Activation Energies for the Rate-Limiting Step in Water Photooxidation by Nanostructured alpha-Fe(2)O(3) and TiO(2) - Cowan, AJ; Barnett, CJ; Pendlebury, SR; Barroso, M; Sivula, K; Graetzel, M; Durrant, JR; Klug, DR (2011)