Study of the temperature window for the selective reduction of NOx in O2-rich gas mixtures by metal-loaded carbon

The selectivity of different catalysts towards NOx reduction by carbon against O2 combustion has been studied. It allowed concluding that selective catalysts are those that showed carbon conversion onset temperature about 400 °C, potassium being the most promising candidate among the catalysts studied. Catalysts that were very active below 400 °C such as copper and rubidium were not selective for NOx reduction and neither those catalysts that only reacted well above 400 °C, such as calcium, iron, cobalt, nickel, cerium and zirconium. In addition, most catalysts studied favoured CO2 formation as reaction product with regard to CO, alkali metals being the most effective.