Solvent-free hydrodeoxygenation of bio-lipids into renewable alkanes over NiW bimetallic catalyst under mild conditions

Solvent-free hydrodeoxygenation (HDO) of bio-lipids into renewable alkanes by non-precious Ni metal catalysts usually required harsh reaction conditions of, for example, over 360 degrees C. Herein, we reported a NiW bimetallic catalyst that reached a 100 % HDO efficiency over oleic acid under a mild condition of 320 degrees C. This was due to a catalytic synergy of Ni and oxygen vacancy (OV) site over the rate-determined step, C-36 ester hydrogenolysis, in HDO. The OV site created by a partially H-2 reduction of WO3 was confirmed by XPS and UV-vis characterizations. Primary density functional theory calculation demonstrated that OV had stronger adsorption over carbonyl oxygen atom in carboxyl group compared to Ni site. In this way, the activation and cleavage of C-alkoxy-O bond during C-36 ester hydrogenolysis under mild conditions were realized. This developed NiW bimetallic catalyst highlighted a great promise for the solvent-free HDO of bio-lipids into renewable alkanes under mild conditions.