Role of the Ni/Mo bimetal ratio in regulating structural and bifunctional properties of pillared bentonite for hydrocracking of palm oil decanter cake

Abstract

Utilization of biomass waste as a renewable energy source is a promising strategy to reduce dependence on fossil fuels while supporting sustainable waste management. Palm oil decanter cake (PODC), a major by-product of the palm oil industry, contains a high lipid fraction and is therefore a promising feedstock for hydrocracking into liquid biofuels. In this study, NiMo bimetallic catalysts supported on Al-pillared bentonite (BPILC) were synthesized via wet co-impregnation with varying Ni/Mo ratios and applied for PODC hydrocracking. The catalysts were characterized using XRD, FTIR, SEM–EDX, XPS, BET–BJH, TGA, and acidity analyses. The results showed that the Ni/Mo ratio strongly affected the pore structure, metal dispersion, acidity, and metal–support interactions of the catalysts. Ni15Mo5/BPILC exhibited the most favourable textural characteristics, including the largest average pore diameter (16.43 nm), highest pore volume (0.5939 cm³/g), and relatively higher acidity (3.19 mmol/g), together with more accessible Lewis and Brønsted acid sites. These properties enhanced reactant accessibility and promoted more effective hydrocracking of PODC-derived heavy hydrocarbons. Ni15Mo5/BPILC achieved the highest PODC conversion of 72% and promoted selectivity toward light hydrocarbon fractions, with approximately 62% of the liquid products distributed within the C₅–C₁₆ range. These findings demonstrate that optimising the Ni/Mo ratio is important for controlling the structural and bifunctional properties of pillared clay-based catalysts for biomass hydrocracking applications.