Du Xuexun, Yao Tian-Liang, Wei Qinglian, Zhang Hao, Huang Yongmin
Key Laboratory of Specially Functional Polymeric Materials and Related Technology, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.
Shanghai Institute of Space Propulsion, Shanghai 201112, P. R. China.
Chem Asian J. 2019 Sep 2;14(17):2966-2978. doi: 10.1002/asia.201900782. Epub 2019 Aug 1.
A series of Fe-Ni mixed-oxide catalysts were synthesized by using the sol-gel method for the reduction of NO by CO. These Fe-Ni mixed-oxide catalysts exhibited tremendously enhanced catalytic performance compared to monometallic catalysts that were prepared by using the same method. The effects of Fe/Ni molar ratio and calcination temperature on the catalytic activity were examined and the physicochemical properties of the catalysts were characterized by using XRD, Raman spectroscopy, N -adsorption/-desorption isotherms, temperature-programmed reduction with hydrogen (H -TPR), temperature-programmed desorption of nitric oxide (NO-TPD), and X-ray photoelectron spectroscopy (XPS). The results indicated that the reduction behavior, surface oxygen species, and surface chemical valence states of iron and nickel in the catalysts were the key factors in the NO elimination. Fe Ni O that was calcined at 250 °C exhibited excellent catalytic activity of 100 % NO conversion at 130 °C and a lifetime of more than 40 hours. A plausible mechanism for the reduction of NO by CO over the Fe-Ni mixed-oxide catalysts is proposed, based on XPS and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses.
采用溶胶-凝胶法合成了一系列用于CO还原NO的Fe-Ni混合氧化物催化剂。与采用相同方法制备的单金属催化剂相比，这些Fe-Ni混合氧化物催化剂表现出极大增强的催化性能。研究了Fe/Ni摩尔比和煅烧温度对催化活性的影响，并通过X射线衍射（XRD）、拉曼光谱、N₂吸附/脱附等温线、氢气程序升温还原（H₂-TPR）、一氧化氮程序升温脱附（NO-TPD）和X射线光电子能谱（XPS）对催化剂的物理化学性质进行了表征。结果表明，催化剂中铁和镍的还原行为、表面氧物种以及表面化学价态是NO消除的关键因素。在250℃煅烧的FeNiO在130℃时表现出100%的NO转化率和超过40小时的寿命，具有优异的催化活性。基于XPS和原位漫反射红外傅里叶变换光谱（DRIFTS）分析，提出了Fe-Ni混合氧化物催化剂上CO还原NO的合理机理。
