Catalytic Water Oxidation Based On Ag(Ⅰ)-substituted Keggin Polyoxotungstophosphate

On the basis of master’s thesis of Yanyi Yang,the paper has studied the dynamics of [H₃Ag^I（H₂O）PW₁₁O₃₉]^3- catalyzed S₂O₈^2- oxidation of water deeply. When K₃[H₃AgIPW₁₁O₃₉]·12H₂O is dissolved in the solutions, the [H₃Ag^I（H₂O）PW₁₁O₃₉]^3- anions are formed. The rate of the water oxidation reaction is a first-order law with respect to the concentrations of [H₃Ag^I（H₂O）PW₁₁O₃₉]^3- and S₂O₈^2-, respectively, and the TON value of the catalyst is 95.0 in 94 h. What do we learn through 18 O isotope detection that produced O₂ is all form water molecules. The intermediate species in water oxidation reaction are [H₃AgII（H₂O）PW₁₁O₃₉]^2- and a small amount of [H₃Ag^IIIOPW₁₁O₃₉]^3-, which is determined by 31 P NMR, Raman spectra and UV-Visible spectra. The reaction mechanism has been proposed, in which it is deduced that the generation of H₂O₂ may be a rate-determining step.Using Keggin-Heteropolytungstates anions [PW₁₀V₂O₄₀]^5- as building units, three rare earth polyoxometalate complexes havwe been prepared under hydrothermal condition. They are composed of Keggin type polyoxometalate anion [PW₁₀V₂O₄₀]^5-, 3D Ln³⁺-pdc^2--H₂ O cationic framework with a three-dimensional pore structure.In addition, a quaternary ammonium salt of [H₃Ag^IPW₁₁O₃₉]^3- has been synthesized. It is preliminary characterized by IR. The redox performance has been studied in the acetonitrile solvent.