标题: | 以常压电浆辅助程序制造氮掺杂二氧化钛可见光触媒奈米微粒之研究 Production of N-doped TiO2 Photocatalysts by Atmospheric Pressure Plasma Enhanced Nanoparticle Synthesis Process |
作者: | 陈建志 Chienchih Chen 白曛绫 Hsunling Bai 环境工程系所 |
关键字: | 非热电浆;奈米微粒;光触媒;可见光光触媒;二氧化钛;气胶产生器;nonthermal plasma;nanoparticles;photocatalysis;visible light photocatalyst;titanium dioxide;aerosol generator |
公开日期: | 2007 |
摘要: | 本研究目的为利用常压电浆辅助奈米微粒制造程序(Atmospheric Pressure Plasma Enhanced Nanoparticle Synthesis;APPENS)制造均匀粒径之N掺杂TiO2奈米微粒,其可为能源材料或光触媒使用,此外亦可应用作为均匀气胶产生器(monodisperse aerosol generator),提供对奈米颗粒健康效应等研究者一个简易的奈米微粒即时产生源。 本研究利用自行开发之APPENS系统,在常温常压下,藉由各种不同制程条件之电浆反应器系统产生奈米微粒,再将所得之微粒利用SEM、TEM、XPS、XRD等仪器分析微粒之物理化学特性。研究结果显示,本程序所合成之光触媒微粒粒径分布约为20nm~40nm。经过XRD及XPS分析后确认为含氮掺杂之anatase TiO2。将制造所得之光触媒以甲苯及异丙醇为挥发性有机物指标物种进行紫外光及可见光光催化批次反应,结果显示本研究之触媒在以可见光光源照射40分钟,对甲苯及异丙醇分别有40%及100%去除效率,而在紫外光下对甲苯效率则提升为60%,对异丙醇则在30分钟内达到100%。利用连续式光催化反应来比较本研究制造得之光触媒与商用光触媒(P-25、ST01)之活性,结果显示在可见光照下确实有较优于商用触媒之去除效率。本研究亦探讨在不同制程条件下制造各种不同氮掺杂光触媒之表面键结特性,研究显示可见光触媒表面键结型态为影响光催化活性之关键,OX-Ti-NY 型态掺杂(doping)对可见光的催化效果较Ti-(NO)为佳,而无论是Ti-N、Ti-N及OX-Ti-NY 型态的氮掺杂 都有可见光的催化效果, Ti-(NO2) 型态的氮掺杂则可能会对可见光的催化效果有负影响。 研究中并针对合成程序条件对生成微粒之影响,发现在无电浆环境下形成的可见光触媒微粒会成双峰分布,其平均粒径为100 nm及400 nm; 而在电场强度9.6 kV/cm之电浆环境下形成之微粒则成单峰分布,粒径大小依不同前驱物浓度而改变,范围约在30-60 nm左右,此外改变不同电场强度及频率亦会改变粒径的分布。本研究结果显示本系统不仅能制造出高均匀度之奈米微粒,且该电浆系统具有参数调整容易之优点,可迅速的产生所需粒径之奈米微粒,且在可见光触媒制造上可获致品质佳且较其他制程应用性更广之成品。 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. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT009019519 http://hdl.handle.net/11536/82158 |
显示于类别: | Thesis |
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