An ultrathin cobalt-iron oxide catalyst for water oxidation on nanostructured hematite photoanodes

The harvesting of sunlight by a photoelectrochemical (PEC) cell to split water into hydrogen and oxygen is an attractive strategy to store solar energy in the form of chemical bonds. The oxygen evolution reaction (OER) remains a bottleneck for the development of efficient PEC devices. Here we report a photoelectrochemical method to homogeneously deposit a cobalt-iron oxide (CoFeOx) catalyst on a nanostructured hematite photoanode. An ultrathin catalyst layer (