Effect of CuMn2O4 spinel in Cu–Mn oxide catalysts on selective catalytic reduction of NOx with NH3 at low temperature

Identification of MnO species and Mn valence states in MnO /TiO2 catalysts for low temperature SCR

“…According to the previous studies, Fe [40,41], Cu [37,42], Ni [13,43], Co [42] and Cr [43] showed the favorable effect on the catalytic activity among the transition metals. For the quantitative chemical analysis, the end-point of titration could not be determined due to the disturbance from the combinations between the EDTA and transition metals.…”

“…In addition, by performing peak-fitting deconvolution, the Mn 2p 3/2 spectra could be separated into three peaks: 640.3-640.7, 641.8-642.0 and 643.2-644.5. These deconvoluted peaks corresponded to the Mn 2+ peak, Mn 3+ peak and Mn 4+ peak, respectively [36,37]. However, the results were not believable and scientific if the Mn 2p 3/2 peak of pure Mn 2 O 3 were separated into three peaks, assuming that Mn 2+ , Mn 3+ and Mn 4+ cations existed.…”

Selective Catalytic Reduction of NO over Cu-Mn/OMC Catalysts: Effect of Preparation Method

“…The acid properties of Cu-Mn/OMC samples were investigated because selective reduction of NO by NH 3 is significantly affected by the strength of acid sites on the surface of catalysts (Fang et al, 2014). The NH 3 -TPD profiles of three catalysts are shown in Fig.…”

“…For Cu 2p spectra, the two characteristic peaks at 932.4 eV and 934.6 eV were attributed to Cu + and Cu 2+ , respectively, by performing peak-fitting deconvolutions. Cu 2+ was considered to adsorb and activate NO molecules (Fang et al, 2014), and would favor NH 3 -SCR reaction by the redox cycle between Cu 2+ and Cu + . Given that the CuMn/OMC(S) had a significantly higher ratio of Mn 4+ /Mn 3+ and Cu 2+ /Cu + than Cu-Mn/OMC(I) or Cu-Mn/OMC(M), together with a stronger surface acidity and a larger amount of active oxygen owing to high content of O-C=O and chemisorbed O, the Cu-Mn/OMC(S) might exhibit the best catalytic performance in NH 3 -SCR reaction.…”

“…Kiani et al (2014) investigated the ratios of MnO2/OMC composite synthesized by impregnation method and found that the chemical properties were remarkably improved with the addition of MnO 2 . Moreover, Mn-based and Cu-based catalysts, such as MnO x /TiO 2 (Sultana et al, 2012), MnO x /CNTs (Su et al, 2013), CuMn 2 O 4 (Fang et al, 2014), CuO x /AC , exhibit relatively high SCR activities especially at low temperature. Therefore, a series of CuO x and MnO x containing OMC with different metal loadings were prepared for NH 3 -SCR of NO in our previous study (Cao et al, 2015), which illustrated that the catalyst with 5 wt.% Cu and 5 wt.% Mn exhibited the best catalytic performance.…”