Hydrodeoxygenation of non-edible bio-lipids to renewable hydrocarbons over mesoporous SiO2-TiO2 supported NiMo bimetallic catalyst

Ni-catalysts are promising candidate for fatty acid hydrodeoxygenation (HDO), but are limited by their quite poor HDO selectivity. Herein, a mesoporous Ni-Mo/SiO2-TiO2 catalyst was prepared by precipitation and impregnation method and used for methyl laurate HDO, yielding 96.3% n-dodecane yield at full methyl laurate conversion. Non-edible bio-lipids such as jatropha oil and waste cooking oil also converted to n-C14+16+18 hy-drocarbons with yields of 94.3% and 92.4%, respectively. Besides, Ni-Mo/SiO2TiO2 shows strong chemo-selectivity towards the HDO of ester groups. Experimental results showed that Mo-addition and Ti/Si molar ratio strongly influenced HDO selectivity. Oxygen vacancies formed on partial reduced TiO2 surface securely bond Ni NPs and activate C=O/C-O bonds, improving Ni NPs dispersion and promoting R-COOCH3 R-CHO reduction. Additional, Mo-addition switches reactant adsorption configuration from eta(1)(C)-acyl to eta(2)(C,O)-aldehyde, pro-moting the formation of R-CH2OH intermediate. Moreover, abundant Bronsted acidic sites (Mo4+-OH, Mo6+-OH, hydroxy groups) facilitate the HDO of R-CH2OH to R-CH3.