Tetrahedral Keggin Core Tunes the Visible Light-Assisted Catalase-Like Activity of Icosahedral Keplerate Shell.
Inorg Chem
; 61(20): 7878-7889, 2022 May 23.
Article
em En
| MEDLINE
| ID: mdl-35533083
ABSTRACT
In this work, the effect of Keggin polyoxometalates encapsulated in Keplerate {Mo72Fe30} shell (K shell) on the visible light-assisted catalase-like activity (H2O2 dismutation) of the resulting core-shell clusters PMo12@K, SiMo12@K, and BW12@K was investigated. Superior photodismutation activity of PMo12@K compared to that of K shell and two other core-shell clusters was discovered. The homogeneity of PMo12@K and its improved oxidative stability, increased redox potential, and reduced band gap caused by a synergistic effect between the Keplerate shell and Keggin core seem reasonable to explain such a superiority. The light-dependent photocatalytic performance of PMo12@K evaluated by action spectra revealed a maximum apparent quantum efficiency (AQY) at 400 nm, demonstrating the visible light-driven photocatalytic reaction. A first-order rate constant of 2 × 10-4 s-1 and activation energy of 108.8 kJ mol-1 alongside a turnover frequency of 0.036 s-1 and a total turnover number of up to â¼3800 approved the effective photocatalytic activity and improved the oxidative stability of PMo12@K. A nonradical photocatalytic mechanism through a Fe-OOH intermediate was proposed. Thus, the structure, optical activity, and oxidative stability of a host Keplerate-type nanocluster can be tuned significantly by encapsulation of a guest, like "cluster-in-cluster" structures, which opens the scope for introducing new visible light-sensitive hierarchical nanostructures.
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01-internacional
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MEDLINE
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En
Ano de publicação:
2022
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Article