Ren Zhixiang, Zhang Hongliang, Wang Guangying, Pan Youchun, Yu Zhengwei, Long Hongming
School of Metallurgical Engineering, Anhui University of Technology, Maanshan 243002, China.
Key Laboratory of Metallurgical Emission Reduction & Resources Recycling, Ministry of Education, Anhui University of Technology, Maanshan 243002, China.
ACS Omega. 2020 Dec 16;5(51):33357-33371. doi: 10.1021/acsomega.0c05194. eCollection 2020 Dec 29.
In this study, anatase TiO-supported cerium, manganese, and ruthenium mixed oxides (CeO -MnO -RuO /TiO; CMRT catalysts) were synthesized at different calcination temperatures via conventional impregnation methods and used for selective catalytic reduction (SCR) of NO with NH. The effect of calcination temperature on the structure, redox properties, activation performance, surface-acidity properties, and catalytic properties of the CMRT catalysts was investigated. The results show that the CMRT catalyst calcined at 350 °C exhibits the most efficient low-temperature (<120 °C) denitration activity. Moreover, the selective catalytic oxidation (SCO) reaction of ammonia is intensified when the reaction temperature is >200 °C, which leads to a decrease in the N selectivity of the CMRT catalysts and further results in an increase in the production of NO and NO byproducts. X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy show that the CMRT catalyst calcined at 350 °C contains more Ce, Mn, Ru, and lattice oxygen, which greatly improve the catalyst's ability to activate NO that promotes the NH-SCR reaction. The Ru sites of the CMRT catalyst calcined at 250 °C are the competitive adsorption sites of NO and NH molecules, while those of the CMRT catalyst calcined at 350 and 450 °C are active sites. Both the Langmuir-Hinshelwood (L-H) mechanism and the Eley-Rideal (E-R) mechanism occur on the surface of the CMRT catalyst at the low reaction temperature (100 °C).
在本研究中，通过传统浸渍法在不同煅烧温度下合成了锐钛矿型TiO负载的铈、锰和钌混合氧化物（CeO -MnO -RuO /TiO；CMRT催化剂），并将其用于NH对NO的选择性催化还原（SCR）。研究了煅烧温度对CMRT催化剂的结构、氧化还原性能、活化性能、表面酸性性能和催化性能的影响。结果表明，在350℃煅烧的CMRT催化剂表现出最有效的低温（<120℃）脱硝活性。此外，当反应温度>200℃时，氨的选择性催化氧化（SCO）反应加剧，这导致CMRT催化剂的N选择性降低，进而导致NO和NO副产物的产量增加。X射线光电子能谱和原位漫反射红外傅里叶变换光谱表明，在350℃煅烧的CMRT催化剂含有更多的Ce、Mn、Ru和晶格氧，这大大提高了催化剂活化NO的能力，促进了NH-SCR反应。在250℃煅烧的CMRT催化剂的Ru位点是NO和NH分子的竞争吸附位点，而在350℃和450℃煅烧的CMRT催化剂的Ru位点是活性位点。在低反应温度（100℃）下，Langmuir-Hinshelwood（L-H）机理和Eley-Rideal（E-R）机理都在CMRT催化剂表面发生。
