Competitive photoelectrochemical methanol and water oxidation with hematite electrodes.

Photocatalytic water and methanol oxidation were studied at thin film hematite electrodes synthesized by atomic layer deposition (ALD). Systematic photoelectrochemical characterization along with O2 evolution measurements were carried out in order to better understand the mechanisms of both water and methanol oxidation at hematite electrodes. When both water and methanol are present in the solution, they are oxidized competitively with each other, allowing the detection and assignment of distinct surface states characteristic to each process. The measurement of different surface states for methanol and water oxidation, along with the absence of measurable surface states in an inert acetonitrile electrolyte, clearly shows that the detected surface states are chemically distinct reaction intermediates of water or methanol oxidation.