Enhanced Photoelectrocatalytic Activity of FTO/WO3/BiVO4 Electrode by Modified With Gold Nanoparticles for Water Oxidation Under Visible Light Irradiation

Gold nanoparticles were successfully deposited on FTO/WO3/BiVO4 electrode surface by means of electrolysis of AuCl4 - ions. The composite films were characterized by SEM, XPS and XRD techniques. An increase in photocurrent and a negative shift of onset potential for water oxidation were observed upon modification of the electrode surface with the Au particles. The electrochemical impedance spectroscopy was used to confirm the acceleration of charge transfer process by Au deposition at the electrode surface. The photocurrent action spectrum did not correlate with the plasmonic absorbance of Au nanoparticles at 560 nm, suggesting that the Au nanoparticles increased charge separation without undergoing a plasmon resonance effect under visible light irradiation

Efficient Photocatalytic Activity of Water Oxidation over WO3/BiVO4 Composite under Visible Light Irradiation

A coupled WO3/BiVO4 thin film has been deposited on FTO substrate by a spin coating method from precursor solutions. The composite films were characterized by AFM, SEM, XPS and XRD techniques. The incident photon to current efficiency (IPCE) of BiVO4 electrode was increased by ten times when a WO3 film was layered between the BiVO4 layer and the FTO substrate. The enhanced performance of WO3/BiVO4 composite film electrode is mainly ascribed to the effective electron-hole separations at the semiconductor heterojunction. A schematic mechanism of charge transfer was proposed to explain the photocurrent enhancement for the WO3/BiVO4 electrode surface