Polyoxometalates(POMs),with their attractive topological and electronic properties,have been demonstrated over the last few decades to be efficient catalysts for many reactions.In a new direction,POMs having a purely inorganic framework are now being explored as efficient catalysts for water oxidation.This review focuses on very recent developments of POM-based catalysts for water oxidation to O2.In the very extensive family of POMs,tetra-core sandwich-type Ru-and Co-containing POM complexes,namely [Ru4O4(OH)2(H2O)4(γ-SiW10O36)2]10-and [Co4(H2O)2(γ-PW9O34)2]10? exhibit the ability to facilitate water oxidation under electrocatalytic and/or photocatalytic conditions.However,it is concluded that much work still needs to be done to explain the catalytic mechanisms and optimize these catalytic systems.In addition,recent trends in using ionic liquids as media to modify the electrolytic environment and enhance water oxidation are highlighted. Polyoxometalates (POMs), with their attractive topological and electronic properties, have been demonstrated over the last few decades to be efficient catalysts for many reactions. A new direction, POMs having a purely inorganic framework are now being explored as efficient catalysts for water oxidation . This review focuses on very recent developments of POM-based catalysts for water oxidation to O2.In the very extensive family of POMs, tetra-core sandwich-type Ru-and Co-containing POM complexes, namely [Ru4O4 (OH) 2 H2O) 4 (γ-SiW10O36) 2] 10-and [Co4 (H2O) 2 (γ-PW9O34) 2] 10? Exhibit the ability to facilitate water oxidation under electrocatalytic and / or photocatalytic conditions. work still needs to be done to explain the catalytic mechanisms and optimize these catalytic systems.In addition, recent trends in using ionic liquids as media to modify the electrolytic environment and enhance water oxidation are highlighted.