Photoelectrochemical (PEC) water splitting is an attractive and sustainable energy conversion method. In this work, cobalt phosphide (CoP) is photoelectrochemically deposited on a p-type cuprous oxide (pCu(2)O) photocathode for solar hydrogen production. Under visible light irradiation, the PEC assembly is active for hydrogen evolution, generating a current density of up to -5.3 mA cm(-2) and -4.2 mA cm(-2) in acidic and basic conditions at 0 V vs. the reversible hydrogen electrode (RHE). (C) 2017 Elsevier Ltd. All rights reserved.