Single-Source Deposition of Mixed-Metal Oxide Films Containing Zirconium and 3d Transition Metals for (Photo)electrocatalytic Water Oxidation

The fabrication of mixed-metal oxide films holds promise for thedevelopment of practical photoelectrochemical catalyst coatings but currentlypresents challenges in terms of homogeneity, cost, and scalability. We report astraightforward and versatile approach to produce catalytically active zirconium-basedfilms for electrochemical and photoelectrochemical water oxidation. Themixed-metal oxide catalystfilms are derived from novel single-source precursoroxide cage compounds containing Zr withfirst-row transition metals such as Co,Fe, and Cu. The Zr-basedfilm doped with Co onfluorine-doped tin oxide (FTO)-coated glass exhibits the highest electrocatalytic O2evolution performance in analkaline medium and an operational stability above 18 h. The deposition of thisfilm onto a BiVO4photoanode significantly enhancesits photoelectrochemical activity toward solar water oxidation, lowering the onset potential by 0.12-0.21 V vs reversible hydrogenelectrode (RHE) and improving the maximum photocurrent density by similar to 50% to 2.41 mA cm-2for the CoZr-coated BiVO4photoanodes compared to that for bare BiVO4.