Catalytic Reduction of NO with NH₃ over Carbons Impregnated with Cu and Fe

Abstract

Selective catalytic reduction (SCR) with NH3 remains as one of the most effective technologies controlling NOx emission from stationary sources. At low temperatures carbon exhibits higher catalytic activity in NOx reduction than conventional catalysts made of metal oxides or zeolites. In the present work, the rate of catalytic NO reduction conducted at 110-200 degrees C over mineral matter free carbon particles was found to be low, contrary to the findings reported in the literature. The activity of the carbon was significantly enhanced from impregnating it with nitrates of Cu and Fe. The carbon impregnated with Cu shows the highest activity. The affinity of these carbon catalysts toward NH3 and NO, as well as the tendency of the impregnated metal oxides toward reduction by carbon and H2, has an order identical to that of their activity in NO reduction. The high activity of the metal-loaded carbons was related to the combined catalytic effects of the carbon and the metal. It has been suggested on the basis of this study that the metal-carbon complexes may serve as the catalytic centers for oxygen transference from NO to NH3, which is essentially slow in the absence of the metal.

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

“…In the following sections, we will systematically summarize the recent research advances in understanding the structure-activity relationship of Fe-and Ce-based oxide catalysts in the NH 3 45 or activated carbon fiber (ACF) 46 etc. Yet at that time, no systematic studies of the microstructure of Fe species and its relationship with SCR performance were reported.…”

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

“…The contents of active phase in three samples were approximate to the theoretical value (5%), indicating little metal loss during catalyst preparation process. In addition, the population of oxygen in Cu-Mn/OMC(S) was much higher than that in catalysts prepared by the other two methods, which might be due to the oxidation of carbon support with in-situ addition of precursor acid radical during preparation and could lead to relatively high catalytic performance (Teng et al, 2001).…”

“…The content of C-O groups in Cu-Mn/OMC(S) was less than that in the other two samples, which might be caused by the transformation of C-O groups into O-C=O (Levi et al, 2015). As the carboxyl had the strongest acidity among fundamental groups (Teng et al, 2001), the increase of O-C=O might lead to a higher surface acidity and superior catalytic performance . The O 1s spectra were fitted into three peaks assigned to lattice oxygen in the metal oxides (530.6 eV), C-OH or C-O-C (532.2 eV), and chemisorbed O (533.3 eV), respectively (Biniak et al, 1997;Zafra et al, 2014).…”

Investigation of Catalyst Copper Supported on Ceramic Honeycomb Substrate for the SCR of NO

“…Transition metal Cu based catalysts had been investigated as a cheaper and efficient catalyst for the NOx removal in an SCR at a low temperature [10]. Cu-based catalysts have been investigated to improve SCR NOx conversion rate at a low temperature supported on different substrates, such as active carbons [11][12][13], zeolite [14][15][16][17][18], TiO 2 [19], Al 2 O 3 [20,21]. The use of these catalysts has shown an improvement of SCR activity to certain degree at a temperature below 250 °C under different conditions.…”