open access

https://hdl.handle.net/2115/92977

Dynamic Behavior of Intermediate Adsorbates to Control Activity and Product Selectivity in Heterogeneous Catalysis : Methanol Decomposition on Pt/TiO2(110)

英語

2023-08-16

American Chemical Society

Journal of the American Chemical Society

145(36)

19953-19960

Dynamic behavior of intermediate adsorbates, such as diffusion, spillover, and reverse spillover, has a strong influence on the catalytic performance in oxide-supported metal catalysts. However, it is challenging to elucidate how the intermediate adsorbates move on the catalyst surface and find active sites to give the corresponding products. In this study, the effect of the dynamic behavior of methoxy intermediate on methanol decomposition on a Pt/TiO2(110) surface has been clarified by combination of scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density functional theory (DFT) calculations. The methoxy intermediates were formed by the dissociative adsorption of methanol molecules on Pt nanoparticles at room temperature followed by spillover to the TiO2(110) support surface. TPD results showed that the methoxy intermediates were thermally decomposed at >350 K on the Pt sites to produce CO (dehydrogenation) and CH4 (C-O bond scission). A decrease of the Pt nanoparticle density lowered the activity for the decomposition reaction and increased the selectivity toward CH4, which indicates that the reaction is controlled by diffusion and reverse spillover of the methoxy intermediates. Time-lapse STM imaging and DFT calculations revealed that the methoxy intermediates migrate on the five-fold coordinated Ti (Ti-5c) sites along the [001] or [1 (1) over bar 0] direction with the aid of hydrogen adatoms bonded to the bridging oxygens (O-br) and can move over the entire surface to seek and find active Pt sites. This work offers an in-depth understanding of the important role of intermediate adsorbate migration in the control of the catalytic performance in oxide-supported metal catalysts.

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/articlesonrequest/AOR-BBBCDHY4WMSNPTATZ6GX

0002-7863