Synthesis of novel Mo-Ni@Al2O3 catalyst for converting fatty acid esters into diesel-range alkanes with enhanced hydrodeoxygenation selectivity

Abstract

Al2O3-supported Ni-Mo as a low-cost and efficient bimetallic catalyst has been applied in the hydrodeoxygenation of plant oils or fats for production of high-quality hydrocarbon fuels, but it is still challenge to avoid the serious cleavage of C-C bonds caused by isolated single-metal Ni sites. Herein, we report a novel Al2O3-supported Mo-Ni catalyst (Mo-Ni@Al2O3) with Ni and Mo sites in close proximity to enhance the hydrodeoxygenation (HDO) selectivity of fatty acid esters. Compared with the conventional Mo-Ni/γ-Al2O3 catalyst showing high hydrogenolysis activity for C−C bonds, the Mo-Ni@Al2O3 catalyst exhibited higher HDO selectivity towards the diesel-range alkanes. Detailed characterizations reveal that during the synthesis of Mo-Ni@Al2O3 catalyst, the loaded Ni species were present in two forms after reduction in a H2 flow, one is the closely contact of Ni and Mo bimetallic sites and the other is NiAl2O4, which enhances the synergistic promoting effect between Ni and Mo sites and inhibits the presence of isolated metallic Ni active sites, thereby exhibiting the enhanced remarkably HDO selectivity towards target products.