Sb-V-Ox catalysts—Role of chemical composition of MCM-41 supports in physicochemical properties

SbVOx binary oxides were loaded on MCM-41 matrices of various chemical compositions: silicate (MCM-41), Nb-silicate (NbMCM-41), and Al-silicate (AlMCM-41). Vanadium and antimony were introduced by the post synthesis wetness impregnation carried out step by step (first V next Sb). The materials were characterised by N2 adsorption/desorption, XRD, UV–vis, ESR, H2-TPR, FT-IR combined with pyridine adsorption, and test reaction–hydrosulphurisation of methanol. SbVOx dispersion was much higher when the support contained transition metal (NbMCM-41). Tetrahedrally coordinated vanadium(IV) species were deduced on all prepared samples from UV–vis spectra and were the only registered species on SbV/NbMCM-41 and SbV/AlMCM-41, whereas octahedrally ones were also present on SbV/MCM-41 and SbV/SiO2. In bulk SbVOx octahedral coordination dominated. The chemical composition of mesoporous support determined acidic–basic properties of SbVOx catalysts and influenced the activity and selectivity in methanol hydrosulphurisation. The presence of Lewis acid–base pairs in the SbV/AlMCM-41 and SbV/NbMCM-41 catalysts strongly activated thiol formation in the reaction between methanol and hydrogen sulphide, whereas bulk binary oxides and SbVOx loaded on silicate MCM-41 were less active and exhibited different selectivity.