The Role of Cobalt Phosphate in Enhancing the Photocatalytic Activity of alpha-Fe2O3 toward Water Oxidation

Transient absorption spectroscopy was used to probe the dynamics of photogenerated charge carriers in alpha-Fe2O3/CoOx nanocomposite photoelectrodes for water splitting. The addition of cobalt-based electrocatalysts was observed to increase the lifetime of photogenerated holes in the photoelectrode by more than 3 orders of magnitude without the application of electrical bias. We therefore propose that the enhanced photoelectrochemical activity of the composite electrode for water photooxidation results, at least in part, from reduced recombination losses because of the formation of a Schottky-type heterojunction.