Boosting bio-lipids deoxygenation via tunable metal-support interaction in nickel/ceria-based catalysts

• Published in: Fuel (Guildford) Vol. 322; p. 124027
• Main Authors: Fu, Lin, Liu, Zhaoxin, Li, Xin, Li, Yongfei, Yang, Houyi, Liu, Yuejin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.08.2022; Elsevier BV
• Subjects: Acidity; Alkanes; Aluminum oxide; Ammonia; Catalysts; Catalytic activity; Cerium oxides; Coke; Cooking; Cooking oils; Covalent bonds; Deactivation; Deoxygenation; Evaporation; Hydrocarbons; Lipids; NiCeAl-EISA; Nickel; Niδ+-OV-CeOx interfacial site; Oxygen vacancies; Porosity; Self-assembly; Sintering (powder metallurgy); Surface properties; Tunable SMSI; X ray photoelectron spectroscopy; Oxygen vacancies; Niδ+-OV-CeOx interfacial site; Tunable SMSI; Deoxygenation; NiCeAl-EISA
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2022.124027

[Display omitted] •Mesoporous Ni/CeO2-Al2O3 catalyst with high CeO2 loading (≥20 wt%) was facilely prepared by one-pot EISA method.•Well-dispersed CeO2 particles are capable for exposing more oxygen vacancies and switching SMSI from Ni-Al2O3 to Ni-CeO2.•Increasing CeO2 particles dispersion helps to increase catalyst total acidity and simultaneously decrease catalyst strong acidity.•Combining enhanced porosity and tunable SMSI, NiCeAl-EISA catalyst presents excellent resistance to aggregation and coke.•NiCeAl-EISA catalyst afforded an n-C11 yield of 98.7%, and remained stable with 92.2% n-C11 yield after 11 consecutive runs. Ni-catalysts usually experienced quick deactivation during bio-lipids deoxygenation due to metal sintering and coke. Here we prepared a series of Ni/CeO2-Al2O3 catalysts, denoted as NiCeAl-EISA, NiCeAl-WI and NiCeAl-CP, prepared by evaporation-induced self-assembly (EISA), wetness impregnation (WI), co-precipitation (CP) methods, respectively, aiming at tuning metal-support interaction (MSI) in Ni/CeO2-Al2O3 catalysts for the deoxygenation of bio-lipids to hydrocarbons. The porosity and surface properties of the catalysts are systematically studied by BET, XRD, H2-TPR, HR-TEM, FT-IR, O2-TPD, NH3-TPD, RPR, Py-FTIR, XPS and in situ XPS. The NiCeAl-EISA catalyst afforded 92.2% n-C11 yield at full methyl laurate conversion, and efficiently deoxygenated different FAMEs, yielding corresponding alkanes yields of 97.8% (n-C9), 96.4% (n-C13), 94.3% (n-C15) and 92.9% (n-C17). The TOFs were calculated as 426–719, 241–343 and 148–243 h−1 for NiCeAl-EISA, NiCeAl-WI and NiCeAl-CP catalysts, respectively. Jatropha oil and waste cooking oil were also converted into liquid alkanes (C13-18) with a total yield of 95.4% and 93.7%, respectively. The NiCeAl-EISA catalyst exhibits superior catalytic activity and remained stable with 92.2% n-C11 yield after 11 consecutive runs, as compared with NiCeAl-WI and NiCeAl-CP. This significant increase in catalyst activity and stability is closely correlated with the tunable SMSI of Ni/CeO2-Al2O3 catalyst, which facilely forms abundant oxygen vacancies and interfacial sites (Niδ+-OV-CeOx). This suppresses strong Ni-Al interaction, thus exposing more active and robust Ni sites to promote R-COOH → R-CHO reduction to produce more alkanes. The weakened Ni-Al interaction also reduces the strong acidity and consequently inhibits the coke formation and simultaneously restrains C–C bond cleavage of hydrocarbons.