Non-noble metal(s)-based mesoporous catalysts are one of the promising catalysts for aqueous phase hydrodeoxygenation of lignin-derived phenols to produce hydrocarbons. In this paper, Ni/Al-SBA-15 was prepared through incipient wetness impregnation method and the performance of eugenol hydrodeoxygenation over Ni/Al-SBA-15 was studied. The effect of incipient wetness impregnant on the performance of eugenol hydrodeoxygenation over Ni/Al-SBA-15 was investigated. The materials were characterized by XRD, N 2 -sorption, TEM, FTIR, Py-FTIR, XRF and ICP-MS. In comparison with the traditional incipient wetness impregnation using water as solvent, the activity of Ni/Al-SBA-15 was significantly improved by using ethanol as solvent during the process of incipient wetness impregnation. For Ni/Al-SBA-15, the quantity of total acid was decreased after loading nickel species which was mainly due to the decrease of Lewis acid sites. The strength of Lewis acid in Ni/Al-SBA-15 prepare with ethanol as impregant was enhanced. The yields of propyl cyclohexane and propylbenzene from aqueous phase hydrodeoxygeation of eugenol over Ni/Al-SBA-15-E were increased. The super catalytic behavior of Ni/Al-SBA-15-E was attributed to the synergistic effect between the stronger Lewis acid sites and the intact framework structure of Ni/Al-SBA-15-E.
Template removing approaches can significantly impact the physiochemical properties of mesoporous molecular sieve materials. In order to better understand the relationship between template removing approaches and the properties of Ni/Al-SBA-15, four kinds of template removing approaches were introduced to remove the organic template from Al-SBA-15, respectively. The structural characteristics of these materials were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray fluorescence (XRF), powder X-ray diffraction (XRD), N 2 -sorption, Fourier transform infrared spectra (FT-IR), infrared spectra of pyridine adsorption (Py-FTIR), magic angle spinning-nuclear magnetic resonance (MAS-NMR), X-ray photoelectron spectroscopy (XPS) and gas chromatography-mass spectrometry (GC-MS). Ni/Al-SBA-15 of which the organic template was removed by two-step calcination method had the maximum specific surface area (619 m 2 /g). In contrast, Ni/Al-SBA-15 of which the organic template was removed using solvent extraction approaches had the lowest specific surface area (555 m 2 /g). The mesopore diameter of Ni/Al-SBA-15, using electric heating digestion method to remove the template, was significantly increased and the wall thickness was significantly decreased to 11.62 nm in comparison with the other samples. The selectivity of products during the process of eugenol hydrodeoxygenation was investigated. High hydrocarbons were obtained during catalytic hydrodeoxygenation over Ni/Al-SBA-15 of which the organic template was removed by using solvent extraction approaches. Compared with direct calcination process, two-step calcination was more effective in removing template and the corresponding catalyst was much more suitable for the hydrodeoxygenation process.
Li Xiangping,Liu Juping,Zhang Jianguang,Liu Bin,Ma Wenchao,Wang Chuanbin,Chen Guanyi
Lignocellulosic biomass-derived bio-oil is considered as a promising renewable biofuel. In this paper, incipient wetness impregnation method, ammonia grafting method and direct synthesis method were employed as nickel loading methods for the preparation of Ni/Al-SBA-15 catalysts. The effects of these nickel loading approaches on the structure and hydrodeoxygenation performance of Ni/Al-SBA-15 were studied. The structure of Ni/Al-SBA-15 was significantly influenced by the nickel loading methods, including the specific surface area, the pore volume, the wall thickness and so on. Nickel loading methods also affected the actual nickel content of nickel-based catalysts. Unsuccessful loading of nickel species was observed during the preparation of Ni/Al-SBA-15 using direct synthesis method. The conversion of eugenol and selectivity of products after hydrodeoxygenation in n -dodecane over Ni/Al-SBA-15 catalysts were investigated. Results showed that the conversion of eugenol nearly reached 100% for all the reaction, but the composition of product was significantly different when using different Ni/Al-SBA-15 as hydrodeoxygenation catalyst. The reaction pathway of eugenol hydrodeoxygenation in n -dodecane was also speculated in this paper. Graphic Effects of nickel loading approaches on the structure and hydrodeoxygenation performance of Ni/Al-SBA-15 were investigated. For the liquid phase hydrodeoxygenation of eugenol to hydrocarbon, catalysts prepared by ammonia grafting method exhibited the highest catalytic activity.