Highly efficient Ni/Beta catalyst for one-step hydrodeoxygenation-isomerization of fatty acid ester to bio-jet fuel

The catalytic performance of bifunctional catalyst for one-step hydrodeoxygenation of fatty acid esters to bio-jet fuel is contingent upon the features of metal component and acid support. However, it remains challenging to simultaneously modulate these structural features with the impregnation method. Herein, the metal particle size, pore structures and acidity of Ni/Beta catalysts are regulated simultaneously during the citric acid-assisted impregnation process. The particle size of Ni over the Ni/Beta catalyst is greatly decreased due to the steric and coordination effect of citric acid on metal. The electron density of the small Ni particle is reduced by the enhanced electron transfer between Ni and Beta. Besides, the dealumination effect of citric acid on Beta zeolite reduces strong Brønsted acid sites and introduces 0.85 times more mesopores into the Ni/Beta catalyst, compared with the counterpart obtained by conventional impregnation method. The enhanced metal dispersion over the Ni/Beta catalyst promote hydrodeoxygenation of reactants and favor hydrodecarbonylation reaction path. The reduced Brønsted acid sites and abundant mesopores inhibit cracking of intermediate and products. The space–time yield of C 12 and C 11 reaches 33.4 mmol·g −1 ·h −1 in hydrodeoxygenation of methyl laurate which is the highest value reported.