Fengyu Shen

Enhanced Photocatalytic Activity of ZnO Microspheres via Hybridization with CuInSe2 and CuInS2 Nanocrystals

ZnO microspheres sensitized by CuInSe(2) and CuInS(2) nanoparticles, which were synthesized by a solvothermal method and have a size about 20 and 3.5 nm, respectively, were used to a photodegradation of rhodamine B under an irradiation of mercury lamp. Results show that the photocatalytic activities of the ZnO/CuInSe(2) and the ZnO/CuInS(2) are much higher than that of the ZnO microspheres because of a formation of the heterojunction in two systems. It is also noted that the ZnO/CuInS(2) exhibits a higher photocatalytic activity than the ZnO/CuInSe(2), which is probably related to more suitable band gap to sunlight for CuInS(2) nanocrystals and the larger specific surface due to a small size. Particularly, the ZnO/CuInSe(2)/CuInS(2) shows the highest photocatalytic activities in all measured photocatalysts, which should be attributed to the formation of double heterojunctions among ZnO, CuInSe(2), and CuInS(2).

Ag–ZnO composite nanocrystals: synthesis, characterisation and photocatalytic properties

Abstract Ag–ZnO composite nanocrystals were prepared by a simple hydrolysis process of zinc acetate dihydrate together with a reduction of the Ag ions in diethylene glycol. Different contents of sodium hydroxide were added into the initial reaction mixture so as to form an effective contact between Ag and ZnO. X-ray diffraction analysis, ultraviolet–visible spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy and transmission electron microscopy were used to characterise the structural and morphological properties of the derived nanoparticles. The effects of the content of sodium hydroxide on the structural and morphological properties of the derived nanoparticles were discussed in detail. Photocatalytic measurement was also conducted, and the results indicate that the sample derived from 0·2M NaOH has the best ultraviolet photocatalytic activity for the degradation of the methyl orange aqueous solution among all the samples, which should be ascribed to the heterostructure formed between Ag and ZnO as well as a good dispersity of the nanoparticles.