Metastable structures and isotope exchange reactions in polyoxometalate ions provide a molecular view of oxide dissolution.
Reactions involving minerals and glasses in water are slow and difficult to probe spectroscopically but are fundamental to the performance of oxide materials in green technologies such as automotive thermoelectric power generation, CO2 capture and storage and water-oxidation catalysis; these must be made from geochemically common elements and operate in hydrous environments. Polyoxometalate ions (POMs) have structures similar to condensed oxide phases and can be used as molecular models of the oxide/water interface. Oxygen atoms in POM exchange isotopes at different rates, but, at present, there is no basis for predicting how the coordination environment and metal substitution influences rates and mechanisms. Here we identify low-energy metastable configurations that form from the breaking of weak bonds between metals and underlying highly coordinated oxygen atoms, followed by facile hydroxide, hydronium or water addition. The mediation of oxygen exchange by these stuffed structures suggests a new view of the relationship between structure and reactivity at the oxide/solution interface.
Corning Inc., One Science Center Drive, SP TD 01-1, Corning, New York 14831, USA. rustadjr@corning.com
James R
JR
Rustad
William H
WH
Casey
D007477:Ions / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
D007477:Ions; D010087:Oxides; D010100:Oxygen; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates