| 铈钛混合氧化物负载磷钨酸吸附-分解NOx性能 |
| Ce-Ti Mixed Oxides Supported H3PW12O40 for Effective Adsorption-Decomposition of NOx |
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| 摘要: 通过软化学途径合成了铈钛混合氧化物(CeO2-TiO2)载体材料,并分别通过等体积浸渍法和机械研磨法负载磷钨酸(H3PW12O40)。采用FTIR、XRD、SEM和BET比表面积测定对CeO2-TiO2及负载型多酸催化剂进行了表征;考察了负载量、负载方法、吸附温度等因素对催化剂吸附NOx效率的影响;选取吸附性能最佳的催化剂进行了NOx催化分解实验,探讨了NOx吸附-分解机理。结果表明:相对于等体积浸渍法,机械研磨法更适合此类载体负载H3PW12O40,其NOx吸附效率均高于H3PW12O40及载体本身;在0～60%的负载量范围内,随着H3PW12O40负载量的增加,负载型催化剂吸附NOx的效率呈先升后降趋势,负载量为40%时NOx吸附效率最佳,达90%;吸附过程中NOx与催化剂活性组分H3PW12O40发生作用,生成NOH+;H3PW12O40二级结构中结晶水对催化剂吸附NOx有重要作用;当温度从150 ℃升至 450 ℃时,被吸附的NOx发生分解,分解产物的组成与N2的收率均受升温速率的影响,升温速率越快,N2收率越高。向吸附分解NOx后的催化剂床层通入含有水蒸气的空气,可有效补充NOx分解过程中H3PW12O40失去的结晶水,从而恢复催化剂优良的NOx吸附分解性能,实现催化剂的有效再生利用。 |
| 关键词: 铈钛混合氧化物 磷钨酸 NOx 吸附-分解 |
| 基金项目: 国家自然科学基金(No.20576064,20776080,20911120088) 、教育部“新世纪优秀人才”支持计划(No.NECT-05-0584)、教育部博士点基金
(No.20070422087)及山东省科技计划(No.2006BS08020,2008GG10006005)资助项目。 |
| Abstract: Ce-Ti mixed oxides (CeO2-TiO2) were prepared as the support for solid tungstophosphoric acid (H3PW12O40). FTIR, XRD, BET surface area measurement, SEM and TPD-MS were employed for characterization and mechanism analysis. CeO2-TiO2 is an excellent support for H3PW12O40. By loading on CeO2-TiO2, the NOx adsorption efficiency of H3PW12O40 increases, with a peak efficiency of 90%, which is much higher than that of H3PW12O40 (60%). With the increase of H3PW12O40 loading, the NOx adsorption efficiency tends to reach a peak value before dropping down. The mechanical grinding method is superior to the incipient impregnation method for preparing H3PW12O40/CeO2-TiO2. In NOx adsorption process, NOx reacts with H3PW12O40 to produce NOH+. The crystal water in the secondary structure of H3PW12O40 plays an important role in NOx adsorption. The lost crystal water and oxygen vacancy can be effectively compensated by adding water vapor to regenerate the catalyst. Furthermore, the adsorbed NOx is decomposed into N2, O2 and N2O, and rapid heating contributes significantly to the decomposition of NOx over the catalyst, where a yield of 30.5% is achieved for N2 with the supported catalyst at a temperature ramp of 50 ℃·min-1. |
| Keywords: Ce-Ti mixed oxides H3PW12O40 NOx adsorption-decomposition |
| 投稿时间：2012-10-11 修订日期：2013-03-12 |
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| 程琳,王睿.铈钛混合氧化物负载磷钨酸吸附-分解NOx性能[J].无机化学学报,2013,29(6):1206-1214. |
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