Preparation of the CuWO₄/SBA-15 catalyst and its performance in the photocatalytic oxidation desulfurization

The CuWO₄/SBA-15 catalyst was prepared with CuWO₄ as the active composite and mesoporous SBA-15 molecular sieve as the support and characterized by XRD, N₂ adsorption and desorption, FT-IR, UV-vis, SEM, EDS and TEM; the performance of CuWO₄/SBA-15 catalyst in the photocatalytic oxidation desulfurization (PODS) was investigated by using the dodecane solution of dibenzothiophene (DBT) as the model fuel. The results show that the CuWO₄/SBA-15 catalyst can maintain the two-dimensional hexagonal mesoporous structure of the support and the active component is evenly distributed on the support; the surface area, pore size and pore volume of the CuWO₄/SBA-15 catalyst decrease with an increase in the amount of active component. Compared with CuWO₄, the CuWO₄/SBA-15 catalyst displays a blue shift in absorption boundary of UV-vis spectra and an increase of the band gap. With a CuWO₄/SiO₂ mass ratio of 0.07, catalyst mass percentage of 3% in the model fuel, O/S molar ratio of 10:1, and extractant/oil volume ratio of 1:1, the desulfurization rate reaches 81.5% by carrying out the PODS reaction under light for 100 min, which is obviously higher than that over CuWO₄; moreover, no obvious decrease of catalytic activity for CuWO₄/SBA-15 was observed after 6 runs of PODS. It is proposed that ·OH and h⁺ are the main reactive intermediates in PODS.