title: Highly active oxide photocathode for photoelectrochemical water reduction.
abstract: A clean and efficient way to overcome the limited supply of fossil fuels and the greenhouse effect is the production of hydrogen fuel from sunlight and water through the semiconductor/water junction of a photoelectrochemical cell, where energy collection and water electrolysis are combined into a single semiconductor electrode. We present a highly active photocathode for solar H(2) production, consisting of electrodeposited cuprous oxide, which was protected against photocathodic decomposition in water by nanolayers of Al-doped zinc oxide and titanium oxide and activated for hydrogen evolution with electrodeposited Pt nanoparticles. The roles of the different surface protection components were investigated, and in the best case electrodes showed photocurrents of up to -7.6 mA cm(-2) at a potential of 0 V versus the reversible hydrogen electrode at mild pH. The electrodes remained active after 1 h of testing, cuprous oxide was found to be stable during the water reduction reaction and the Faradaic efficiency was estimated to be close to 100%.
authors.affiliation: Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Laboratory of Photonics and Interfaces, Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: Adriana
authors.initials: A
authors.lastname: Paracchino
authors.forename: Vincent
authors.initials: V
authors.lastname: Laporte
authors.forename: Kevin
authors.initials: K
authors.lastname: Sivula
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: Elijah
authors.initials: E
authors.lastname: Thimsen