Photocatalytic oxidation of aqueous ammonia over microwave-induced titanate nanotubes
Photocatalytic oxidation of aqueous ammonia over microwave-induced titanate nanotubes
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DOI：
10.1021/es703211u
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发表时间：
2008-06-15
影响因子：
11.4
通讯作者：
Lo, Shang-Lien
中科院分区：
文献类型：
--
作者：
Ou, Hsin-Hung;Liao, Ching-Hui;Lo, Shang-Lien
采用比表面积（S-BET）、X射线衍射（XRD）、X射线光电子能谱（XPS）、离子耦合等离子体原子发射光谱（ICP-AES）、扫描电子显微镜/能量色散X射线（SEM/EDX）和高分辨透射电子显微镜（HR-TEM）等手段对微波诱导钛酸盐纳米管（NaxH 2-xTi 3 O 7，TNTs）进行表征。在制备过程中微波辐射的应用水平是负责的钠原子到TNT的嵌入强度和类型的结晶相内的TNT，这支配了光催化NH3/NH 4+的效率。纯TNT相对NH3/NH 4+的光催化能力不强，而在TNT中存在金红石相可以提高光催化效率。此外，P25 TiO 2中的金红石相和金红石相的混合物更倾向于形成NO3-，而TNT产生更高的NO2-。酸洗处理对TNT的影响方面，增强离子交换的酸处理TNT显著提高了NH3/NH 4+的降解率和NO2-/NO3-的产率。这可能是由于NH3/NH 4+易于嵌入酸洗后的TNT结构中，从而使插层后的NH3/NH 4+的光催化氧化不受TNT过载的屏蔽效应的限制。
Characterizations of microwave-induced titanate nanotubes (NaxH2-xTi3O7, TNTs) were conducted by the determinations of specific surface area (S-BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopic (XPS), ionic coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy/energy dispersive X-ray (SEM/EDX), and high-resolution transmission electron microscopy (HR-TEM). The applied level of microwave irradiation during the fabrication process is responsible for both the intercalation intensity of Na atoms into TNTs and the type of crystallization phase within TNTs, which dominate the efficiency of photocatalytic NH3/NH4+. A pure TNT phase presents no powerful ability toward photocatalytic NH3/NH4+, while the photocatalytic efficiency can be enhanced with the presence of a rutile phase within TNTs. In addition, the mixture of anatase and rutile phase within P25 TiO2 prefers forming NO3-, whereas TNTs yield higher NO2- amount Regarding the effect of acid-washing treatment on TNTs, the acid-treated TNTs with enhanced ion exchangeability considerably improve the NH3/NH4+ degradation and NO2-/NO3- yields. This result is likely ascribed to the easy intercalation of NH3/NH4+ into the structure of acid-washing TNTs so that the photocatalytic oxidation of intercalated NH3/NH4+ is not limited to the shielding effect resulting from the overload of TNTs.