Cui Hua-Fei, Li Cai-Ting, Lu Pei, Peng Dun-Liang, Guo Jing, Chen Ling
(Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
Huan Jing Ke Xue. 2010 Nov;31(11):2575-81.
The catalysts were prepared by activated carbon fiber (ACF) loaded different contents of NiO and NiO-CeO2, Urea was loaded on the prepared catalysts as reductant. The experiments of selective catalytic reductions (SCR) of NO were carried out from 30 to 120 degrees C. The experiments of SEM, BET and XRD of the samples were also carried out selectively to study the catalysts properties, respectively. The experimental results showed that the loaded mass fraction of NiO could greatly affect the catalytic activity of the catalysts. 10% NiO catalyst activity and activity stability were both higher than that of the others, and it could yield about 50% removal efficiency of NO at 90 degrees C. With the loaded mass increasing, the catalytic activity was obviously decreased. And furthermore, the catalyst of 5% NiO-5% CeO2/ACF had the best catalytic activities on SCR NO and stability among the prepared NiO-CeO2/ACF catalysts, and its NO removal efficiency was over 55% at 110 degrees C. When the loaded mass increased, the similar phenomenon was observed, which was due to the decreasing of specific surface area of the catalysts. The metal oxides, loaded on ACF, were the catalytic centers in this study. Moreover, 5% CeO2-5% NiO/ACF had the highest catalytic activity than 10% CeO2/ACF and 10% NiO/ ACF. Therefore, there should be synergistic effect between CeO2 and NiO. Finally, the catalytic mechanism of SCR on NO at low temperature was discussed.
催化剂由负载不同含量NiO和NiO-CeO₂的活性炭纤维（ACF）制备而成，尿素作为还原剂负载在制备好的催化剂上。在30至120℃下进行了NO的选择性催化还原（SCR）实验。还分别选择性地对样品进行了扫描电子显微镜（SEM）、比表面积（BET）和X射线衍射（XRD）实验，以研究催化剂性能。实验结果表明，NiO的负载质量分数会极大地影响催化剂的催化活性。10%NiO催化剂的活性和活性稳定性均高于其他催化剂，在90℃时其NO去除效率可达约50%。随着负载量增加，催化活性明显降低。此外，在制备的NiO-CeO₂/ACF催化剂中，5%NiO-5%CeO₂/ACF对SCR NO具有最佳的催化活性和稳定性，在110℃时其NO去除效率超过55%。当负载量增加时，观察到类似现象，这是由于催化剂比表面积减小所致。在本研究中，负载在ACF上的金属氧化物是催化中心。此外，5%CeO₂-5%NiO/ACF比10%CeO₂/ACF和10%NiO/ACF具有更高的催化活性。因此，CeO₂和NiO之间应存在协同效应。最后，讨论了低温下SCR对NO的催化机理。
