Hexagonal mesoporous silicas with and without Zr as supports for HDS catalysts

Hexagonal mesoporous materials (HMS) with and without zirconium were used as supports for preparation of HDS catalysts. The catalysts prepared by modification of the supports with 12-phosphomolybdic acid (HPMo) were characterised by nitrogen adsorption, IR spectroscopy, TPD of ammonia, TPR and catalytic activity in thiophene hydrodesulphurisation. Parent silicas showed mesoporous structure with BET surface area between 1200 and 800 m² g⁻¹, pore size diameter around 3.3 nm and acidity around 0.3 mmol NH₃ g⁻¹. Molybdenum catalysts possess stronger acidity than the supports used. The catalytic activities in hydrodesulphurisation of thiophene of the molybdenum containing catalysts prepared with HMS were higher than the activity of the catalyst prepared with amorphous silica. Higher acidity of Zr–HMS supports lead to lower stability in the thiophene conversion.