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Keywords:

  • NO oxidation;
  • Co3O4;
  • N2O generation;
  • NO2 formation;
  • hydrocarbon

Abstract

The catalytic activity of Co3O4 catalyst was examined in a differential reactor for converting NO to NO2 and N2O. It was observed that mostly NO was oxidized to NO2 rather than N2O over the catalyst at temperatures above 250°C in the presence of 5% oxygen and 10% water. The maximum conversion was 71% at 300°C. However, the presence of H2O slightly suppressed NO2 generation due to the occupation of active sites by H2O but no such effect was observed during N2O generation. At calcination temperature of 300°C, the maximum activity of the catalyst for NO conversion was observed due to the sintering of the catalyst at higher temperatures. In the presence of hydrocarbon, inhibition of NO conversion was also observed. This was due to the hydrocarbon competition with NO for the active sites of the catalyst. Moreover, on comparing with other workers, the activity of NO conversion over Co3O4 catalyst was found to be more selective towards NO2 generation at a wide range of temperatures resulting in less N2O generation. The activation energy (Ea) and pre-exponential factor (Ao) values were found to be 37.7 kJ mol−1 and −7.26 ppm−2 s−1. © 2011 American Institute of Chemical Engineers Environ Prog, 2011