Bo Chen,Qing-Pan Du,Zhi-Jun Diao,Hong Yuan,Jia-Meng He,Yi-Qing Xie,Xiao-Ran Wang,Yu Wang
Hydrogenation upgrading is an effective technique that lowers the oxygen content of bio-oil with the aim of improving its quality. In order to fabricate a series of Ru-based catalysts for the hydrodeoxygenation of bio-oil, several all-silica supports with different pore sizes are synthesized and modified with Al and Cs in this work. The physical morphology and electronic structure of the catalysts are characterized using multiple techniques including X-ray diffraction, in-situ pyridine adsorption infrared spectroscopy, in-situ diffuse reflectance Fourier transform infrared spectroscopy , Raman spectroscopy , CO 2 temperature-programmed desorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy , X-ray photoelectron spectroscopy and N 2 physical adsorption-desorption testing. Phenol , guaiacol , anisole and o-cresol are selected as model compounds to investigate the hydrodeoxygenation reactivity of the catalysts. The results reveal that there is a strong linear correlation between the pore size of the catalysts and the rates of the hydrogenation and hydrodeoxygenation of phenol. Importantly, both the oxygen vacancy density and relative content of Brønsted and Lewis sites (B/L) of the catalysts can be greatly increased by Cs modification, which further linearly promotes the hydrodeoxygenation activity of the catalysts. In addition, the in-situ infrared spectroscopy results show that the catalysts modified by Al and Cs heterolytically cleave H 2 to supply H + for the reaction. This work presents a novel approach for fabricating catalysts employed in the hydrotreatment process of bio-oil.
The development of non-noble metal catalysts for gas-phase propylene epoxidation with H2/O2remains challenging due to their inadequate activity and stability. Herein, we report a Cs+-modified Ni/TS-1 catalyst (9%Ni-Cs/TS-1), which exhibits unprecedented catalytic performance, giving a state-of-the-art PO formation rate of 382.9 gPO·kgcat−1·h−1with 87.8% selectivity at 200 °C. The catalyst stability was sustainable for 150 h, far surpassing reported Ni-based catalysts. Ni/TS-1 exhibited low catalytic activity. However, the Cs modification significantly enhanced the performance of Ni/TS-1. Furthermore, the intrinsic reason for the enhanced performance was elucidated by multiple techniques such as XPS, N2physisorption, TEM,29Si NMR, NH3-TPD-MS, UV–vis, and so on. The findings indicated that the incorporation of Cs+markedly boosted the reduction of Ni, enhanced Ni0formation, strengthened Ni-Ti interactions, reduced acid sites to inhibit PO isomerization, improved the dispersion of Ni nanoparticles, reduced particle size, and improved the hydrophobicity of Ni/TS-1 to facilitate propylene adsorption/PO desorption. The 9%Ni-Cs/TS-1 catalyst demonstrated exceptional performance characterized by a low cost, high activity, and long-term stability, offering a viable alternative to Au-based systems.
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