Improvements in NOx reduction by carbon using bimetallic catalysts

The catalysis of the C-NOx reaction has been studied to optimize the compos ition of the catalysts in order to decrease the carbon consumption by oxyge n. Both the metal content and the composition of the catalysts have been in vestigated. The activity of bimetallic (KNi, NiCo and NiCu) catalysts for N Ox reduction by carbon has been studied using both isothermal reactions at 300 degreesC and temperature programmed reaction up to 500 degreesC. It has been found that the experimental variables (i.e. amount of catalysts and n ature of the bimetallic catalysts) determine the selectivity against carbon combustion by oxygen. Thus, it has been observed that the amount of cataly st greatly affects the C-O-2 reaction but only lightly the C-NOx reaction a nd, consequently, modifies the selectivity of the catalyst for NOx reductio n. Among the bimetallic catalysts tested, NiCu catalyst presents the best p erformance, at a temperature as low as 250 degreesC, a high de-NOx activity and a high NOx selectivity due to a low carbon burn-off, with the addition al advantage of the absence of N2O and CO in the reaction products. Thus, t he results obtained in this study show, in comparison with our previous res ults, that better selectivities are achieved. (C) 2001 Elsevier Science Ltd . All rights reserved.