Comparison of T-piece and concentric mixing systems for continuous flow synthesis of anatase nanoparticles in supercritical isopropanol/water

• Published in: Journal of solid state chemistry 2009-03, Vol.182 (3), p.491-495
• Main Authors: Toft, Lars L., Aarup, David F., Bremholm, Martin, Hald, Peter, Iversen, Bo B.
• Format: Article
• Language: English
• Subjects: Absolute crystallinity; Condensed matter: structure, mechanical and thermal properties; CRITICAL TEMPERATURE; Cross-disciplinary physics: materials science; rheology; DISTRIBUTION; Exact sciences and technology; FLOW RATE; GEOMETRY; Growth from solutions; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Mixing geometry; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; NANOSTRUCTURES; Other topics in nanoscale materials and structures; PARTICLE SIZE; Physics; PROPANOLS; Size distributions; SMALL ANGLE SCATTERING; Structure of solids and liquids; crystallography; Supercritical fluids; SYNTHESIS; TEMPERATURE DEPENDENCE; TITANIUM OXIDES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; X-ray diffraction and scattering; X-ray scattering (including small-angle scattering)
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2008.11.009

T-piece and concentric counter-flow mixing systems are compared in continuous flow supercritical solvothermal synthesis of TiO 2 at identical system parameters. The phase pure anatase nanoparticle products were characterized with powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS), and the particle size, size distribution and absolute crystallinity mapped as a function of temperature, precursor concentration, flow rate and pressure for the two different continuous flow reactors. The particles synthesized with the T-piece geometry are smaller with a narrower size distribution, possibly indicating a more effective mixing, than particles synthesized at the same conditions with concentric counter-flow geometry. In general, an increased synthesis temperature leads to an increase in absolute crystallinity. For the particles synthesized with the concentric reactor geometry crossing of the critical point of the solvent causes a decrease in the particle size and size distribution, and conditions just above the critical temperature are demonstrated to be optimal for continuous solvothermal synthesis of anatase. Direct experimental comparison of T-piece and concentric mixing geometries in supercritical continuous flow synthesis of anatase nanoparticles.