Electronic binding of sulfur sites into Al₂O₃-ZrO₂ supports for NiMoS configuration and their application for Hydrodesulfurization

We present an effective chemical synthesis of bimetallic Nickel-Molybdenum catalysts. The catalysts were made using a sol-gel method with alumina modified by zirconia (Al₂O₃-xZrO₂₎ support with x = 0, 10 and 15 wt-% respectively. In order to measure their catalytic activity, they were evaluated through hydrodesulfurization (HDS) reaction using industrial gas oil 2 wt-% sulfur content. Results, indicate an important increase of their catalytic activity in presence of zirconia, probably as caused by electron donation from atoms as presented in zirconia tetragonal structure (XRD). Furthermore, using high resolution characterization techniques such as X-ray Photoelectron Spectroscopy (XPS) and Temperature Programmed Reduction of Sulfides (TPR-S) has revealed a special interaction between zirconia and active sites, confirming the electron donation, mainly at Mo octahedral sites, as occurred due to formation of so-called NiMoS phase. In order to complete our analysis, images of High-Resolution Transmission Electron Microscopy (HRTEM) shown dispersed laminar molybdenum sulfide structures with some bending, high stacking over c-axis when the sol-gel alumina was modified by zirconium domains.