Light still remains an exotic tool for the control of particle shape, size and composition, even though light-mediated synthesis provides advantages of a uniform distribution of the reducing agent and tunable wavelength with... [ view full abstract ]
Light still remains an exotic tool for the control of particle shape, size and composition, even though light-mediated synthesis provides advantages of a uniform distribution of the reducing agent and tunable wavelength with regard to the conventional chemical approaches. On the other hand, utilization of solar energy for catalytic chemical transformations has been considered as an environmentally friendly alternative to traditional thermally driven heterogeneous catalysis for decades [1,2]. The aim of this work was to prepare and characterize Ag-CeO2 system,a potential photocatalyst with the visible light activity, via photochemical inorganic synthesis.
Synthesis of Ag-CeO2 was carried out in deaerated aqueous CeO2 dispersions containing dissolved AgNO3. Metallic silver was photocatalytically generated on the surface of ceria as a result of UV irradiation with 0 W mercury discharge lamp NIQ40/18–45000024. Irradiation of deaerated CeO2 suspensions in the presence of AgNO3 resulted in the rise of a strong band with the maximum at 391 – 422 nm in the absorption spectra of the solutions. Faster formation of Ag nanoparticles with the lower amount of silver being required was observed when ethanol was introduced to the reaction solution before the irradiation. Alcohols with α-hydrogens are known to easily form α-hydroxyalkylradicals upon α-H atom abstraction. Hence, reductive reactions can be strongly enhanced in deaerated ethanol containing solutions with respect to the pure aqueous media.
Not only is the proposed synthesis pathway a clean route to the formation of the nanoparticles with no potential damage to the environment being expected, it also provides the possibility to create small uncoated nanostructures with a “clean” surface. From the viewpoint of applications, any residue of amines, polymers or organic solvents, which are usually required in a photochemical synthesis mixture, should affect the performance of the nanoparticles significantly. Thus, the proposed photochemical approach with no additives, but uncoated ceria nanoparticles being required, should enable us to produce particles with remarkably improved photocatalytic properties.
1. A. Fujishima and K. Honda. Nature, 1972. 238(5358): 37-38
2. M.J.Kale, T. Avanesian, P. Christopher. ACS Catalysis, 2014. 4(1): 116-128.
