Synergy in Au−CuO Janus Structure for Catalytic Isopropanol Oxidative Dehydrogenation to Acetone. Issue 27 (5th May 2022)

• Record Type: Journal Article
• Authors: Guo, Meng; Ma, Peijie; Wang, Jiayi; Xu, Haoxiang; Zheng, Kun; Cheng, Daojian; Liu, Yuxi; Guo, Guangsheng; Dai, Hongxing; Duan, Erhong; Deng, Jiguang
• Is Part Of: Angewandte Chemie international edition. Volume 61:Issue 27(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-05
• Subjects: Active Sites -- Alcohol Selective Oxidation -- C−H Activation -- Gold Catalysis -- Metal/Oxide Janus Structure; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202203827
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The controlled oxidation of alcohols to the corresponding ketones or aldehydes via selective cleavage of the β‐C−H bond of alcohols under mild conditions still remains a significant challenge. Although the metal/oxide interface is highly active and selective, the interfacial sites fall far behind the demand, due to the large and thick support. Herein, we successfully develop a unique Au−CuO Janus structure (average particle size=3.8 nm) with an ultrathin CuO layer (0.5 nm thickness) via a bimetal in situ activation and separation strategy. The resulting Au−CuO interfacial sites prominently enhance isopropanol adsorption and decrease the energy barrier of β‐C−H bond scission from 1.44 to 0.01 eV due to the strong affinity between the O atom of CuO and the H atom of isopropanol, compared with Au sites alone, thereby achieving ultrahigh acetone selectivity (99.3 %) over 1.1 wt % AuCu0.75 /Al2 O3 at 100 °C and atmospheric pressure with 97.5 % isopropanol conversion. Furthermore, Au−CuO Janus structures supported on SiO2, TiO2 or CeO2 exhibit remarkable catalytic performance, and great promotion in activity and acetone selectivity is achieved as well for other reducible oxides derived from Fe, Co, Ni and Mn. This study should help to develop strategies for maximized interfacial site construction and structure optimization for efficient β‐C−H bond activation. Abstract : A unique Au−CuO Janus structure with a 0.5 nm ultrathin CuO layer was developed. The Au−CuO interfacial structure was confirmed to be extremely efficient for C−H activation; a dramatic decrease of the β‐C−H bond scission energy barrier from 1.44 to 0.01 eV due to the strong affinity between the O of CuO and H of isopropanol, compared with Au sites alone, was observed.