Investigation of Pristine and (Mo, W)-Doped Cu₁₁V₆O₂₆ for Use as Photoanodes for Solar Water Splitting

Abstract

The development of new and inexpensive semiconductor electrodes that possess suitable bandgap energies and band positions for solar water splitting is of great interest in the field of solar fuel production. In this study, n-type Cu₁₁V₆O₂₆ that has a bandgap energy of 1.9 eV was produced as a pure, high quality photoanode and its properties and stability for photoelectrochemical water splitting were systematically investigated in pH 9.2 and pH 13 solutions. As Cu₁₁V₆O₂₆ photoanodes appeared to suffer from poor charge transport properties, Mo and W-doping into the V site were also examined, which considerably improved the photocurrent generation of Cu₁₁V₆O₂₆. Furthermore, the bandgap energy, band edge positions, flatband potential, photocurrent generation, and photostability of pristine and doped Cu₁₁V₆O₂₆ electrodes are discussed in comparison to elucidate the effect of Mo- and W-doping and to evaluate the promise and limitations of Cu₁₁V₆O₂₆ as a photoanode for use in a water splitting photoelectrochemical cell.