低温下 NH3 选择性催化还原 NO 反应路径的研究。Cu/SSZ-13 催化剂。
Reaction pathway investigation on the selective catalytic reduction of NO with NH3 over Cu/SSZ-13 at low temperatures.
机构信息
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, P. R. China.
出版信息
Environ Sci Technol. 2015 Jan 6;49(1):467-73. doi: 10.1021/es503430w. Epub 2014 Dec 23.
The mechanism of the selective catalytic reduction of NO with NH3 was studied using Cu/SSZ-13. The adspecies of NO and NH3 as well as the active intermediates were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy and temperature-programmed surface reaction. The results revealed that three reactions were possible between adsorbed NH3 and NOx. NO2(-) could be generated by direct formation or NO3(-) reduction via NO. In a standard selective catalytic reduction (SCR) reaction, NO3(-) was hard to form, because NO2(-) was consumed by ammonia before it could be further oxidized to nitrates. Additionally, adsorbed NH3 on the Lewis acid site was more active than NH4(+). Thus, SCR mainly followed the reaction between Lewis acid site-adsorbed NH3 and directly formed NO2(-). Higher Cu loading could favor the formation of active Cu-NH3, Cu-NO2(-), and Cu-NO3(-), improving the SCR activity at low temperature.
采用 Cu/SSZ-13 研究了 NH3 选择性催化还原 NO 的反应机理。利用原位漫反射红外傅里叶变换光谱和程序升温表面反应技术考察了 NO 和 NH3 的吸附物种和活性中间物种。结果表明，吸附态 NH3 与 NOx 之间可能发生三种反应。NO2(-)可通过直接形成或通过 NO 还原 NO3(-)生成。在标准选择性催化还原（SCR）反应中，由于 NH3 消耗了 NO2(-)，因此难以形成 NO3(-)。此外，Lewis 酸位上吸附的 NH3 比 NH4(+)更具活性。因此，SCR 主要遵循 Lewis 酸位吸附 NH3 与直接形成的 NO2(-)之间的反应。较高的 Cu 负载量有利于生成活性 Cu-NH3、Cu-NO2(-)和 Cu-NO3(-)，从而提高低温下的 SCR 活性。
Zotero 插件