Highly active phosphotungstic acid immobilized on amino functionalized MCM-41 for the oxidesulfurization of dibenzothiophene

Phosphotungstic acid H3PW12O40 (HPW) was successfully immobilized on the surface of MCM-41 functionalized with amino groups. The obtained catalysts were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectra, thermo-gravimetric analysis, and inductively coupled plasma atomic emission spectroscopy. The results indicated that the surface area of MCM-41 support decreased after it was functionalized with amino groups, whereas the HPW active species retained its Keggin structure. HPW–NH2–MCM-41 exhibited excellent catalytic performance for oxidesulfurization (ODS) of dibenzothiophene (DBT). Under optimal conditions, the conversion of DBT reached up to 100%. The catalyst could be recycled five times without significant loss of catalytic activity. The excellent recyclability was attributed to the strong interaction between the amino groups and the HPW species.