Nickel-Rich Carbon Sheet Derived from Ni-NH2–BDC Catalyzes Microalgal Biodiesel into Biojet Fuel under CO2 Atmosphere

Abstract

To address the challenges of low utilization of active sites and poor thermal stability of catalysts in the conversion of microalgal biodiesel into biojet fuel under CO2 atmosphere, a nickel-rich carbon sheet catalyst was synthesized through partial pyrolysis of a nickel-based aminoterephthalic acid framework (Ni-NH2–BDC) to enhance conversion rate and product selectivity. Because the specific surface area of Ni-NC-500 derived from pyrolyzed Ni-NH2–BDC at 500 °C increased from 20.866 to 304.337 m2/g, more generated Ni0 active sites (33.69%) strengthened the deoxidation of methyl palmitate (a typical composition of microalgal biodiesel). Compared with Ni-NH2–BDC, the total acid of Ni-NC-500 has significantly increased, reaching 58.485 mmol/g, which will promote C–C bond breaking. The large amounts of pyridine nitrogen (N-6, 39.98%) and pyrrole nitrogen (N-5, 60.13%) present in Ni-NC-500 can significantly enhance the catalytic performance. Therefore, the conversion rate of methyl palmitate and the selectivity for jet-fuel range (C8–C16) products increased to 96.28 and 84.69%, respectively.