Synergistic effect of interfacial lattice Ag+ and Ag0 clusters in enhancing the photocatalytic performance of TiO2

Abstract

An interfacial lattice Ag⁺ doped on TiO₂ (Ag⁺/TiO₂) was prepared by eluting Ag⁰ clusters from a hydrothermally prepared Ag⁰/Ag⁺/TiO₂ composite. An Ag⁺/TiO₂@Ag⁰ composite photocatalyst was subsequently obtained via a secondary Ag⁰ clusters loading process to the Ag⁺/TiO₂. The photocatalytic activity of Ag⁺/TiO₂@Ag⁰ was greatly improved compared to Ag⁰/Ag⁺/TiO₂ and Ag⁺/TiO₂. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) testing verified that Ag⁺ ions occur as an interfacial lattice Ag⁺ species in the composites. The enhancement effect of the interfacial lattice Ag⁺ species is exhibited by the newly-formed Ag⁺/TiO₂@Ag⁰ as the interfacial lattice Ag⁺ is fully exposed but not overlapped with the re-loaded Ag⁰ clusters. The interfacial lattice Ag⁺ ions and Ag⁰ clusters are both responsible for the photocatalytic performance improvement of the catalyst, in either the photocatalytic degradation of methyl orange or photocurrent measurement.