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Journal articles
Zr(IV) surface sites determine CH3OH formation rate on Cu/ZrO2/SiO2 - CO2 hydrogenation catalysts
Abstract : Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(IV) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(IV) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(IV) surface sites that stabilizes reaction intermediates.
https://hal-ifp.archives-ouvertes.fr/hal-02409771
Contributor : Nadine Couëdel Connect in order to contact the contributor
Submitted on : Friday, December 13, 2019 - 3:29:59 PM
Last modification on : Thursday, May 27, 2021 - 1:54:07 PM
Contributor : Nadine Couëdel Connect in order to contact the contributor
Submitted on : Friday, December 13, 2019 - 3:29:59 PM
Last modification on : Thursday, May 27, 2021 - 1:54:07 PM
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