Defect-rich BN-supported Cu with superior dispersion for ethanol conversion to aldehyde and hydrogen

• Published in: Chinese journal of catalysis Vol. 43; no. 4; pp. 1092 - 1100
• Main Authors: Cheng, Shi-Qun, Weng, Xue-Fei, Wang, Qing-Nan, Zhou, Bai-Chuan, Li, Wen-Cui, Li, Ming-Run, He, Lei, Wang, Dong-Qi, Lu, An-Hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2022
• Subjects: Boron nitride nanosheet; Copper; Ethanol dehydrogenation; In situ DRIFT; Superior dispersion; Boron nitride nanosheet; In situ DRIFT; Copper; Superior dispersion; Ethanol dehydrogenation
• ISSN: 1872-2067; 1872-2067
• DOI: 10.1016/S1872-2067(21)63891-3

Copper-based heterogeneous catalysts commonly exhibit uncontrolled growth of copper species under reaction conditions because of the low Hüttig temperature (surface mobility of atoms) and Tamman temperature (bulk mobility) for copper at just 134 and 405 °C, respectively. Herein, we report the use of defect-enriched hexagonal boron nitride nanosheets (BNSs) as a support to anchor the Cu species, which resulted in superior dispersion of the Cu species. The obtained Cu/BNS catalyst was highly stable for ethanol dehydrogenation, with a high selectivity of 98% for producing acetaldehyde and an exceptionally high acetaldehyde productivity of 7.33 gAcH gcat–1 h–1 under a weight hourly space velocity of 9.6 gEtOH gcat–1 h–1. The overall performance of our designed catalyst far exceeded that of most reported heterogeneous catalysts in terms of the stability of the Cu species and the yield of acetaldehyde in this reaction. The hydroxyl groups at the defect edges of BNS were responsible for the stabilization of the copper species, and the metal-support interaction was reinforced through charge transfer, as evidenced by coupling atomic resolution images with probe molecule infrared spectroscopy and X-ray photoelectron spectroscopy. A designed in situ diffuse reflectance infrared Fourier transform spectroscopy study of ethanol/acetaldehyde adsorption further revealed that Cu/BNS favored ethanol adsorption while suppressing acetaldehyde adsorption and further side reactions. This study demonstrates a new method for designing highly dispersed Cu-based catalysts with high durability. Copper-based heterogeneous catalysts possessing well-dispersed Cu species were prepared using defect-enriched hexagonal boron nitride nanosheets as supports. The fabricated catalysts showed exceptionally stable performance and high activity and yield in the ethanol dehydrogenation reaction.