Host-guest synthesis and encapsulation of phosphotungstic acid in MIL-101 via 'bottle around ship': An effective catalyst for oxidative desulfurization

摘要

Successful encapsulation of phosphotungstic acid (PTA) within the nanocages of MIL-101 has been achieved via "bottle around ship" approach under static condition. XRD, FT-IR, ~(31)P MAS NMR, N2 adsorption, SEM-EDS and XRF confirm the incorporation and well-distribution of PTA in both middle and large cavities of the MIL-101. SEM, XRD and TEM reveal the dominant crystal shapes of high loading PTA@MIL-101 are a monolithic and the adjacent lattice planes of MIL-101 are larger due to the addition of PTA. The host-guest composite materials PTA@MIL-101 containing 17-50wt.% of PTA have been obtained and demonstrate an excellent catalytic performance in the oxidative desulfurization process of the refractory sulfur-containing compounds. This is the first example of the application of MIL-101 or PTA@MIL-101 composite materials in oxidative desulfurization. The reactivity of the sulfur-containing compounds follows the order DBT > 4,6-DMDBT > BT. In four consecutive reaction cycles, the catalyst recovery is in excess of 71%, while the DBT conversion slightly decreases.