Production of N-doped TiO2 Photocatalysts by Atmospheric Pressure Plasma Enhanced Nanoparticle Synthesis Process

• Main Authors: Chienchih Chen, 陳建志
• Other Authors: Hsunling Bai
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/91151200537979383991

博士 === 國立交通大學 === 環境工程系所 === 96 === An Atmospheric Pressure Plasma Enhanced Nanoparticle Synthesis (APPENS) process was proposed to produce nitrogen doped (N-doped) titanium dioxide (TiO2) visible light photocatalyst. The effect of N-doping statuses on the photocatalytic activity of N-doped TiO2 photocatalysts was investigated. The potential application of APPENS reactor as an aerosol generator was studied. The results showed that photocatalytic activity of the N-doped TiO2 photocatalyst is higher than the commercial ST01 and P25 photocatalysts in terms of toluene removals in a continuous flow reactor. The light absorption in the visible light range for N-doped TiO2 was also confirmed by a clear red shift of the UV-visible spectra. The N-doped TiO2 particles with OX-Ti-NY and -(NO) dopants are produced via N2 plasma gas followed by air or N2 annealing gases. They have better visible and UV photocatalytic activities as compared to the pure TiO2 photocatalysts prepared under O2/Ar plasma and annealing gases. The results reveal that the OX-Ti-NY and -(NO) dopants may have positive effects on the visible light photocatalytic activity while the -(NO2) dopant tends to have a negative effect on the visible light photocatalytic activity. For the aerosol generator employs the APPENS process of alternative current (AC), the influences of applied voltage, frequency and molar ratios of precursor on the generated particles were characterized by the SEM, XRD and SMPS analyses. Results showed that TiO2 nanoparticles appear to be in a broad size range of bi-modal distribution when no voltage is applied. After applying the AC plasma, uni-modal distribution with average sizes range of 30-60 nm was observed. The applied electric frequency can be adjusted to either generate nanoparticles after the plasma reactor or develop a thin film in the reactor. An increase in the precursor molar ratio leads to larger particles with a broader size distribution.