Highly Dispersed Polyoxometalate-Doped Porous Co3O4 Water Oxidation Photocatalysts Derived from POM@MOF Crystalline Materials

Rational design of earth-abundant photocatalysts is an important issue for solar energy conversion and storage. Polyoxometalate (POM)@Co3O4 composites doped with highly dispersive molecular metal-oxo clusters, synthesized by loading a single Keggin-type POM cluster into each confined space of a metal-organic framework (MOF), exhibit significantly improved photocatalytic activity in water oxidation compared to the pure MOF-derived nanostructure. The systematic synthesis of these composite nanocrystals allows the conditions to be tuned, and their respective water oxidation catalytic performance can be efficiently adjusted by varying the thermal treatment temperature and the feeding amount of the POM. This work not only provides a modular and tunable synthetic strategy for preparing molecular cluster@TM oxide (TM = transition metal) nanostructures, but also showcases a universal strategy that is applicable to design and construct multifunctional nanoporous metal oxide composite materials.