MOF-808(Zr)-supported with Keggin Polyoxometalates as an efficient oxidative desulfurization catalyst

The design and fabrication of polyoxometalates-based metal-organic frameworks (POM@MOF) represent an emerging technology developed to tackle environmental problems. Zirconium metal-organic frameworks such as MOF-808 have catalytic activity for the oxidative desulfurization of dibenzothiophene (DBT). However, MOF-808 (Zr) is not suitable for optimum recycling and requires additional catalytic active sites for the complete oxidation of DBT. The incorporation of POMs within MOF-808 to yield POM@MOF-808 warrant an effective strategy to increase the accessible active sites of the composites and endow them with additional stability. Herein this work, we describe the preparation of novel PW12@MOF-808 and PW11@MOF-808 composites by a simple encapsulation method under compatible reaction conditions. The prepared catalysts were analyzed by various techniques and have indicated successful formation. The loading of the POMs significantly reduced the surface area and total pore volume of the parent MOF-808 suggesting the uniform dispersion of the support materials within the frameworks. PW11@MOF-808 demonstrated excellent catalytic activity by removing 99.32% of DBT within 30 min and was better than 85.86% for MOF-808 under the same reaction condition. The remarkable efficiency demonstrated by the catalyst is attributed to the increasingly accessible active sites that boosted the reaction conversion of DBT. The catalyst showed recyclability seven times without obvious loss in activity. The application of PW11@MOF-808 may provide an impetus to the practical exploitation of the produced nanocomposites.