Synthesis of defected UIO-66 with boosting the catalytic performance via rapid crystallization

Due to environmental and health concerns, it is very important to develop high activity oxidative desulfurization (ODS) catalyst for petroleum purification. Recently, defect engineering of metal organic frameworks (MOFs) to generate a large number of unsaturated catalytic active sites is a very promising approach. Defective MOF has good research value as ODS catalyst. Here, UIO-66 with lots of defects can be prepared by rapid crystallization using concentrated hydrochloric acid as a modulator. The prepared UIO-66 material has good industrial applicability due to its low synthesis temperature (100 degrees C), short synthesis time (20-30 min), large-scale preparation, and excellent catalytic performance (dibenzothiophene can be entirely removed in 6 min under the optimal catalytic conditions [25-mg catalyst, 60 degrees C, O/S 7.5]). The obtained material exhibits not only extraordinary ODS activity of 37.6 mmol h(-1) g(-1) but also good cycle stability for the removal of DBT (in 7 cycles without significant loss of activity, greater than 90.2%). And for large space volume 4,6-DMDBT, it also shows excellent catalytic performance. The ODS mechanism of defect UIO-66 for DBT is explored, and it proves that hydroxyl radicals and superoxide radicals are generated and play a critical role in ODS reaction. The excellent catalytic performance of defect UIO-66 gives mainly the credit to the abundant defect sites, large specific surface area, and pore volume.

Automated summary

Developing high activity oxidative desulfurization (ODS) catalyst is crucial for petroleum purification, and defect engineering of metal organic frameworks (MOFs) offers a promising approach to achieve this goal. The preparation of defect-rich UIO-66 material with excellent catalytic performance demonstrates the importance of abundant defect sites, large specific surface area, and pore volume in ODS reactions.