Ti-doped CeO2 Stabilized Single-Atom Rhodium Catalyst for Selective and Stable CO2 Hydrogenation to Ethanol

Abstract

Development of effective and stable catalysts for CO₂ hydrogenation into ethanol remains a challenge. Herein, we report that Rh₁ /CeTiO_x single-atom catalyst constructed by embedding monoatomic Rh onto Ti-doped CeO₂ support has shown a super high ethanol selectivity (≈99.1 %), record-breaking turnover frequency (493.1 h^-1 ), and outstanding stability. Synergistic effects of Ti-doption and monoatomic Rh contribute to this excellent catalytic performance by firstly facilitating oxygen vacancies formation to generate oxygen-vacancy-Rh Lewis-acid-base pairs, which favor CO₂ adsorption and activation, cleavage of C-O bonds in CH_x OH* and COOH* into CH_x * and CO* species, subsequent C-C coupling and hydrogenation into ethanol, and secondly generating strong Rh-O bond by Ti-doping-induced crystal reconstruction, which contributes to striking stability. This work highlights the importance of support elaborating regulation for single-atom catalyst design to substantially improve the catalytic performance.

Keywords: CO2 Hydrogenation; Ethanol; Rh1/CeTiOx; Single-Atom Catalyst; Stability.