title: Structure-property-composition relationships in doped zinc oxides: enhanced photocatalytic activity with rare earth dopants.
abstract: In this paper, we demonstrate the use of continuous hydrothermal flow synthesis (CHFS) technology to rapidly produce a library of 56 crystalline (doped) zinc oxide nanopowders and two undoped samples, each with different particle properties. Each sample was produced in series from the mixing of an aqueous stream of basic zinc nitrate (and dopant ion or modifier) solution with a flow of superheated water (at 450 °C and 24.1 MPa), whereupon a crystalline nanoparticle slurry was rapidly formed. Each composition was collected in series, cleaned, freeze-dried, and then characterized using analytical methods, including powder X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area measurement, X-ray photoelectron spectroscopy, and UV-vis spectrophotometry. Photocatalytic activity of the samples toward the decolorization of methylene blue dye was assessed, and the results revealed that transition metal dopants tended to reduce the photoactivity while rare earth ions, in general, increased the photocatalytic activity. In general, low dopant concentrations were more beneficial to having greater photodecolorization in all cases.
authors.affiliation: Christopher Ingold Laboratories, Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, United Kingdom.
authors.forename: Josephine B M
authors.initials: JB
authors.lastname: Goodall
authors.forename: Derek
authors.initials: D
authors.lastname: Illsley
authors.forename: Robert
authors.initials: R
authors.lastname: Lines
authors.forename: Neel M
authors.initials: NM
authors.lastname: Makwana
authors.forename: Jawwad A
authors.initials: JA
authors.lastname: Darr
mesh_terms: D002384:Catalysis; D008674:Metals, Rare Earth / Q000737:chemistry*; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry; D010316:Particle Size; D055668:Photochemical Processes; D013499:Surface Properties; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D008674:Metals, Rare Earth; D015034:Zinc Oxide
keywords: UV attenuator; continuous hydrothermal; doping; photocatalytic activity; zinc oxide