Fabrication of CuBi2O4 photocathode through novel anodic electrodeposition for solar hydrogen production

Copper bismuth oxide (CuBi(2)0(4)) film electrodes were fabricated by anodic co-electrodeposition of Bi2O3 and CuO, followed by heat treatment in air at 500 degrees C. The compositions of the electrolyte solution, such as concentrations of Cu2+, Bi3+, and tartaric acid, alkaline strength, and temperature, were optimized to fabricate pure CuBi204 films on FTO substrates. XRD and optical absorption were employed to confirm the formation of CuBi204, and SEM observation showed the fabrication of a closed packed film with good contact to the FTO substrate. Mott-Schottky plots based on Nyquist plots at various potentials gave the flat band potential of 0.62V (vs. Ag/AgCl) at pH 6.0. Since the band gap energy measured was 1.80 eV, the conduction band bottom locates at -0.98 V (vs. NHE). At the potential more negative than 0 V (vs. Ag/AgC1), the photo cathodic current for hydrogen production was observed under visible light irradiation in a deoxygenated 0.1 M Na2SO4 solution. The film electrode sustained the photo electrochemical activity in the electrolyte solution at -0.3 V (vs. Ag/AgCI), at least, for 100 min. (C) 2014 Elsevier Ltd. All rights reserved.