Abstract
In this study, the catalytic activity of bifunctional SiO(2)/Zr catalysts prepared by template and chelate methods using potassium hydrogen phthalate (KHF) for crude palm oil (CPO) hydrocracking to biofuels was investigated. The parent catalyst was successfully prepared by the sol-gel method, followed by the impregnation of zirconium using ZrOCl(2)·8H(2)O as a precursor. The morphological, structural, and textural properties of the catalysts were examined using several techniques, including electron microscopy energy-dispersive X-ray with mapping, transmission electron microscopy, X-ray diffraction, particle size analyzer (PSA), N(2) adsorption-desorption, Fourier transform infrared-pyridine, and total and surface acidity analysis using the gravimetric method. The results showed that the physicochemical properties of SiO(2)/Zr were affected by different preparation methods. The template method assisted by KHF (SiO(2)/Zr-KHF2 and SiO(2)-KHF catalysts) provides a porous structure and high catalyst acidity. The catalyst prepared by the chelate method assisted by KHF (SiO(2)/Zr-KHF1) exhibited excellent Zr dispersion toward the SiO(2) surface. The modification remarkably enhanced the catalytic activity of the parent catalyst in the order SiO(2)/Zr-KHF2 > SiO(2)/Zr-KHF1 > SiO(2)/Zr > SiO(2)-KHF > SiO(2), with sufficient CPO conversion. The modified catalysts also suppressed coke formation and resulted in a high liquid yield. The catalyst features of SiO(2)/Zr-KHF1 promoted high-selectivity biofuel toward biogasoline, whereas SiO(2)/Zr-KHF2 led to an increase in the selectivity toward biojet. Reusability studies showed that the prepared catalysts were adequately stable over three consecutive runs for CPO conversion. Overall, SiO(2)/Zr prepared by the template method assisted by KHF was chosen as the most prominent catalyst for CPO hydrocracking.