The effect of the Mo/W ratio on the catalytic properties of alumina supported hydrotreating catalysts prepared from mixed SiMo6W6 and SiMo9W3 heteropolyacids

New mixed H4[SiMonWn-12O40] (n = 6 and 9) Keggin type heteropolyacids (HPAs) have been successfully synthesized, as confirmed by single-crystal XRD, Raman IR spectroscopy analysis. The resulting polyoxometallates were used for preparation of hydrotreatment catalysts. Mo(W)/Al2O3 catalysts synthesized incipient wetness impregnation alumina support with water solutions prepared HPAs corresponding counterparts based on mixture monometallic H4[SiMo12O40] H4[SiW12O40] HPAs. Oxidic analyzed to determine the precursor structure after deposition. Catalysts in sulfided state characterized high-resolution transmission electron microscopy (HRTEM), high angle annular dark field imaging (HAADF) X-ray photoelectron (XPS) tested co-hydrotreating dibenzothiophene (DBT) naphthalene. use new made it possible obtain MoWS2 active centers, which was HAADF. Moreover, Mo/(Mo + W) ratio has a direct effect phase species. An ordered core-shell Mo atoms core is maintained until fraction molybdenum MoW/Al2O3 catalyst exceeds 50 %, where more disordered observed. this 0.5 optimal achieve maximum catalytic activity. Indeed, turnover frequencies (TOF) edge centers random distribution cluster Mo9W3/Al2O3, lower compared that Mo6W6/Al2O3 structure.