Ag@ZnO Core-Shell Nanoparticles Formed by the Timely Reduction of Ag+ Ions and Zinc Acetate Hydrolysis in N,N-Dimethylformamide: Mechanism of Growth and Photocatalytic Properties

MATÍAS E. AGUIRRE; HERNÁN B. RODRÍGUEZ; ENRIQUE SAN ROMÁN; ARMIN FELDHOFF; MARÍA A. GRELA

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2011 vol. 115 p. 24967 - 24974

1932-7447

A new synthetic route for the preparation of Ag@ZnO hybrid nanostructures under well-defined conditions using silver nitrate and zinc acetate in N,N-dimethylformamide as starting materials is presented. The solvent simultaneously behaves as a reducing agent for Ag + ions and provides the basic medium for zinc acetate hydrolysis at room temperature, with-out making resource of stabilizers and any kind of additives. As determined by electron microscopy studies, the prepared nanostructures have well-defined core?shell architectures, with a cover layer of ZnO protecting the Ag center from oxidation by external agents.Intermediates and final products were further characterizedby FTIR, XRD, ICP-OES, and UV-vis absorption and luminescence spectroscopy.The change in the emission properties of ZnO as a result of the assemblage proves the strong interaction existing between the semiconductor and the metallic nucleus and points to an efficient electron transfer from ZnO to Ag. Accordingly,comparative photocatalytic experiments of ZnO and Ag@ZnO nanostructures loaded with the chelating xanthenedye, 9-phenyl-2,3,7-trihidroxy-6-fluorone, confirm that the presence of Ag nanoparticles in the hybrid nanostructures serves to slow down charge recombination both under UV and visible light excitation.