Gas-phase photocatalytic activity of nanostructured titanium dioxide from flame aerosol synthesis
Gas-phase photocatalytic activity of nanostructured titanium dioxide from flame aerosol synthesis
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DOI：
10.1016/j.apcatb.2011.09.007
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发表时间：
2012-01-12
影响因子：
22.1
通讯作者：
Deubener, Joachim
中科院分区：
文献类型：
--
作者：
Joks, Svetlana;Klauson, Deniss;Deubener, Joachim
采用火焰气溶胶反应器合成了纳米TiO 2粉体，并对其在气相光催化氧化挥发性有机物（VOCs）中的活性进行了实验评价。该纳米粉体的平均粒径为13 nm，纳米粒子含量为97 wt.%比表面积为102 m（2）g（-1）。将性能与基准光催化剂商业热解二氧化钛P25进行比较。Evonik，平均粒径为21 nm。在连续气流模式下，通过改变接触时间、污染物浓度和温度，进行了降解脂肪族丙烯腈（AN）和芳香族甲苯的全因子实验。火焰气溶胶合成的光催化剂在降解这两种污染物时，观察到更高的转化率和更稳定的性能。虽然初级颗粒尺寸和比表面积提出了在可吸附AN中改善PCO性能的明显原因，但这些参数在吸附性差的甲苯的氧化中不能做同样的事情：羟基自由基的上级生成，因此，提出了先进的氧化活性作为解释。在升高的温度（130 ℃）下，减小尺寸的微晶的强烈脱水可能导致OH-自由基产生的减少，同时沿着AN的PCO副产物HCN的解吸的改善。因此，安全性能需要更低的工作温度。讨论了火焰气溶胶合成催化剂在紫外线辐射下的慢失活和快恢复。(C)2011 Elsevier B. V.保留所有权利。
The experimental evaluation of gas-phase photocatalytic activity of a TiO2 nanopowder synthesized in a flame aerosol reactor was carried out in photocatalytic oxidation (PCO) of volatile organic compounds (VOCs). The nanopowder has an average particle size of 13 nm, anatase content 97 wt.% and the specific surface area of 102 m(2) g(-1). The performance was compared to the benchmark photocatalyst, the commercial pyrogenic titania P25. Evonik, with the average particle size of 21 nm. The full-factorial experiments were carried out varying contact times, concentrations of pollutants and temperatures in continuous gas-flow mode degrading aliphatic acrylonitrile (AN) and aromatic toluene. Higher conversions at more stable performance were observed for the flame aerosol synthesized photocatalyst in degradation of both pollutants. While the primary particle size and specific surface area present the apparent reasons for improved PCO performance in adsorbable AN, these parameters cannot do the same in oxidation of poorly adsorbable toluene: the superior generation of hydroxyl radicals and, therefore, advanced oxidative activity are proposed as explanation. The intense dehydration of reduced size anatase crystallites at elevated temperature (130 degrees C) presumably resulted in decreased OH-radicals production along with the improved desorption of HCN, the PCO by-product of AN. The safe performance is thus requiring lower operational temperatures. Slower deactivation and faster restoration of catalytic activity of flame aerosol synthesized catalyst under UV-A-radiation are discussed. (C) 2011 Elsevier B.V. All rights reserved.