Rational design of a catalyst of high efficiency and stability for solar energy conversion represents a major challenge. Molecular catalysts can not only act as ideal structural models for detailed mechanism study on the molecular level, but also generate valuable molecular insight for further improvement of catalysts with both efficiency and robustness via bottom-up synthetic techniques.Here, we present our study by reviewing a water-soluble molecular K7[CoIIICoII(H2O)W11O39] catalyst developed recently for solar energy conversion. This catalyst is the first Keggin polyoxoxmetalate of high efficiency and stability used for the water splitting via both visible-light driven and thermal water oxidation. Our study demonstrates that the oxygen yield and turnover numbers (TON) can reach as high as 60% and 15, respectively, under the thermal water oxidation conditions. More importantly, the initial turnover frequency (TOF), turnover numbers (TON), and quantum yield can reach 0.5 s-1, 360, and 27%, respectively, in borate buffer (pH = 9.0) under the investigated photocatalytic conditions. Multiple experiments including laser flash photolysis and DLS test ruled out the possibility that neither free Co2+ions were present in the reaction solution norcobalt oxide/hydroxide nanoparticles in situ formed from the assumed decomposition of the title compound and arecollectively in support of its true molecular nature.Our study presents that the unique structural and electronic features of the studied molecular catalyst play the essential role in maintaining both catalytic stability and efficiency for water splitting.

Molecular water splitting catalyst of high efficiency and robustness

246th National Meeting (2013)

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