writer：Bao, JH (Bao, Jiehua) [1] ; Zhou, YM (Zhou, Yuming) [1] ; Zhang, YW (Zhang, Yiwei) [1] ; Wang, YY (W
keywords：Ni catalystsCeO2Al-Mg oxide spheresPyridineDehydrogenative homo-coupling
source：期刊
Issue time：2020年
In this study, we synthesized a series of Ni-based catalysts with different CeO2 contents (0, 1, 2, 5 and 10 wt%) anchoring on the Al-Mg oxide spheres (AMO) with three-dimensional hollow flower-like structure. The triethoxyoctylsilane (TEOOS) and polyvinylpyrrolidone (PVP) were selected as effective modified reagents to introduce hydrophobic functionality on the surface of AMO and Ni-CeO2 nanoparticles, respectively, for controllable anchoring Ni-CeO2 nanoparticles on AMO by hydrophobic interaction driving mechanism. The effects of CeO2 content on the texture, dispersion of Ni species, the reducibility of Ni2+, surface electronic states and acidity were investigated in detail. The Ni-5CeO(2)/AMO was found to achieve the highest 2,2''-bipyridine selectivity of 90.6% and maximum turnover number (TON) of 8611, specifically. Moreover, the Ni-5CeO(2)/AMO exhibits superior stability, maintaining 89% of 2,2''-bipyridine yield after 6 runs, due to the mitigated nickel leaching and promotion of the desorption of 2,2''-bipyridine. Furthermore, with the help of DFT calculations, a possible reaction mechanism was discussed and illustrated. (c) 2020 Elsevier Inc. All rights reserved.