Abstract：A series of MnOx/ZSM-5 (H-ZSM-5, Na-ZSM-5 and NH4-ZSM-5) catalysts were synthesized by wet impregnation method and their catalytic activities were investigated for selective catalytic reduction of NOx with NH3 (NH3-SCR). The effect of the equilibrium ion on the catalytic performance and the physicochemical property of the samples were studied. Remarkably, the ions (H+, Na+ and NH4+) greatly influenced the deNOx ability of the catalysts. When NH4-ZSM-5was adopted as the support, the catalyst exhibited the excellent the low-temperature SCR activity, while MZ-H catalyst showed better NOx conversion at high temperature. The physicochemical properties of the samples were characterized using XRD, TEM, H2-TPR, XPS, N2 adsorption/desorption and Raman spectra. For MZ-NH4 catalyst, MnOx were mainly dispersed on the external surface of ZSM-5 and obvious agglomeration could be observed. In this case, Mn3+ oxide state was dominant in the catalyst, resulting in the strong oxidation of NO to NO2, which consequently enhanced “fast reaction”. For MZ-H catalyst, MnOx nanoparticles were confined in the channels of zeolite support and the available active sites were less, which was the reason for the poor catalytic activity at low temperature. The location of MnOx nanoparticles and the redox property of MnOx/ZSM-5 catalysts were affected by the equilibrium ion in zeolite, and the active components were dispersed on the outside of zeolite, which was benefited for the NH3-SCR at low temperature.
乔彤, 刘长红, 柳志刚, 蒙伟, 孙红. 载体平衡离子对MnOx/ZSM-5催化NH3-SCR性能影响[J]. 中国环境科学, 2021, 41(7): 3176-3183.
QIAO Tong, LIU Chang-hong, LIU Zhi-gang, MENG Wei, SUN Hong. The effect of equilibrium ion on the NH3-SCR performance of MnOx/ZSM-5catalysts. CHINA ENVIRONMENTAL SCIENCECE, 2021, 41(7): 3176-3183.
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