抄録
Flame made gray titanium oxide particles which exhibit visible light absorption were successfully prepared via reduction atmospheric flame synthesis process. It was clarified that the particles have high specific surface area and are of nanometer size as a result of FE-SEM observation and specific surface area measurement. Particle properties could be varied by controlling equivalence ratio and introducing cooling gas, and the specific surface area increased as equivalence ratio increased. It was revealed that the particles are hollow for φ ＝ 1.54，1.68 and the constituent particles of shells are quite small in size. And the introducing of cooling gas affects the color of particles attributed to the oxidation degree and the specific surface increased as well. The result of XRD spectroscopy did not clearly show the generation of any magneli phases, however the peak intensity of anatase phase decreased which suggests the repression of oxidation. It was confirmed that carbon is rarely included in products and the change in color can be attributed not to carbon but to oxygen defect as a result of Raman spectrometry. Furthermore, the measurement of electric conductivity demonstrated the drastic improvement compared to stoichiometric titanium dioxide.
