vis diffuse reflectance spectroscopy, TEM, XRD, XPS, PL spectroscopy, and photo-electrochemical analysis. Results showed that Ag nanoparticles with size of less than 10 nm distributed very homogeneously on the TiO2 surface. The adsorption layer on the TiO2 surface acting as a nanoreactor led to tight interaction between quantum-size Ag particles and the TiO2 surface, thereby introducing staggered heterojunction structures into the catalysts. The heterojunction between quantum-sized Ag particles (less than 10 nm) and TiO2 led to the surface plasmon resonance effect and strong visible-light response of catalysts. Ag deposition further caused distortions in TiO2 crystal lattices. Both the heterojunction and TiO2 lattice distortions enhanced the separation efficiency of charge carriers, which improved the photocatalytic activity for phenol in seawater under visible-light irradiation. The catalyst exhibited high stability and reusability after six cycles because of its morphological stability.