Adsorption and activation of CO2 on Pt/CeOx/TiO2(110): Role of the Pt-CeOx interface

Description

The adsorption and dissociation of CO2 on TiO2(110), CeOx/TiO2(110) and Pt/CeOx/TiO2(110) surfaces has been examined using Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS). The substrates under study exhibited different degrees of complexity which were tested for the binding of the adsorbate and the cleavage of C-O bonds. The surfaces were prepared by depositing CeOx (0.1 ML) onto TiO2(110) to form a mixed oxide support, onto which Pt nanoparticles (0.2 ML) were deposited. This configuration yields a complex set of in- terfaces between metal and oxides and we have systematically titrated the active role of each component (Pt 4f, Ce 3d and Ti 2p regions) and the arising surface intermediates (C 1 s and O 1 s regions). CO2 barely bonds to stoichiometric TiO2(110). It heals oxygen vacancies of this oxide surface (CO2,gas → COgas + Oa) and does not form stable carbonates. A stable carbonate was seen upon adsorption of CO2 on CeOx/TiO2(110) and on this type of substrate the adsorbate also removed O vacancies leading to the oxidation of Ti3+and Ce3+ sites. Pt nano- particles dispersed on CeOx/TiO2(110) were highly effective for the binding and dissociation of CO2, with the formation of CO3, CO, C and CHx species on the Pt/CeOx/TiO2(110) system. The results of theoretical calcula- tions based on density-functional theory (DFT) show that Pt/CeOx/TiO2(110) binds CO2 much stronger than surfaces of bulk platinum {(111), (100), (110)} or other late transition metals. On a Pt-CeOx interface, the molecule adsorbs with a bent configuration (~130◦ O-C-O bond angle) and with a substantial elongation (~ 0.1 Å) of the C-O bonds, facilitating its transformation into high value chemicals.

Abstract

U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences and Catalysis Science Program-DE-SC0012704

Abstract

Office of Science by Brookhaven National Laboratory-DE-SC0012704

Abstract

Ministerio de Ciencia, Innovación y Universidades de España y fondos FEDER de la UE-PID2019-106871GB-I00

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