Dataset of "CuBi2O4 Electrodes for Solar-Driven Photoelectrochemical Reduction Reactions"

Properties of thin films of p-CuBi2O4 synthesized by spin coating were investigated physically and photo(electro)chemically. The chemical stability was evaluated. In 1 M H2SO4 complete dissolution within 10 seconds occurred, whereas, in contrast, the electrodes remained stable after immersion in 1 M NaOH for 24 hours. Photoelectrochemical measurements were conducted in aqueous electrolytes saturated with O2, air or N2 and in the presence of H2O2 or methylviologen (MV2+). Incident photon to current efficiencies (IPCE) indicated a bandgap of 1.8 eV. The position of the valence band was estimated from the open circuit potential under illumination to lie at 0.515 V vs. Ag/AgCl at pH 6 (1.08 V vs. RHE), which could be considered close to the flat band potential (EFB). Photocurrents under nitrogen bubbling rapidly decreased and the exposed area changed its colour from brown to black, indicating destruction of the electrode. When oxygen saturated solutions ([O2] = 1.23 mM) were used, the photocurrents and the electrodes were found stable (tested for a duration of up to 24 h (57 C/cm2) and some H2O2 was detected as a product of oxygen reduction. As H2O2 is an electron scavenger itself, most of it was reduced to H2O. H2O2 (10 mM) stabilized the photocurrents as well, whereas methylviologen (MV2+) led to much lower photocurrents and the electrodes could not be stabilized.