Homogeneous electrocatalytic water oxidation at neutral pH by a robust trinuclear copper(ii)-substituted polyoxometalate.

[(α-SbW9O33)2Cu3(H2O)3]12- (1) was tested as the first copper-containing polyoxometalate catalyst for O2 production via electrocatalytic water oxidation at a neutral pH. Multiple lines of experimental evidence confirm that catalytic water oxidation by 1 takes place in the absence of any heterogeneous species generated in situ. The catalytic capabilities of 1 and equal amounts of CuCl2 are completely different for electrocatalytic water oxidation behavior.