Pt single-atom-layer ensembles on TiO2 for direct dehydrogenation of methanol to hydrogen and methyl formate

[Display omitted] •Surface oxygen vacancies on TiO2 influenced Pt distribution states.•Pt distribution and oxygen vacancies affect catalytic performance.•Vacancies adsorb methanol, and H2 is generated on Pt single atoms.•Catalyst with four or five Pt atoms showed exceptional photocatalysis. Controlling the distribution state of active components to regulate the photocatalytic performance of green hydrogen production from methanol, while achieving zero carbon emissions, poses a significant challenge. In this study, we synthesized photocatalysts with varying distribution states of Pt single atoms on TiO2 by modulating the surface oxygen vacancies. The photocatalytic performance of these catalysts in the direct dehydrogenation of methanol to hydrogen and methyl formate was assessed at room temperature. Our findings revealed that the number of surface oxygen vacancies on TiO2 influenced the distribution states of Pt, including single Pt atoms, Pt dimers, Pt trimers, Pt ensembles with approximately five atoms, and Pt ensembles with more than ten single-layer atoms. These Pt species were anchored to surface oxygen vacancies on TiO2 in the form of Pt2+. The distribution states of Pt and the remaining oxygen vacancies significantly impact light absorption and electron transfer properties, ultimately influencing the catalytic performance of the photocatalysts. Notably, the Pt/TiO2-VO2 catalyst, characterized by a spatial arrangement of five Pt atoms, demonstrated exceptional photocatalytic performance in the reaction, primarily attributable to the presence of favorable active sites facilitating methanol adsorption and dissociation in the vicinity of the Pt ensemble, along with the notably high efficiency of hydrogen generation on the Pt ensemble. The vacancies served as active sites for the adsorption and dissociation of methanol molecules, while the Pt single-atom-layer ensembles were identified as effective active sites for H2 generation. This study provides valuable insights for the design and preparation of efficient photocatalysts for the direct dehydrogenation of methanol to hydrogen and methyl formate through photocatalysis.