Visible Light Driven Photoanodes for Water Oxidation Based on Novel r-GO/β-Cu₂V₂O₇/TiO₂ Nanorods Composites

This paper describes the preparation and the photoelectrochemical performances of visible light driven photoanodes based on novel r-GO/β-Cu₂V₂O₇/TiO₂ nanorods/composites. β-Cu₂V₂O₇ was deposited on both fluorine doped tin oxide (FTO) and TiO₂ nanorods (NRs)/FTO by a fast and convenient Aerosol Assisted Spray Pyrolysis (AASP) procedure. Ethylenediamine (EN), ammonia and citric acid (CA) were tested as ligands for Cu²⁺ ions in the aerosol precursors solution. The best-performing deposits, in terms of photocurrent density, were obtained when NH₃ was used as ligand. When β-Cu₂V₂O₇ was deposited on the TiO₂ NRs a good improvement in the durability of the photoanode was obtained, compared with pure β-Cu₂V₂O₇ on FTO. A further remarkable improvement in durability and photocurrent density was obtained upon addition, by electrophoretic deposition, of reduced graphene oxide (r-GO) flakes on the β-Cu₂V₂O₇/TiO₂ composite material. The samples were characterized by X-ray Photoelectron Spectroscopy (XPS), Raman, High Resolution Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM), Wide Angle X-ray Diffraction (WAXD) and UV-Vis spectroscopies. The photoelectrochemical (PEC) performances of β-Cu₂V₂O₇ on FTO, β-Cu₂V₂O₇/TiO₂ and r-GO/β-Cu₂V₂O₇/TiO₂ were tested in visible light by linear voltammetry and Electrochemical Impedance Spectroscopy (EIS) measurements.