An integrated giant polyoxometalate complex for photothermally enhanced catalytic oxidation.

Abstract

A strategy integrating near infrared (NIR) photothermal and catalytic effects within one active center beyond ultraviolet and visible light is proposed without the combination of separated photothermal transformation components. A giant polyoxomolybdate, which has high NIR photothermal conversion efficiency, is selected as the model catalyst, while a cationic β-cyclodextrin is used to cover its negatively charged surface electrostatically. Under NIR light radiation, the designed catalyst increases catalytic activity of cyclohexene oxidation under O2 atmosphere in water. The conversion reaches about pentaploid of the reaction without NIR radiation. By excluding heating effect from the external heater at the same temperature, about twice as much enhancement, which can be attributed to the sole photothermal action, is still observed. While the catalytic center is shielded by the organic porous layer, the surface cavity allows the integrated catalyst to conduct a selective catalysis by screening the molecules in size over the surface channel.