Highly orientated one-dimensional Cu2O/TiO2 heterostructure thin film for photoelectrochemical photoanode and photocatalytic degradation applications

Abstract

A highly orientated one-dimensional TiO2 nanorod (NR) and TiO2 NR coupled with Cu2O growth on a fluorine doped tin oxide (FTO) substrate were fabricated by the hydrothermal method. A p-n Cu2O/TiO2 heterostructure photoanode was applied for photoelectrochemical water splitting and photocatalytic organic dye degradation application. The purpose of using Cu2O is to extend the visible light absorption capacity and improve the charge transport and charge carrier lifetime of the TiO2 based photoanode. The materials were characterized by various methods. Scanning electron microscopy image revealed that the Cu2O/TiO2 was well aligned perpendicular to the FTO substrate. Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed that Cu2O was coated on the TiO2 surface. The absorption spectra showed the energy bandgap of pristine TiO2 decreased after the Cu2O enhancement. Electrochemical impedance spectroscopy revealed that the charge carrier and charge transport of the Cu2O/TiO2 material were improved. Overall photocurrent density generated by the Cu2O/TiO2 photoanodes were higher than the pristine TiO2 photoanode when they were applied as the photoanode in the photoelectrochemical cell. For the thin film Rhodamine B degradation, the Cu2O/TiO2 photocatalyst showed a better performance than the pure TiO2 NR thin film by ∼60%.