Modified Ni-Based Metal–Organic Frameworks (Ni-BTC) with High Deoxygenation and Cracking Ability for Production of a Jet Fuel-Range Hydrocarbon Blend at a Low Catalyst Dosage
Yang Xu, Hao Guo, Yuxiang Mao, Lei Qian, Weijuan Yang, Jun Cheng
Abstract
To enhance deoxygenation and cracking performance of microalgal biodiesel to produce a jet fuel-range hydrocarbon blend, an efficient Ni-carbon composite was prepared by pyrolyzing Ni-based metal–organic frameworks (Ni-1,3,5-benzenetricarboxylate, Ni-BTC) for catalytic conversion with a substantially reduced catalyst dosage. Coordinated Ni ions in the Ni-BTC precursor were converted into highly active Ni nanoparticles due to catalyst pyrolysis, while an increased specific surface area of the catalyst facilitated mass transfer in microalgal biodiesel conversion. X-ray absorption fine structure analysis confirmed the formation of Ni–Ni active sites, while density functional theory calculations revealed that the C═C bond was the initial site for the cracking reaction of long-chain fatty acids. The selectivity of jet-fuel-range products in methyl palmitate conversion over the Ni@C 500 (Ni-BTC pyrolyzed at 500 °C) catalyst increased to 71.46% with a substantially reduced catalyst dosage (the mass ratio of catalyst to reactant was 1:200). The Ni@C 500 catalyst exhibited excellent performance with high selectivity (71.6%) and conversion efficiency (97.46%) in deoxygenation and cracking of microalgal biodiesel for jet fuel-range hydrocarbon blend production.