title: Hydrothermal Synthesis of TiO2@SnO2 Hybrid Nanoparticles in a Continuous-Flow Dual-Stage Reactor.
abstract: TiO2@SnO2 hybrid nanocomposites were successfully prepared in gram scale using a dual-stage hydrothermal continuous-flow reactor. Temperature and pH in the secondary reactor were found to selectively direct nucleation and growth of the secondary material into either heterogeneous nanocomposites or separate intermixed nanoparticles. At low pH, 2 nm rutile SnO2 nanoparticles were deposited on 9 nm anatase TiO2 particles; the presence of TiO2 was found to suppress formation of larger SnO2 particles. At high pH SnO2 formed separate particles and no deposition on TiO2 was observed. Ball-milling of TiO2 and SnO2 produced no TiO2@SnO2 composites. This verifies that the composite particles must be formed by nucleation and growth of the secondary precursor on the TiO2 . High concentration of secondary precursor led to formation of TiO2 particles embedded in aggregates of SnO2 nanoparticles. The results demonstrate how nanocomposites may be produced in high yield by green chemistry.
authors.affiliation: Center for Materials Crystallography, Department of Chemistry, Aarhus University, Langelangsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Henrik L
authors.initials: HL
authors.lastname: Hellstern
authors.affiliation: Center for Materials Crystallography, Department of Chemistry, Aarhus University, Langelangsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Bremholm
authors.affiliation: Center for Materials Crystallography, Department of Chemistry, Aarhus University, Langelangsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Aref
authors.initials: A
authors.lastname: Mamakhel
authors.affiliation: Center for Materials Crystallography, Department of Chemistry, Aarhus University, Langelangsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Becker
authors.affiliation: Center for Materials Crystallography, Department of Chemistry, Aarhus University, Langelangsgade 140, 8000, Aarhus C, Denmark. bo@chem.au.dk.
authors.forename: Bo B
authors.initials: BB
authors.lastname: Iversen
mesh_terms: D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles; D017348:Microscopy, Electron, Scanning Transmission; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D017971:Tin Compounds / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D017971:Tin Compounds; C009495:titanium dioxide; D014025:Titanium; C045358:stannic oxide
keywords: composites; hybrid materials; hydrothermal synthesis; nanoparticles; oxides