Theoretical Insight into the Performance of MnII/III-Monosubstituted Heteropolytungstates as Water Oxidation Catalysts.
Inorg Chem
; 58(23): 15751-15757, 2019 Dec 02.
Article
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| MEDLINE
| ID: mdl-31710211
ABSTRACT
The performance of MnII/III-monosubstituted heteropolytungstates [MnIII(H2O)GeW11O39]5- ([GT-MnIII-OH2]5-, where GT = GeW11O39) and [MnII(H2O)GeW11O39]6- ([GT-MnII-OH2]6-) as water oxidation catalysts at pH 9 was explored using density functional theory calculations. The counterion effect was fully considered, in which five and six Na+ ions were included in the calculations for water oxidation catalyzed by [GT-MnIII-OH2]5- and [GT-MnII-OH2]6-, respectively. The process of water oxidation catalysis was divided into three elemental stages (i) oxidative activation, (ii) O-O bond formation, and (iii) O2 evolution. In the oxidative activation stage, two electrons and two protons are removed from [Na5-GT-MnIII-OH2] and three electrons and two protons are removed from [Na6-GT-MnII-OH2]. Therefore, the MnIV-O⢠species [Na5-GT-MnIV-Oâ¢] is obtained. Two mechanisms, (i) water nucleophilic attack and (ii) oxo-oxo coupling, were demonstrated to be competitive in O-O bond formation triggered from [Na5-GT-MnIV-Oâ¢]. In the last stage, the O2 molecule could be readily evolved from the peroxo or dinuclear species and the catalyst returns to the ground state after the coordination of a water molecule(s).
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01-internacional
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MEDLINE
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En
Revista:
Inorg Chem
Año:
2019
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Article