Synthesis of NiO/mesoporous aluminosilicate nanoparticles using natural template for green diesel production: the effect of Si/Al ratio

Mesoporous aluminosilicate nanoparticles synthesized using metakaolin with Sapindus rarak (Spr) extract as a natural template were impregnated with 5 % NiO to convert waste cooking oil into green diesel. The Si/Al molar ratios of mesoporous aluminosilicate were varied from 30 to 60 to study the effect of acidity. NiO was well dispersed on the aluminosilicate, with sizes ranging from 12.5 to 16.6 nm. NiO/M50 possesses cylindrical pores with a high surface area (152 m²/g) and a favorable V_meso/V_micro ratio (833.3), which facilitates the mass transfer and diffusion of reactants. NiO/M50 achieved ∼96 % selectivity to C8-C20 hydrocarbons. Selectivity for C15-C17 hydrocarbons is slightly reduced at lower Si/Al ratios due to cracking reactions to form short-chain hydrocarbons that occur on highly acidic catalysts. NiO/Mx catalysts change the course of reaction from undergoing thermal cracking to deoxygenation via decarboxylation routes.