Enhanced visible-light activities for PEC water reduction of CuO nanoplates by coupling with anatase TiO2 and mechanism

CuO nanoplates were prepared by a feasible hydrothermal method, and then utilized as photocathodes for photoelectrochemical (PEC) water reduction in a neutral medium under visible-light irradiation. It is clearly demonstrated that the visible-light activities of the resulting nanoplates for PEC water reduction could be greatly improved after coupling with a proper amount of nanocrystalline anatase TiO2. This is attributed to the enhanced charge separation in the fabricated TiO2/CuO nanoplate composites mainly based on the atmosphere-controlled steady-state surface photovoltage spectra. Moreover, it is suggested that the enhanced charge separation resulted from the transfer of visible-light-excited high-energy electrons from CuO to TiO2 as confirmed from the single-wavelength PEC behavior. (C) 2015 Elsevier B.V. All rights reserved.