Effective Combination of the Metal Centers in MOF-Based Materials toward Sustainable Oxidation Catalysts.

A successful encapsulation of Keggin-type polyoxomolybdate (H 3 [PMo 12 O 40 ], PMo 12 ) into metal-organic framework (MOF) materials with an identical framework but distinct metal centers (ZIF-8 with Zn 2+ and ZIF-67 with Co 2+ ) was accomplished by a straightforward room-temperature procedure. The presence of Zn 2+ in the composite material PMo 12 @ZIF-8 instead of Co 2+ in PMo 12 @ZIF-67 caused a remarkable increase in the catalytic activity that achieved a total oxidative desulfurization of a multicomponent model diesel under moderate and friendly conditions (oxidant: H 2 O 2 and solvent: ionic liquid, IL). Interestingly, the parent ZIF-8-based composite with the Keggin-type polyoxotungstate (H 3 [PW 12 O 40 ], PW 12 ), PW 12 @ZIF-8, did not show the relevant catalytic activity. The ZIF-type supports present an appropriate framework to accommodate active polyoxometalates (POMs) into their cavities without leaching, but the nature of the metallic center from the POM and the metal present in the ZIF framework were vital for the catalytic performance of the composite materials.