A Facile Synthesis of Ag Modified ZnO Nanocrystals with Enhanced Photocatalytic Activity

Ag modified ZnO （Ag/ZnO） nanocrystals were prepared by a facile and low temperature wet chemical method. The phase structures, morphologies, and optical properties of the as-prepared samples were characterized by X-ray powder diffraction （XRD）, field-emission scanning electron microscopy （FESEM）, high-resolution transmission electron microscopy （HRTEM）, the Brumauer-Emmett-Teller （BET） surface area, UV-vis diffuse reflectance spectroscopy and photoluminescence （PL） spectra, respectively. The photocatalytic performance of Ag/ZnO with diffent Ag contents was measured with the degradation of methyl orange （MO） at room temperature under UV light irradiation. The experimental results indicated that the well-crystalline ZnO nanopaticles with a size of ca. 4.5 nm exhibited a high photocatalytic activity for the degradation of MO with the apparent rate constant （k） of 1.57 ×10-2 min-1, and the photocatalytic activities of ZnO were further enhanced by modification with silver. When the Ag loading was 3mol%, Ag/ZnO showed the highest photocatalytic acitivity with a k value of 5.452×10-2 min-1, which is 3.5 and 2.5 time more than that of ZnO and commercial P25, respectively.