Co-MOF nanocatalysts of tunable shape and size for selective aerobic oxidation of toluene

Abstract

A series of Co-MOF nanocrystals are prepared in a water/DMF/TX-100/ionic liquid quaternary W/O microemulsion system at room temperature. DMF is chosen as the additive to improve the dissolution of organic linkers in water droplets, which ensures Co-MOF crystal formation in the polar cores. The shape and size of these crystals are effectively controlled by tuning the ionic liquid cation alkyl chain length and the ratio of water to TX-100 and have obvious differences compared to those prepared by the traditional solvothermal method. Molecular dynamic simulations prove the mechanism of the crystal growth process in this microemulsion system. The toluene selective oxidation reaction is selected as the model reaction to study the catalytic performance of these materials. Among all these catalysts, the multilayer nanoplate Co-MOF shows the best catalytic activity and selectivity for toluene owing to the small crystal size and exposed special crystal surfaces of this material. Our synthesis strategy provides a facile way to develop MOF nanocatalysts with controllable shapes and sizes for catalytic oxidation reactions.