Grätzel-Type TiO2 Anatase Layers as Host for Pt Single Atoms: Highly Efficient and Stable Photocatalytic Hydrogen Production

Abstract

Single atoms (SAs) represent not only a new frontier in classic heterogeneous catalysis but are also increasingly investigated as co-catalysts in photocatalytic reactions. In contrast to classic catalysis, many photocatalytic platforms require only a very low SA loading density to reach a saturated photocatalytic activity. As a result, an optimized light harvesting/carrier transport combination in the supporting semiconductor becomes the key aspect for the overall photocatalytic efficiency. In this work, it is demonstrated that Grätzel type mesoporous TiO2 layers represent an ideal host for Pt single-atoms (SAs) that allow for a highly effective photocatalytic H2 generation. Using a layer with an optimized geometry, structure, as well as Pt SA loading, a photocatalytic H2 production is achieved of up to ≈2900 µL h−1 (under irradiation at λ = 365 nm and I = 65 mW cm−2) – a performance that is far superior to previous Pt SA/TiO2 structures based on TiO2 nanotubes, nanosheets, or metal organic frameworks. Moreover, such SA/substrate combination provides a highly stable H2 production over time. The present work thus introduces the use of this classic TiO2 nanostructure as the most effective host for Pt SAs and its use for highly efficient photocatalytic H2 production from aqueous solutions.