Experimental Study & Theoretic Analysis Of Nanosized TiO₂/Carbon Black Prepared By Flame CVD

Nanomaterials are attracting more and more researchers because of their excellent characteristics and high performances in many fields, such as Catalysis, Electronics, Thermodynamics and so on. There are many ways to prepare nanomaterials,the CVD process is one of the most processing techniques. However, as it requires complex equipments as well as expensive raw materials, the CVD process has been confined in a narrow field. In this thesis, to conquer these shortcomings, a propane/air flame CVD process is projected to prepare nanomaterials. The main points are as the flowing:10-40nm of high purity carbon black has been synthesized by industry propane/O2 flame and propane/air flame in both gasification regime and prolysis regime. The effect of fuel/02 ration has been investigated on the DBP and pH values, particle size and morphology. The experimental results show that the carbon black synthesized in gasification regime is suitable as filler materials, whereas, the carbon black synthesized in prolysis regime has higher performance in conductivity and wear.Soot formation and growth in propane/air diffusion fames in a wide range of mole ratio of propane to air from 0.01 to 0.1 have been studied experimentally and theoretically. The concentration of acetylene, soot yield and particle size have been measured experimentally. The growth of soot particle has been simulated from surface growth and nucleation processes with a first-order surface reaction and a first-order nucleation. The rate coefficient of surface growth has been correlated with the mole ratio of propane to air and comparisons have been made on particle size between measured and calculated results.Titanium dioxide (Ti02) nanoparticles were synthesized by the oxidation of titanium tetrachloride (TiCL,), in propane/air diffusion flame. The propane/air diffusion flame is generated using a multi-port diffusion type burner composed of 4 concentric tubes. Flow rates of TiCL, and combustion gases such as air, industrial propane and carrier gas were chosen as key experimental variables for the control of the particle size and morphology. Effects of propane/air mole ratio and precursor' s flow rate on particle size, morphology, structure and carbon dots of titanium particles were studied.