Morphologically tailored CuO photocathode using aqueous solution technique for enhanced visible light driven water splitting

Abstract

Cupric oxide (CuO) nanostructures are grown on fluorine doped tin oxide (FTO) coated glass substrate using aqueous solution approach. The concentration of precursor's solution has significant impact on morphology of CuO nanostructure. By varying concentration of precursor, the growth of two different morphologies (oriented nanosheets and nanoleaves) is achieved. X-ray diffraction pattern and X-ray photoelectron spectroscopy reveals formation of pure CuO crystalline phase. Mott-Schottky characteristic confirms the p-type semiconducting nature. Ultrathin structures of nanoleaves lead to higher light trapping and light absorption in visible-NIR region. The nanoleaves film has lower bandgap in comparison with nanosheets film. Photoelectrochemical measurements result in 1.5 mA/cm2 photocurrent for nanoleaves electrode and 1.1 mA/cm2 for nanosheets electrode at a potential of 0 V v/s RHE. The photocurrent conversion efficiency is 1.8% and 1.4% in nanoleaves and nanosheets electrodes, respectively. Electrochemical impedance analyses endorse more efficient collection and separation of charge carriers in nanoleaves film. © 2017 Elsevier B.V.