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基于ZrO2/TiO2催化H2O2氧化低温脱硝的实验研究
Experimental study on low temperature H2O2 oxidative denitrification over ZrO2/TiO2 catalyst
【摘要】 以纳米TiO2为载体,采用等体积浸渍法掺杂过渡金属氧化物ZrO2进行改性,制备了一系列ZrO2/TiO2催化剂,以催化H2O2低温氧化NO脱硝,并采用X射线衍射(XRD)、H2程序升温还原(H2-TPR)、O2程序升温氧化(O2-TPO)、X射线光电子能谱(XPS)及电子顺磁共振(EPR)等表征分析探究了影响H2O2脱硝活性的因素.表征结果表明ZrO2的负载量会影响催化剂中晶格氧的含量,晶格氧相对含量的增加有利于氧化还原反应中的电子传递,这是促进H2O2活化分解的关键.在微观表征的基础上,通过实验研究筛选获得了催化剂的最佳ZrO2负载量,同时对比考察了非催化和纳米TiO2催化作用下的H2O2氧化低温脱硝性能;针对获取的最优催化剂,进一步考察了不同烟气工况对催化剂活性的影响.实验结果表明,ZrO2/TiO2催化剂能有效促进H2O2的活化分解实现低温脱硝,且ZrO2负载量为4%(质量分数)时,催化活性最高;在烟温为160℃、[H2O2]/[NO]物质的量比为2及空速为30000 h-1时,NO转化率最高可达81%.
【Abstract】 A series of ZrO2/TiO2 catalysts were prepared by incipient wetness impregnation method to catalyze the low-temperature oxidation denitrification by H2O2. The characterization analyses of X-ray diffraction(XRD), H2-temperature programmed reduction(H2-TPR), O2-temperature programmed oxidation(O2-TPO), X-ray photoelectron spectroscopy(XPS) and electron paramagnetic resonance(EPR) were performed to explore the factors affecting the denitrification activity of H2O2. The characterization results showed ZrO2 loading will affect the content of the lattice oxygen in the catalyst. The increase of lattice oxygen relative content is beneficial to the electron transfer during redox reaction, which is the key to promote the decomposition of H2O2. The optimum ZrO2 loading of the catalyst was obtained by experimental research. And the performance of ZrO2/TiO2 catalyzed H2O2 oxidative denitrification was compared with that of non-catalytic and nano-TiO2. The effect of flue gas conditions on the catalyst activity was further investigated. The results showed that ZrO2/TiO2 catalyst could effectively promote the decomposition of H2O2 to realize low temperature denitrification. The best catalytic performance was obtained at ZrO2 loading of 4%. Under the flue gas temperature of 160 ℃, [H2O2]/[NO] molar ratio of 2 and space velocity of 30000 h-1, the NO conversion reached as high as 81%.
【Key words】 H2O2; NO oxidation; ZrO2/TiO2; low temperature denitrification;
- 【文献出处】 环境科学学报 ,Acta Scientiae Circumstantiae , 编辑部邮箱 ,2019年02期
- 【分类号】X701
- 【网络出版时间】2018-08-27 15:35
- 【被引频次】4
- 【下载频次】156