Synthesis of β-Mo 2N 0.78 hydrodesulfurization catalyst in mixtures of nitrogen and hydrogen

Abstract

β-Mo 2N 0.78 catalyst was synthesized via the temperature-programmed reaction between N 2–H 2 mixture gases and molybdenum oxide. The influences of the synthesis conditions on catalyst structure and catalyst hydrodesulfurization (HDS) behavior were also studied. H 2-TPR experiment was used to investigate the structure changes of catalyst before and after HDS reaction. Preparation results showed that β-Mo 2N 0.78 can be formed at a final nitriding temperature of 923–1023 K and N 2/H 2 ratios of 1/4–1/1. The formation of MoO 2 intermediate results in the low surface area β-Mo 2N 0.78 product. The thiophene HDS result indicated that β-Mo 2N 0.78 also has HDS catalytic activity. Its bulk structure is retained after HDS reaction although sulfur replaces the surface oxygen as determined by TPR examination. Pre-reduction does not improve the HDS activity of passivated β-Mo 2N 0.78 although hydrogen reduction can remove the oxygen from surfaces. The catalytic activity of passivated nitride decreases with the increasing of final nitriding temperature from 923 to 1123 K, and there is a suitable N 2–H 2 ratio to prepare high activity β-Mo 2N 0.78 catalyst.