Electrodeposited p-type Cu2O for H2 evolution from photoelectrolysis of water under visible light illumination

Electrochemical deposition of p-type Cu2O films on transparent conducting glass from a Cu2SO4 solution was conducted at different temperatures. The films were examined for H-2 evolution from photoelectrolysis of water under visible light illumination. Using Pt as the counter electrode, photocurrents with corresponding H-2 evolution could be observed for the deposited Cu2O films in a Na2SO4 solution under a cathodic bias. The Cu2O films obtained at different deposition temperatures were in the cubic phase, but showed different out-of-plane crystalline orientations. An incident monochromatic photon-to-current conversion efficiency of 26% at 400nm was achieved for a Cu2O film with a [111] out-of-plane orientation, while an efficiency of only 17% was obtained for a film with a [110] orientation. The [111]-oriented film exhibited a higher electronic conductivity, which might have led to a higher charge delocalization rate. By coupling with an n-type WO3 film to promote charge transport, the photocurrent for the Cu2O films was significantly improved. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.