title: Enhanced electron transfer and silver-releasing suppression in Ag-AgBr/titanium-doped Al2O3 suspensions with visible-light irradiation.
abstract: Ag-AgBr was deposited onto mesoporous alumina (MA) and titanium-doped MA by a deposition-precipitation method. The photocatalytic activity and the dissolution of Ag(+) from different catalysts were investigated during the photodegradation of 2-chlorophenol (2-CP) and phenol in ultrapure water and tap water with visible-light irradiation. With the increase in doped titanium, the Ag(+) dissolution decreased with a decrease in the photocatalytic activity. Ag-AgBr/MA-Ti1 was considered the better catalyst for practical applications because its Ag(+) dissolution was minimal (0.4 mg L(-1) in ultrapure water and 5 μg L(-1) in tap water), although its photoactivity was slightly less than that of Ag-AgBr/MA. The dissolution of Ag(+) was related to a charge-transfer process based on the study of cyclic voltammetry analyses under a variety of experimental conditions. The results suggested that several types of anions in the water, including CO(3)(2-), SO(4)(2-), and Cl(-), could act as electron donors that trap the photogenerated holes on Ag nanoparticles to facilitate electron circulation; this would decrease the release of Ag(+). Our studies indicated that the catalyst had a higher activity and stability in water purification.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Zhou
authors.forename: Chun
authors.initials: C
authors.lastname: Hu
authors.forename: Xuexiang
authors.initials: X
authors.lastname: Hu
authors.forename: Tianwei
authors.initials: T
authors.lastname: Peng
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002384:Catalysis; D004583:Electrons; D008027:Light; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry*; D012995:Solubility; D014025:Titanium / Q000737:chemistry*
chemical_list: D012834:Silver; D014025:Titanium; D000537:Aluminum Oxide