Pyridine adsorption for probing electron-acceptor sites on the surface of titanium oxide with supported silver, copper, and gold ions

The results of investigation of the adsorption kinetics of pyridine (Py) show that the M+z = Ag+, Cu+2, and Au+3 ions supported on the surface of TiO2 (anatase) significantly increase its electron-acceptor properties. Two types of M+z/TiO2 adsorption sites are characterized by the various numbers of the pyridine coordination centers M and their oxidation states. Linear correlations between the rate constants of pyridine adsorption and the ionic radii are observed in the cases of both types of sites. The adsorption stoichiometry of the less active sites is Py-2M, where M = Cu+, Au+, and Ag0. The linear dependence of the antibacterial activity of M+z/TiO2 on the ionic charge z = +1 (for Ag), +2 (for Cu), and +3 (for Au), as well as the ability of bacteria to reduce dissolved silver and gold ions and those supported on TiO2 to colloidal metals, is also found. © 2015, Pleiades Publishing, Ltd.