Journal of Catalysis, Vol.201, No.1, 22-36, 2001
Ultrasonically controlled deposition-precipitation - Co-MoHDS catalysts deposited on wide-pore MCM material
Mo and Co oxides were precipitated under ultrasonication treatment from Mo(CO)(6) and Co(CO)(3)NO dissolved in decalin. Introduction of wide-pore Al-MCM-41 material with an average pore diameter 8.3 nm and a surface area of 840 m(2)/g increased the Mo oxide precipitation rate by an order of magnitude. This is a result of an ultrasonically induced chemical interaction between metal carbonyl (oxide) and the surface silica atomic layer yielding surface silicates (XPS, MAS NMR). It was demonstrated for the first time that ultrasonication of such a slurry yields deposition-precipitation of the corresponding metal oxide, forming a close-packed monolayer at the support's surface (Nz adsorption, HR-TEM, XPS, XRD). Ultrasonically controlled deposition-precipitation produced similar to 45 wt% MoO3 loading, which is saturation of the wide-pore Al-MCM-41 surface monolayer. The high-loading Go-MolAl-MCM-41 catalyst prepared by ultrasonically controlled deposition-precipitation was 1.7 times more active in HDS of dibenzothiophene, based on the reaction rate normalized per catalyst weight, than commercial Go-Mo-Al catalyst.
Keywords:catalyst preparation by ultrasonication;deposition-precipitation;Co-Mo on MCM-41;Mo oxide monolayer;HDS