Sonoelectrochemical methods of preparing silver-coated TiO₂ nanoparticles with extremely high coverage

In this study, we report the first sonoelectrochemical methods of preparing elemental Ag(0)-coated TiO₂ nanoparticles. The coverage of Ag shells in the prepared nanocomposites is 0.93. First, Ag substrates were cycled in a deoxygenated aqueous solution containing 0.1 M HCl and 1 mM TiO₂ nanoparticles from -0.3 to +0.3 V vs Ag|AgCl at 5 mV/s for 30 cycles. After this process, positively charged Ag-coated TiO₂ nanoparticles were formed in the solutions. Then a cathodic overpotential of 0.6 V from the open circuit potential (ocp) of ca. 0.68 V vs Ag|AgCl was applied under sonication to synthesize elemental Ag(0)-coated TiO₂ nanoparticles. The extremely high coverage of 0.93 in this work is notable, as compared with other methods to prepare metal-coated TiO₂ nanoparticles.