Low temperature selective catalytic reduction of NOX with NH3 by activated coke loaded with FexCoyCezOm: The enhanced activity, mechanism and kinetics

A Review of Low Temperature NH3-SCR for Removal of NOx

“…The superior performance of the catalyst was ascribed to the co-participation of Fe, Co, and Ce species with different valence states, high concentration of chemisorbed oxygen, well dispersed active components, increase of weak acid sites, good redox properties of metallic oxides, and abundant functional groups on the catalyst surface. Their mechanistic and kinetic studies also indicated that the enhanced active sites for the adsorption Lu group [148] synthesized a series of activated coke (AC) supported Fe x Co y Ce z O m catalysts for low-temperature NH 3 -SCR, and found that the 3%Fe 0.6 Co 0.2 Ce 0.2 O 1.57 /AC catalyst had the best activity at 250-350 • C and good tolerance to H 2 O/SO 2 at 250 • C. The superior performance of the catalyst was ascribed to the co-participation of Fe, Co, and Ce species with different valence states, high concentration of chemisorbed oxygen, well dispersed active components, increase of weak acid sites, good redox properties of metallic oxides, and abundant functional groups on the catalyst surface. Their mechanistic and kinetic studies also indicated that the enhanced active sites for the adsorption of NO and NH 3 , and the redox cycle among Fe, Co and Ce were responsible for the improved activity.…”

“…Although the Mn0.4Ce0.07Ho0.1/TiO2 showed higher resistance to SO2 and H2O than the Mn0.4Ce0.07/TiO2 catalyst, it was deactivated some extent in presence of SO2/H2O which is irreversible. Lu group [148] synthesized a series of activated coke (AC) supported FexCoyCezOm catalysts for low-temperature NH3-SCR, and found that the 3%Fe0.6Co0.2Ce0.2O1.57/AC catalyst had the best activity at 250-350 °C and good tolerance to H2O/SO2 at 250 °C. The superior performance of the catalyst was ascribed to the co-participation of Fe, Co, and Ce species with different valence states, high concentration of chemisorbed oxygen, well dispersed active components, increase of weak acid sites, good redox properties of metallic oxides, and abundant functional groups on the catalyst surface.…”

Manganese oxides supported on ACFN by a one‐step redox method for the low‐temperature NOx reduction with NH3: effect of acid addition

“…It can be seen that the proportion of O β is the largest among all catalysts, which indicates that chemisorbed oxygen is the main active oxygen species on the surface of the catalyst. The chemisorbed oxygen has high mobility and facilitates the oxidation of NO to NO 2 in the NH 3 ‐SCR reaction at low temperature, leading to the improvement of the ‘fast‐SCR’ reaction . In addition, the surface of the MnO 2 /ACF N (CH 3 COOH) catalyst had a higher lattice oxygen content as compared to other catalysts, which suggested that there were more Mn‐O‐Mn species.…”

“…(b), the O 1s XPS spectra of all MnO 2 /ACF N catalysts can be resolved into three peaks. According to the relevant literature, the high binding energy peak around 533.1~533.2 eV is associated with adsorbed molecular water (O γ ), which also could be represented as H‐O‐H groups; the peak at 531.3~531.6 eV is caused by chemisorbed oxygen or weakly bonded oxygen species (O β ) (i.e. Mn‐O‐H groups) and the binding energy peak at 529.8~529.9 eV is assigned to lattice oxygen (O α ) or Mn‐O‐Mn groups.…”

“…The chemisorbed oxygen has high mobility and facilitates the oxidation of NO to NO 2 in the NH 3 -SCR reaction at low temperature, leading to the improvement of the 'fast-SCR' reaction. 24,26 In addition, the surface of the MnO 2 /ACF N (CH 3 COOH) catalyst had a higher lattice oxygen content as compared to other catalysts, which suggested that there were more Mn-O-Mn species. Figure 5(c) shows the C 1s XPS spectra of samples, which also can be divided into three peaks.…”