Acid-etched Pt/Al-MCM-41 catalysts for fuel production by one-step hydrotreatment of Jatropha oil

Abstract

Effective catalysts are indispensable for the preparation of fuel components from vegetable oils via the one-step hydrothermal method. In this study, the Pt/MCM-41 catalysts were prepared by etching with sulfuric acid, citric acid, or hydrochloric acid. The performance of the obtained Pt/MCM-41 catalysts for the hydrothermal treatment of vegetable oils was evaluated in a fixed-bed reactor using Jatropha oil as a model raw material (temperature = 360°C, liquid hourly space velocity = 1 h−1, hydrogen–oil ratio = 1000, and hydrogen pressure = 4 MPa). The modified catalysts were characterized using X-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller analysis, X-ray fluorescence spectrometry, temperature-programmed desorption of NH3, CO chemisorption, and pyridine adsorption infrared spectroscopy, respectively. Furthermore, the selectivity of various fuel components, including C8–C16 alkanes, C8–C16 iso-alkanes, C8–C16 arenes, and C17–C18 alkanes, were analyzed based on the catalyst characteristics. Acid etching was found to decrease the surface area of Al-MCM-41 but increase the amount of acid sites, and among these acids, citric acid was proved as the priority additives, with better catalytic performance. Moreover, this catalyst exhibited the best conversion and the highest C8–C16 and C17–C18 selectivities.