Activity enhancement of Ru/CeO2 for N-alkylation of amines with alcohols through tailoring metal-support interaction

• Published in: Journal of catalysis 2024-01, Vol.429, p.115241, Article 115241
• Main Authors: Zou, Yiwen, Dong, Lin, Yan, Siyang, Liu, Jiaxu, Mu, Lili, Li, Licheng, Hu, Yue, Qi, Haifeng, Mao, Shanjun, Chen, Zupeng
• Format: Article
• Language: English
• Subjects: Ceria; Metal−support interaction; Morphological effect; N-alkylation reaction; Ru nanoparticles
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2023.115241

[Display omitted] •Highly dispersed Ru nanoparticles were loaded on three kinds of CeO2 with different morphologies (rod, cube, and octahedron).•The Ru/CeO2-R (rod) catalyst possesses much more oxygen vacancies and Ru0 than other Ru/CeO2 samples.•The Ru/CeO2-R (rod) catalyst shows high activity and excellent stability for the N-alkylation of amines with alcohols via the transfer hydrogenation path.•The Ru nanoparticles with a metallic state promote the dehydrogenation of the hydroxyl group and hydrogenation of imines.•CeO2-R with rich oxygen vacancies facilitates the adsorption and activation of benzyl alcohol. Efficient and selective N-alkylation of amines with alcohols via transfer hydrogenation is of great significance but extremely challenging. Here, we report the production of N–benzylaniline (BZA) from benzyl alcohol and aniline over various fine-shaped Ru/CeO2 catalysts. The Ru/CeO2–R (rod) catalyst exhibits the highest catalytic activity among all catalysts, in which the yield of BZA reaches up to 88% with complete conversion, significantly higher than that of Ru/CeO2-C (cube, 52%) and Ru/CeO2-O (octahedron, 32%). Extensive experimental investigations disclose that Ru nanoparticles with a metallic state promote the dehydrogenation of the hydroxyl group and hydrogenation of imines, while the CeO2–R with rich oxygen vacancies facilitates the adsorption and activation of reactants. Furthermore, kinetic studies and time-resolved operando dual-beam Fourier transform infrared spectroscopy analysis confirms the transfer hydrogenation pathway, in which the benzyl alcohol is firstly dehydrogenated to benzaldehyde, followed by spontaneously reacting with aniline, and finally transforms into the N-benzylaniline rapidly.