Amorphous Al₂O₃‐Supported NiMo Nanocatalysts: Boosting Type 2 Sites for Hydrodesulfurization Reaction

Abstract

Herein, we report superior Hydrodesulfurization (HDS) catalytic activity of ultrasmall NiMo supported on amorphous‐Al2O3 (A‐Al2O3) catalysts with enhanced type 2 sites. A‐Al2O3 was chosen as support because it has lower surface energy, better physicochemical properties, and enhanced acidic sites than the crystalline alumina phase. At 20% metal oxide composition, NiMo supported on A‐Al2O3 catalyst showed weak metal‐support interaction, higher sulfidation degree (80%) and higher amount of NiMoS sites (14.9 x 1019 sites/mg) with optimum stacking degree (2.5), leading to 1.4 and 1.2 times higher reaction rate constant and turn over frequency (TOF) respectively than wet impregnated NiMo supported on ℽ‐Al2O3 catalysts. Further, the Density Functional Theory (DFT) study supports the formation of a higher degree of type 2 sites (by confirming weaker active metal interaction for A‐Al2O3 surface than crystalline ℽ‐Al2O3), which leads to increased HDS catalytic activity.