EFFECT OF CALCINATION TEMPERATURE ON THE PROPERTIES OF SILICA-SUPPORTED Ni-Cu CATALYST FOR THE HYDROCRACKING REACTION OF USED COOKING OIL TO BIOFUEL

The hydrocracking reaction is a reaction that breaks hydrocarbon bonds from vegetable oil into shorter hydrocarbons so that they can be used as biofuel. Ni and Cu metals are quite commonly used in this reaction, where Ni metal functions as an active catalyst in the reaction, and Cu metal plays a role in increasing the stability of Ni metal from coke formation during the hydrocracking reaction. Mesoporous silica is used as a carrier for Ni and Cu metals because it has high stability and porosity. Calcination is one of the processes in the synthesis of mesoporous silica which aims to remove the template from the silica and plays a role in the formation of silica crystallinity and porosity. Changes in calcination temperature will affect the porosity and crystallinity of silica which causes differences in the distribution of Ni and Cu metals. The difference in the distribution of Ni and Cu metals affects the surface area of the active site which can influence the activity and selectivity of the catalyst in the hydrocracking reaction. This research aims to synthesize a Ni-Cu/Silica catalyst for the hydrocracking reaction of used cooking oil into biofuel. Mesoporous silica is synthesized by the hydrothermal method. Then, the Ni-Cu/Silica catalyst was synthesized by impregnating and reducing Ni and Cu metal into mesoporous silica. The Ni-Cu/Silica catalyst was then applied to the used cooking oil hydrocracking reaction to test its activity and selectivity. The results of characterization using FTIR show that the Ni-Cu/Silica catalyst has a vibration peak which indicates the presence of silanol (Si-O-Si) and siloxane (Si-OH) groups. Based on the acidity test, the SM-400, SM-500, and SM-600 catalysts have Lewis acid sites and Brondsted acid sites detected on the FTIR absorption peak with SM-500 having the highest acidity level. The XRD results show that the Ni-Cu/Silica catalyst has amorphous crystallinity and has Ni and Cu metal sites detected in the XRD diffractogram. The GSA results show that the SM-400, SM-500, and SM-600 catalysts have dominant pore sizes in the mesoporous region. The GC-MS results show that hydrocracking using a catalyst produces more product compared to hydrocracking without a catalyst and the SM-500 catalyst has the highest activity and selectivity compared to other variations of catalyst.