“…, W 6+ , Mo 6+ , V 5+ , Ta 5+ ) and oxygen atoms of metal–oxygen cluster (MO x ) polyhedrons, 15–17 have developed into molecular nanoclusters with a uniform structure and well-defined composition exhibiting a wide range of applications in catalysis, nanoscience, biology, medicine and other fields. 18,19 POMs can be deemed as analogues of semiconductor metal oxides because they are all composed of d0 transition metals and have similar electronic properties, containing a specific gap of HOMO–LUMO. 20–23 POMs have tunable composition, structure, charge and size as well as distinct photoinduced charge transfer properties, strong photooxidation–photoreduction capability, and elevated chemical and thermal stability, which are essential in photocatalysis.…”