Complex Oxides Based on Silver, Bismuth and Tungsten: Syntheses, Characterization and Photoelectrochemical Behavior

Silver-containing complex oxides present interesting light absorption and electronic properties pointing to their applicability for solar fuel generation and environmental remediation. In this vein, the syntheses, characterization, and photoelectrochemical properties of the Aurivillius oxide, AgBiW₂O₈, and a triphasic material, AgBiW₂O₈/Bi₂WO₆/Ag, are described herein. From UV–vis diffuse reflectance analysis, both oxides’ nanoparticles exhibited intense absorption at wavelengths <455 nm, with an additional band centered at ∼500 nm for the triphasic material, attributed to surface plasmon resonance of the metallic Ag phase. The triphasic material was further characterized by a variety of structural and spectroscopic probes, indicating a defect-rich crystalline structure. Voltammetric measurements were performed in the dark and under simulated solar irradiation with polarization at potentials more negative than the rest potential. Thin film electrodes of both materials showed p-type semiconductor behavior, with enhanced cathodic photocurrent in the presence of electron acceptors in aqueous media