摘要
将碳纳米管(CNTs)载体分别经混酸与硝酸蒸气预处理并在不同温度下煅烧,然后分别采用浸渍法及机械研磨法负载磷钨酸(HPW),制备出HPW/CNTs催化剂,对比考察了上述催化剂对NOx的吸附与分解效果.在空速为10000 h-1、吸附温度为200℃的条件下,用0.5 g催化剂对1696 mg/m3的NOx进行吸附实验,结果表明,以硝酸蒸气预处理且经300℃煅烧后的CNTs为载体,采用机械研磨负载法制备的催化剂HPW/CNTs对NOx的吸附率与吸附能力最高,分别为54%与16.6 mg NOx/(g.h).对吸附NOx后的催化剂体系进行了催化分解NOx的程序升温脱附-质谱(TPD-MS)研究,结果表明,所吸附的NOx在快速升温过程中发生分解,在此过程中有氧产生,分解产物包括N2,O2及N2O.采用电阻炉快速加热与微波辐射2种方式分别对吸附的NOx进行催化分解,结果表明,微波功率为700 W时,NOx分解为N2的收率为33.3%,高于电阻炉以150℃/min快速升温的N2收率.使用过的催化剂通水蒸气后可实现再生,对再生后的催化剂进行循环使用研究,结果表明,再生后的催化剂吸附与催化分解NOx的性能未有明显下降.
A series of HPW/CNTs catalysts was prepared by impregnation and mechanical grinding methods. For this purpose, CNTs was pretreated separately by nitric acid vapor, mixture of nitric acid and sulphuric acid, and subsequently calcined. The performances of catalysts on NOx adsorption-decomposition were studied. The 0. 5 g catalyst was used to adsorb 1696 mg/m3 NOx under the space velocity of 1000 h-1 at 200℃, and the results showed that the catalyst prepared by mechanical grinding methods supporting HPW on CNTs pretreated by nitric acid vapor and calcined at 300℃ had the highest NOx adsorption efficiency and capacity of 54% and 16.6 mg NOx/（ g · h）. Temperature-programmed desorption-mass spectroscopy（TPD-MS） was carried out on the catalyst adsorbed NOx, and the result showed that N2, O2 and N2O were formed during rapid heating, among which O2 was observed for the first time. Two modes of decomposition were adopted, one is by electric oven at a ramping rate of 150 ℃/min, and the other, by microwave oven. Compared to the mode of the former, the latter has higher N2 yield with a N2 yield upto 33.3% corresponding to the power of microwave oven being 700 W. The catalyst used can be reused by water vapor reactivation, and the recycling results showed that there were no significant performance degradation on NOx adsorption and catalytic decomposition.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2012年第8期1826-1834,共9页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:20776080
20911120088)
教育部"新世纪优秀人才"支持计划(批准号:NCET-05-0584)
山东省科技计划(批准号:2006BS08020
2008GG10006005)资助
关键词
氮氧化物
磷钨酸
碳纳米管
微波辐射
吸附-分解
NOx
Tungstophosphoric acid
Carbon nanotubes
Microwave radiation
Adsorption-decomposition
作者简介
联系人简介：王睿，男，博士，教授，博士生导师，主要从事环境污染物催化治理研究．E-mail：ree_wong@hotmail．com
