Tetrahedral Keggin Core Tunes the Visible Light-Assisted Catalase-Like Activity of Icosahedral Keplerate Shell br

In this work, the effect of Keggin polyoxometalatesencapsulated in Keplerate {Mo72Fe30} shell (K shell) on the visiblelight-assisted catalase-like activity (H2O2dismutation) of theresulting 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 clusterswas discovered. The homogeneity of PMo12@K and its improvedoxidative stability, increased redox potential, and reduced band gapcaused by a synergistic effect between the Keplerate shell andKeggin core seem reasonable to explain such a superiority. Thelight-dependent photocatalytic performance of PMo12@K eval-uated by action spectra revealed a maximum apparent quantumefficiency (AQY) at 400 nm, demonstrating the visible light-driven photocatalytic reaction. Afirst-order rate constant of 2x10-4s-1and activation energy of 108.8 kJ mol-1alongside a turnover frequency of 0.036 s-1and a total turnover number of up to similar to 3800approved the effective photocatalytic activity and improved the oxidative stability of PMo12@K. A nonradical photocatalyticmechanism through a Fe-OOH intermediate was proposed. Thus, the structure, optical activity, and oxidative stability of a hostKeplerate-type nanocluster can be tuned significantly by encapsulation of a guest, like"cluster-in-cluster"structures, which opens thescope for introducing new visible light-sensitive hierarchical nanostructures.