Nozzle‐quenching process for controlled flame synthesis of titania nanoparticles

A process for precisely controlled synthesis of nanoparticles with a broad range of sizes, morphologies, and phase compositions is presented. This is achieved by a rapid quenching of the entire flame aerosol in a critical-flow nozzle placed above and into the flame. This process is evaluated for synthesis of titania nanoparticles by oxidation of titanium-tetra-isopropoxide (TTIP) in a methane/oxygen coflow diffusion-flame reactor. Precise control of phase composition from 97 to 5 wt. % anatase (and the balance rutile) and average primary particle diameter from 5 to 60 nm is possible by positioning the quenching nozzle at the desired heights above the burner and controlling gas and precursor flow rates. The nozzle quenching also reduces the degree of agglomeration of the product particles. An operation diagram shows that the primary particle diameter and the phase composition can be independently controlled, making anatase or rutile nanoparticles with high or low specific surface area.

[1]  J. Hansen,et al.  Synthesis of ZnO particles in a quench‐cooled flame reactor , 2001 .

[2]  H. F. Calcote,et al.  A new flame process for synthesis of Si3N4 powders for advanced ceramics , 1991 .

[3]  Irvin Glassman,et al.  A gas-phase combustion synthesis process for non-oxide ceramics , 1992 .

[4]  Patricia Layman,et al.  French Chemical Industry Completes Massive Restructuring: Regrouping of activities has greatly simplified industry's tangled structure; question remains if and when move will translate into higher profits , 1984 .

[5]  P. Roth,et al.  Formation and Growth of Sio2 Particlesin Low Pressure H2/O2/Ar Flames Doped with Sih4 , 1997 .

[6]  S. Pratsinis,et al.  Computational analysis of coagulation and coalescence in the flame synthesis of titania particles , 2001 .

[7]  Y. Iida,et al.  Grain Growth and Phase Transformation of Titanium Oxide During Calcination , 1961 .

[8]  Sotiris E. Pratsinis,et al.  Flame Aerosol Synthesis of Vanadia–Titania Nanoparticles: Structural and Catalytic Properties in the Selective Catalytic Reduction of NO by NH3 , 2001 .

[9]  J. Katz,et al.  Formation of mixed oxide powders in flames: Part I. TiO_2−SiO_2 , 1992 .

[10]  S. Friedlander,et al.  Particle Growth by Coalescence and Agglomeration , 1991 .

[11]  Sotiris E. Pratsinis,et al.  Flame aerosol synthesis of ceramic powders , 1998 .

[12]  William Felder,et al.  A new gas-phase combustion synthesis process for pure metals, alloys, and ceramics , 1992 .

[13]  R. W. Cheary,et al.  A fundamental parameters approach to X-ray line-profile fitting , 1992 .

[14]  E. R. Place,et al.  Formation of TiO2 aerosol from the combustion supported reaction of TiCl4 and O2 , 1973 .

[15]  G. D. Ulrich,et al.  Particle Growth in Flames. II: Experimental Results for Silica Particles , 1976 .

[16]  Wenhua H. Zhu,et al.  The role of gas mixing in flame synthesis of titania powders , 1996 .

[17]  Wenhua H. Zhu,et al.  Flame Synthesis of Nanosize Powders: Effect of Flame Configuration and Oxidant Composition , 1996 .

[18]  H. Haerudin,et al.  Surface stoichiometry of ‘titanium suboxide’ , 1998 .

[19]  W. Stark,et al.  Flame-nozzle synthesis of nanoparticles with closely controlled size, morphology and crystallinity , 2002 .

[20]  S. Friedlander,et al.  Controlled Synthesis of Nanosized Particles by Aerosol Processes , 1993 .

[21]  Min Huang,et al.  Microstructural Characterization of a Fumed Titanium Dioxide Photocatalyst , 1995 .

[22]  B. Kear,et al.  Scalable high-rate production of non-agglomerated nanopowders in low pressure flames , 1998 .

[23]  J. Katz,et al.  Titania and silica powders produced in a counterflow diffusion flame , 1996 .

[24]  S. Pratsinis,et al.  AEROSOL-BASED FLAME SYNTHESIS: A MICROREACTOR FOR SILICA NANOPARTICLES , 2002 .

[25]  R. Axelbaum,et al.  Nanoscale unagglomerated nonoxide particles from a sodium coflow flame , 1995 .

[26]  P. Mériaudeau,et al.  Preparation in a hydrogen-oxygen flame of ultrafine metal oxide particles. Oxidative properties toward hydrocarbons in the presence of ultraviolet radiation , 1972 .

[27]  Constantine M. Megaridis,et al.  Morphology of flame-generated soot as determined by thermophoretic sampling , 1987 .

[28]  H. Jang,et al.  Controlled synthesis of titanium dioxide nanoparticles in a modified diffusion flame reactor , 2001 .

[29]  S. Pratsinis,et al.  Monitoring the flame synthesis of TiO2 particles by in-situ FTIR spectroscopy and thermophoretic sampling , 2001 .

[30]  S. Andersson,et al.  PHASE ANALYSIS STUDIES ON THE TITANIUM-OXYGEN SYSTEM , 1957 .