Operando X-ray absorption spectroscopy investigation of photocatalytic hydrogen evolution over ultradispersed Pt/TiO2 catalysts
Photocatalytic hydrogen generation from water or oxygenates is foreseen as a sustainable energy production route. In spite of recent performance achievements through Pt particle downsizing, knowledge of the prototypical Pt/TiO2 photocatalyst operation mechanism, in particular the electronic state an...
| Autores: | , , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/336274 |
| Acceso en línea: | https://hdl.handle.net/2117/336274 https://dx.doi.org/10.1021/acscatal.0c03464 |
| Access Level: | acceso abierto |
| Palabra clave: | Hydrogen Photocatalysis Photocatalytic hydrogen production Single-atom catalysis Pt/TiO2 Operando spectroscopy XAS Hidrogen Fotocatàlisi Àrees temàtiques de la UPC::Enginyeria química Àrees temàtiques de la UPC::Enginyeria química::Química física |
| Sumario: | Photocatalytic hydrogen generation from water or oxygenates is foreseen as a sustainable energy production route. In spite of recent performance achievements through Pt particle downsizing, knowledge of the prototypical Pt/TiO2 photocatalyst operation mechanism, in particular the electronic state and the stability of the Pt phase under reaction conditions, remains limited. We have investigated atomically dispersed Pt/TiO2 catalysts by pre-/postreaction scanning transmission electron microscopy and operando X-ray absorption spectroscopy–mass spectrometry under gas-phase ethanol dehydrogenation conditions under ultraviolet–visible light irradiation. The catalysts were prepared by a simple impregnation method on two types of commercial titania. While the general effect of the reaction on initially fully oxidized (PtIV) single-atom catalysts (SACs) is Pt reduction and aggregation, this combined phenomenon can be inhibited in two manners. First, when it is supported on high-surface-area anatase, the Pt SAC retains an intermediate oxidation state, and its clustering is limited to Pt dimers and trimers. Second, with the same support, a mild reducing pretreatment generates, through the formation of Pt–Ti bonds, near-neutral and ultradispersed Pt species (from single atoms to nanometric clusters) with the highest stability and activity in photocatalytic hydrogen evolution. |
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