Abstract: An unprecedented role for metal-oxide cluster-anions (polyoxometalates, or POMs) as covalently coordinated inorganic ligands for individual anatase nanocrystals and hematite nanocrystals, gives isolable anionic clusters uniquely positioned between molecular macroanions and traditional colloidal nanoparticles.^[1],[2] POM anion K₈Nb₆O₁₉ serves as tridentate “capping” ligand for complexed Cu(II) ions linked to CuO (tenorite) cores. Different spectroscopic methods, electron microscopic images, and analytical measurements confirm the presence of POM-capping ligand, covalently bound to the surfaces of the 3-6 nm tenorite cores. On illumination with a visible light, the hybrid NCs oxidized water in presence of S₂O₈^2- as a sacrificial oxidant (Figure 1). Indefinite stability of these unique complexes in water over a wide range of pH values, including the isoelectric point of tenorite, led us to study the photochemical water oxidation in different pH values. Kinetic study; dependence of photochemical O₂ production rate with respect to the concentration of [NCs] and [S₂O₈^2-] is in progress to understand the mechanism of water oxidation.

Figure 1. Visible-light-driven water oxidation by the water-soluble complex of tenorite.

References:

1. M. Raula, G. Gan Or, M. Saganovich, O. Zeiri, Y. Wang, M. R. Chierotti, R. Gobetto, I. A. Weinstock, Angew. Chem. Int. Ed. 2015, 54, 12416-12421.
2. Biswarup Chakraborty, Gal Gan-Or, Manoj Raula, Eyal Gadot & I. A. Weinstock, Nature Communications, 9, 2018, 4896