Study of metal sequenced spray impregnation method towards Co-Mo/γ-Al2O3 catalytic performance in hydrotreating of used coconut oil to liquid biohydrocarbon

Abstract

A series of bifunctional catalyst CoMo on γ-Al₂O₃ have been successfully prepared using the spray impregnation (dry impregnation), with the variation in the metal sequence (Co-Mo and Mo-Co) and metal impregnation time gap (1-h, 24-h, and simultaneous). XRF indicated that the developed method causes a minimal amount of metal loss during the impregnation process. XRD shows that 24-h treatment reduces crystallinity compared to the 1-h and simultaneous catalysts. Co and Mo existed as CoAl₂O₄, CoO, and MoO₃ as reported by XANES and XPS. The preparation technique signified the catalyst's acidity and surface area. The Co-Mo/γ-Al₂O₃ 24H has a high surface area (118.32 m² g⁻¹), with a pore volume of 0.22 cm³ g⁻¹, and a pore diameter of 7.48 nm. It has a high proportion of weak acid sites (41.32 %) which is crucial to perform HDO reactions. Co-Mo/γ-Al₂O₃ 24H showed high catalytic activity (40.32 wt% liquid product) and selectivity (85.61 % of biogasoline and 9.75 % of diesel fractions) from the hydrotreatment. Kimi@UGM2010.