Pt single atoms dispersed in a hybrid MOFox-in-nanotube structure for efficient and long-term stable photocatalytic H2 generation

Abstract

Atomically dispersed Pt single atoms (SAs) have been reported to be a highly effective co-catalyst on TiO₂ for photocatalytic H₂ generation. Many TiO₂ supports have been explored for hosting Pt SAs. Particularly 1D titania hosts allow for an optimized light and charge carrier management. But, attached Pt SAs often suffer from agglomeration during the photocatalytic process. In this context, titania-based metal–organic frameworks (MOFs), such as MIL-125, have attracted wide attention, as they provide stable anchoring sites for Pt SAs. To combine the beneficial features of the 1D TiO₂ morphology with the SA stability, we introduce here a hierarchical structure, where the Pt SAs are dispersed in MOF-derived porous oxide features that are embedded in aligned anodic TiO₂ nanotubes. This hybrid structure is intrinsically (within the nanotubes) synthesized and combines the excellent light harvesting and carrier transport properties of titania nanotubes with the beneficial features of MOF. As a result of this synergy, we obtain not only a high photocatalytic H₂ evolution efficiency but most importantly a remarkably long-term stability of H₂ evolution under UV light (365 nm) or simulated solar light (AM 1.5).