Photoelectrochemistry of Porous p-Cu[sub 2]O Films

Porous p-Cu 2 O films were prepared on transparent conductive glass from a dispersion of Cu 2 O powder in ethanol.Upon illumination with a 100 W tungsten lamp, the photocurrent of the porous Cu 2 O film was appreciably greater when compared to electrodeposited Cu 2 O films.The enhancement is attributed to the increased interfacial area between the film and the solution due to the three-dimensional nature of the Cu 2 O film.No chemical change was detected by visual examination and X-ray diffraction of the porous Cu 2 O film after illumination for 2 h in the aqueous solution at -0.4 V vs saturated calomel electrode.The reported stability of electrodeposited Cu 2 O films is attributed to the effect of Cu + -terminated ͑111͒ surface, where the H + -assisted photoreduction of Cu 2 O is less likely to occur.The well-known instability of single-crystal Cu 2 O is hypothesized to be due to the predominating ͑211͒ and ͑311͒ surfaces, where the photodecomposition to Cu is inevitable at the exposed O 2-sites.