Chemoselective hydrodeoxygenation of palmitic acid to diesel-like hydrocarbons over Ni/MoO2@Mo2CTx catalyst with extraordinary synergic effect

Chemoselective hydrodeoxygenation (HDO) of lipids to diesel-like hydrocarbons is important for biomass to biofuel conversion. Here we design a new Ni-based catalyst (Ni/MoO2@Mo2CTx) with extraordinary catalytic performance in the HDO of palmitic acid. To relieve the loss of C atom for Ni-based catalyst, partial oxidation of Mo2CTx MXene was used as a novel support. As a result, the catalytic activity and selectivity ratio of hexadecane/pentadecane (C-16/C-15) were enhanced over Ni/MoO2@Mo2CTx catalyst, and the major product of palmitic acid HDO is C-16, demonstrating a high C atom economy. This facilitated catalytic performance may be ascribed to the synergic effect of metal Ni, Mo2CTx MXene as well as MoO2 active sites. The palmitic acid (-COOH) can convert into hexadecanal (-CHO) and hexadecanol (-CH2OH) over Ni/MoO2@Mo2CTx catalyst in the initial stage. The metal Ni further contributes to the hydrogenation of the hexadecanal to C-15 with the cleavage of C-C bonds by decarbonylation (DCO) route. MoO2 nanoparticles obtained from Mo2CTx oxidation accelerate the scission of C-O bonds of the hexadecanol to improve the selectivity of C-16 by hydrogenation-dehydration route.