Chemical-switching strategy for the production of green biofuel on NiCo/MCM-41 catalysts by tuning atmosphere.

• The surface properties of NiCo/MCM-41 can be effectively tuned by pretreatment gas. • The largest amount of Lewis acid on NiCo/MCM-41-H promoted the HDO pathway. • NiCo/MCM-41-H can effectively convert jatropha oil into green biofuel. NiCo bimetallic catalyst was one of potential candidates used toward the hydrodeoxygenation of vegetable oils. However, there is still lack for digging out the relationship between micro-structure pretreated by various atmosphere and its catalytic performance. To hunting the relationship, NiCo/MCM-41 precursor was synthesized via the conventional co-impregnation method, and further pretreated by different atmospheres, including NH 3 , CH 4 /H 2 and H 2 in order to tune the particle size, active component dispersion, and acid properties of the catalysts. NiCo/MCM-41-H pretreated by H 2 exhibits superior catalytic performance (65.8 wt% biofuel yield and 98.2% C 12 -C 18 alkanes selectivity) on converting jatropha oil than that by NH 3 and by CH 4 /H 2. For comparison, the NiCo/MCM-41-H shows the smallest NiCo alloy grains, the smallest amount of strong acid, the lowest Brønsted acid/Lewis acid ratio, and the most uniform dispersion of Ni and Co. All the distinct surface properties of NiCo/MCM-41-H reasonably account for high efficiency in hydrodeoxygenation of jatropha oil. The work reveals the relationship between NiCo bimetallic catalyst structure and its hydrodeoxygenation performance, and provides a robust pretreatment method for tuning the surface properties to improve its catalytic performance for converting biomass oils into green biofuel. [ABSTRACT FROM AUTHOR]