Atomic-Scale Observation of the Metal-Promoter Interaction in Rh-Based Syngas-Upgrading Catalysts.

Authors :: Huang X
Teschner D
Dimitrakopoulou M
Fedorov A
Frank B
Kraehnert R
Rosowski F
Kaiser H
Schunk S
Kuretschka C
Schlögl R
Willinger MG
Trunschke A
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2019 Jun 24; Vol. 58 (26), pp. 8709-8713. Date of Electronic Publication: 2019 May 30.
Publication Year :: 2019
Abstract: The direct conversion of syngas to ethanol, typically using promoted Rh catalysts, is a cornerstone reaction in CO <subscript>2</subscript> utilization and hydrogen storage technologies. A rational catalyst development requires a detailed structural understanding of the activated catalyst and the role of promoters in driving chemoselectivity. Herein, we report a comprehensive atomic-scale study of metal-promoter interactions in silica-supported Rh, Rh-Mn, and Rh-Mn-Fe catalysts by aberration-corrected (AC) TEM. While the catalytic reaction leads to the formation of a Rh carbide phase in the Rh-Mn/SiO <subscript>2</subscript> catalyst, the addition of Fe results in the formation of bimetallic Rh-Fe alloys, which further improves the selectivity and prevents the carbide formation. In all promoted catalysts, Mn is present as an oxide decorating the metal particles. Based on the atomic insight obtained, structural and electronic modifications induced by promoters are revealed and a basis for refined theoretical models is provided.<br /> (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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