The Effect of Platinum Single Atoms in Titania for Photocatalytic Applications

The photocatalytic effect of titania has long been studied with respect to water oxidation and hydrogen evolution. At present, the modification of this semiconducting material by platinum single atoms (Pt-SAs) represents an interesting approach that has been developed in the past decade and has given good results in the photocatalytic hydrogen evolution reaction (HER). Experimental studies have shown that the deposition of Pt-SAs on the titania surface, in aqueous systems, is a spontaneous process and can also be promoted by different reducing processes. Theoretical studies suggest that this deposition is a site-specific reaction, which occurs in oxygen vacancies on the titania surface. Under such conditions, the Pt-SAs are not in a metallic state, due to the interaction with neighbouring atoms of the substrate. This complex system can be probed using different advanced characterisation techniques, which provide a deeper understanding about the modified surface and how this modification improves the photocatalytic performance of titania.