Preparation of rich hydrocarbon biofuels from cracking of waste cooking oil by CaO@Zn-KIT-6

The preparation of biofuel from bio-oils is of great importance to the development of renewable energy and to alleviate environmental pollution problems. In this work, acidic mesoporous silica Me-KIT-6 (Me = Zn, Al, Zr, Sn, Mn) were prepared and coated with basic metal oxides, and the CaO@Me-KIT-6 catalyst was obtained, and tested in the catalytic cracking reaction of waste oils and fats. The structure of the catalyst was characterized by X-ray diffraction, N2 physical adsorption and transmission electron microscopy (TEM), the acidity/basicity was characterized by chemisorption (NH3-TPD/CO2-TPD), and the structure-performance relationship in waste cooking oil catalytic cracking was investigated in detail. The results showed that CaO@Zn-KIT-6 catalyst had a good catalytic performance with a liquid biofuel yield of 66.30% and an acid value of about 23.35 mg KOH/g. The carbon distribution of the liquid biofuel concentrated in the range of C13-C18 with 67.80% of hydrocarbon products. The synthesized core-shell catalysts displayed multifunctional role resulting from tailored acid-base synergy.