Low-temperature NH3-SCR activity of M (M = Zr, Ni and Co) doped MnO supported biochar catalysts

• DOI: 10.1016/j.jece.2021.106504
• Publication Date: 2021-10-06T01:01:43Z
• Authors: Lin Chen; Shan Ren; Weizao Liu; Jie Yang; Zhichao Chen; Mingming Wang; Qingcai Liu
• Keywords: Selective catalytic reduction

Abstract Several metal (Zr, Ni and Co) oxides doped biochar (BC) supported Mn oxide (MnOx) catalysts were prepared by impregnation method, and their effects on the low-temperature selective catalytic reduction with NH3 (LT NH3-SCR) activity were studied. Zr-Mn/BC catalyst exhibited the highest NO conversion of around 87% at 200 oC and the best N2 selectivity of the four catalysts. Furthermore, Zr-Mn/BC catalyst showed better resistance of SO2 and H2O than that of Mn/BC catalyst. Metal oxides were evenly distributed on the surface of the four catalysts. Zr-Mn/BC catalyst, Ni-Mn/BC catalyst and Co-Mn/BC catalyst had lower surface area compared with Mn/BC catalyst. Moreover, the high activity of Zr-Mn/BC catalyst was related to its higher concentration of Mn4+, more surface oxygen (Oα), excellent redox property and more Lewis acid sites and Bronsted acid sites. From in situ DRIFTS, the Zr-Mn/BC catalyst followed Langmuir-Hinshelwood (L-H) reaction mechanism: the NH4+ species or NH3,ads reacted with the NxOy species (NO2,ads, NO2-, NO3-), finally generated N2 and H2O. In which the Zr doping could avoid the formation of N2O by restraining the decomposition of NH4NO3 intermediate.