Catalytic hydrotreatment of triglycerides and various renewable oils into green diesel over metal–organic frameworks derived Ni@C catalyst

Triglycerides is a kind of natural oil widely existing in animals and plants, and it is also an ideal raw material for preparing biomass liquid fuel. Selectively hydrotreatment of unsaturated glyceride is an important strategy for the production of fuels and chemical feedstocks. In this work, catalytic hydrotreatment of triglycerides over Ni-based catalysts was investigated. Thus, an array of metal–organic frameworks derived Ni@C catalysts synthesized under different temperatures (350 °C, 400 °C, 450 °C) were prepared and applied for hydrotreatment of triglycerides. The highest conversion of triglycerides was 98.9% and the cracking rate could achieve 4.61% over the optimal Ni@C-BTC-400 catalyst in cyclohexane at 320 °C. The physicochemical characterizations were carried out by means of powder X-ray diffraction, scanning electronic microscopy, thermo gravimetric analyzer, N adsorption–desorption, and Raman. Based on the optimal reaction condition (320 °C, 3 h, 3.0 MPa H), five typical vegetable oils and gutter oils were selected for the hydrotreatment study to investigate the adaptability of Ni@C-BTC-400 catalyst. The result indicated that Ni@C-BTC-400 catalyst performed good universality, and could transform oil raw materials with different fatty acid carbon chain structure to desired alkanes. Furthermore, the optimal Ni@C-BTC-400 catalyst could be carried out in next two consecutive recycling runs and could also be regenerated by H for the following experiments.