Metal Supported Metal Oxide Catalysts for Hydrogen Peroxide Production Via Water Splitting

The two-electron water oxidation reaction (WOR) has drawn recent attention as an efficient, simple method of producing on-site hydrogen peroxide through electrochemical water splitting. However, finding electrocatalysts with high activity and stability in the reaction’s harsh oxidizing environment is challenging. This is made especially difficult due to the competing four-electron and one-electron WOR, which necessitate a catalyst material with high selectivity towards the hydrogen peroxide production pathway. Here, we utilize metal/metal oxide coupling interactions to tune metal oxide catalysts to be active for 2 e - WOR via the creation of a Mott-Schottky junction. Metal/metal oxide interactions have been well studied for supported metal catalysts, but their behavior has been less investigated for catalysts where the metal oxide provides the active sites, called inverse catalysts. In this case, the difference in work functions between the metal support and metal oxide semiconductor catalyst drives electron transfer between the two, facilitating electronic interactions which can modulate the binding energy of reaction intermediates at the interface and thus tune the catalytic ability of the metal oxide. In this work, we investigate a variety of metal oxide catalyst and metal support materials and find that a thin layer of indium tin oxide (ITO) supported by a layer of platinum (Pt) has excellent catalytic ability towards 2 e - WOR. The activity, selectivity, and stability of the ITO/Pt catalyst shows significant improvement over the unsupported ITO catalyst and yields hydrogen peroxide production rates greater than those reported in literature using other standard catalysts for this reaction. This method of catalyst engineering also provides a future pathway to create new catalysts for this electrochemical reaction.