Abstract
We study hematite (alpha-Fe2O3) photoelectrodes for water splitting by examining the fate of photogenerated holes. Using H2O2 as an efficient hole scavenger, we collect all holes that arrive at the electrode/electrolyte interface. This provides the ability to distinguish between and quantify bulk and surface recombination processes involved in the photoelectrochemical oxidation of water. Below 1.0 V-RHE, electrolyte oxidation kinetics limits the performance but above 1.2 V-RHE bulk recombination becomes the limiting factor.