Oxidation Desulfurization of Fuels by Using Amphiphilic Hierarchically Meso/Macroporous Phosphotungstic Acid/SiO2 Catalysts

A series of amphiphilic hierarchically meso/macroporous phosphotungstic acid (HPW)/SiO2 materials have been synthesized via a facile post treatment strategy and used as a catalyst for oxidative desulfurization (ODS). The SEM and TEM images revealed that as-prepared catalysts possessed a well-defined meso/macroporous structure and the average pore size of macropores and mesopores were estimated to be 210 and 2.79 nm, respectively. In addition, the existence of the ordered mesoporous structure was further confirmed by Small-angle XRD and N-2 adsorption-desorption. The wild-angle XRD and FT-IR spectra proved Keggin-type HPW incorporated into the silica matrix. The lipophilicity of catalysts was tested by the contact angle, which exhibited that the lipophilicity of catalysts had been improved increased with the usage of modifier. The dibenzothiophene removal of amphiphilic hierarchically porous HPW/SiO2 catalysts indicated that there was an optimum hydrophilic-ipophilic balance in ODS. The excellent performance in oxidative desulfurization can be ascribed to the advantages of the peculiar hierarchically meso/macroporous structure and the lipophilicity of catalyst which promoted the mass transport of aromatic sulfide in the pore channel and model fuel effectively. Moreover, the catalyst also exhibited excellent reusability with only slight performance decrease after regenerating for over 6 cycles. [GRAPHICS] .