Enhanced ultraviolet photocatalytic activity of Ag/ZnO nanoparticles synthesized by modified polymer-network gel method

Ag/ZnO nanoparticle (NP) heterostructures are synthesized through a modified polymer-network gel method in which glucose is added to the precursor solution to prevent the gel from drastically shrinking during drying of the aqueous solution. Structural and optical properties of the samples are characterized by a range of techniques including XRD, SEM, TEM, XPS, UV-Vis, and PL. The high-quality Ag-ZnO heterostructure is evidenced clearly by high-resolution TEM. The Ag/ZnO heterostructure nanocomposites exhibit a higher photocatalytic activity in the degradation of methyl orange than pure ZnO. Especially, Ag/ZnO NP heterostructures with the Ag/Zn molar ratio of 5:95 (sample ZA-5) show the highest degradation efficiency, which is 11 times higher compared with pure ZnO. The photoluminescence properties of the heterostructures and O defect states are studied to well explain the observed photocatalytic effects. ZA-5 also exhibits competitive photocatalytic activity for the degradation of other pollutant dyes such as Methylene blue and Rhodamine B compared with the recently reported techniques, while showing excellent catalyst photostability as well as offering simplicity and reliability.