1. Synthesis of nano-phase TiO 2 crystalline films over premixed stagnation flames and the study of the structure of these flames O.P. Korobeinichev 1, A.G. Shmakov 1, R.A. Maksyutov 1, M.L. Kosinova 2, V.S.Sulyaeva 2, A.G.Tereshchenko 1, Jong-Shinn Wu 3, Huang Chin Chen 3 1 Institute of Chemical Kinetics and Combustion of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia; 2 Institute of Inorganic Chemistry of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia; 3 National Chiao Tung University, Hsinchu, Taiwan Introduction Nanocrystalline titania (TiO 2 ) films represent a new class of functional materials, which are promising for producing dye sensitized solar cells and gas-sensors. Nanocrystalline TiO 2 films may be synthesized using different methods; however, synthesis of such materials is traditionally carried out in more than a single step. The method of synthesizing particles in one-dimensional laminar premixed ethylene-oxygen stagnation flame, stabilized at a small distance beneath a stationary cooled surface of a rotating disk was proposed early by H. Wang and co-workers [ Proc. Comb. Inst. 32 (2009) 1839–1845 ]. The objective of this study are:  to synthesize specimens of nanocrystalline titania (TiO 2 ) films in carbon-free H 2 /O 2 /Ar flame  to study of the H 2 /O 2 /Ar flame structure  to explore structure and properties of the TiO 2 films 33 th International Symposium on Combustion, August 1-6, 2010 Tsinghua University, Beijing, China Experimental setup The Russian Foundation of Basic Research is acknowledged for the support of this work under grant # 10-03-00442. Acknowledgements Air Ar H2H2 O2O2 MFC To mass- spectrometer Combustible mixture: H 2 /O 2 /Ar (13%/14.5%/ 72.5% )+ 0.1% Ti(OC 3 H 7 ) 4 syringe stepper motor heater syringe needle probe unit flame substrates Rotating disk Ti(OC 3 H 7 ) 4 Cooling airflow burner probe positioner shroud flow 300 RPM H 2 /O 2 /Ar Flame structure Properties of nanocrystalline TiO 2 films Problems in temperature and species measurements Ceramic pipes Modeling of H 2 /O 2 /Ar flame structure Problem: The quartz microprobe was clogged by TiO 2 particles in doped flame Solution: discontinuous purge of orifice by tungsten wire (0.05mm) from inside of microprobe Problem: The flame disturbed by a thermocouple and a probe Solutions: a)Using thin thermocouples (  <0.03 mm) b)b) probing along burner’s axis on its periphery The microprobe with tungsten wire inside. Probe unit with electro- magnet and controller U=4.3 m/s (T=150 o C ) The thermocouple unit  OPPDIF Code from the Chemkin II Suite  GRI 3.0 mechanism / G.P. Smith, D.M. Golden, M. Frenklach, N.W. Moriarty, B. Eiteneer, M. Goldenberg, C.T. Bowman, R.K. Hanson, S. Song, W.C. Gardiner Jr., V.V. Lissianski, Z. Qin, GRI Mech 3.0. 1999. http://www.me.berkeley.edu/gri_mech/ HRTEM images of TiO 2 particles deposited on carbon film. Average net film growth rate about 1.4 μm/s Exposition time - 10 s Exposition time - 20 s Exposition time - 30 s Medium diameter =12 nm, σ=1.45 HRTEM images of TiO 2 layers: spherical crystalline particles! Particle size distribution function of TiO 2 particles produced at 0.1% Ti(OC 3 H 7 ) 4 loading (symbols – experiment, curves – lognormal fits to data) Ultra-narrow size distribution O O O Ti O CH CH 3 CH CH 3 CH CH 3 CH CH 3 titanium tetraisopropoxide, Ti(OC 3 H 7 ) 4 XRD spectra of nano-phase TiO 2 crystals (black line), reference data for anatase (red line) and rutile (blue line). Phase-pure anatase (>95%) particles  =0.45, D=[O 2 ]/([O 2 ]+[Ar])=0.165 Concentration and temperature profiles in H 2 /O 2 /Ar flame without additive (a) and with 0.1% Ti(OC 3 H 7 ) 4 (b, c), measured at distance 2.5 mm along burner's axis. Symbols – experiments, solid thick curves – modeling Model satisfactorily agrees with experimental data a c b