A New Synthetic Strategy of Ag‐TiO₂ Nanocomposites Based on Ligand‐to‐Metal Charge Transfer under Visible Light Irradiation: Characterizations and Photocatalytic Activity

Abstract

Ag-TiO 2 nanocomposites are green-synthesized by photodeposition based on ligand-to-metal charge transfer (LMCT) for the first time. Ag þ is photoreduced into Ag nanoparticles under visible light irradiation and precipitated on the surface of TiO 2 (P25) nanoparticles. The physicochemical properties of as-synthesized nanocomposites are characterized by high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet (UV)-visible diffuse reflection spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity of Ag-TiO 2 is evaluated by the photodegradation of methyl orange (MO) under UV light irradiation. 5.0 wt% Ag-P25 nanocomposite exhibited the highest photocatalytic activity, mainly owing to the lowest recombination rate of photogenerated charge carriers. Addition of different scavengers proved that photogenerated electrons and • O À 2 contributed to the photocatalytic decolorization of MO. The as-prepared Ag-P25 nanocomposites had better photocatalytic ability than that of bare P25. Thus, the LMCT-sensitization-induced visible light reduction method is helpful for the green synthesis of photocatalytic nanomaterials and potentially applicable to pollutant remediation.