Facile one-step synthesis of Ag@CeO2 core–shell nanospheres with efficient catalytic activity for the reduction of 4-nitrophenol
Abstract
Ag@CeO2 core–shell nanospheres were synthesized by a facile one-step solvothermal route from Ce(NO3)3·6H2O, AgNO3, poly(N-vinylpyrrolidone) (PVP), and ethanol. The structure, composition, BET specific surface area and optical properties of Ag@CeO2 core–shell nanospheres were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, N2 adsorption–desorption isotherm analysis, and UV-vis diffuse reflectance spectroscopy. Field emission scanning, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy etching results of the as-synthesized Ag@CeO2 nanospheres revealed that the as-synthesized Ag@CeO2 nanospheres consist of a Ag core and a CeO2 shell. The catalytic results demonstrated that the as-synthesized Ag@CeO2 nanospheres possessed higher catalytic activity than pure Ag (which was synthesized by a similar solvothermal method) in the reduction of 4-nitrophenol. Their enhanced catalytic activity is found to be due to the unique oxidized Ag species induced by the strong interaction between the core surface of Ag nanospheres and surface defects (oxygen vacancies) of the CeO2 shell. The herein proposed Ag@CeO2 core–shell nanospheres are promising catalytic candidates for the reduction of p-nitrophenol because of their simple preparation route and high catalytic activity.