Catalysis Letters, Vol.79, No.1-4, 137-147, 2002
Catalytic conversion of N2O to N-2 over metal-based catalysts in the presence of hydrocarbons and oxygen
The catalytic conversion of N2O to N-2 in the presence or the absence of propene and oxygen was studied. The catalysts examined in this work were synthesized impregnating metals (Rh, Ru, Pd, Co, Cu, Fe, In) on different supports (Al2O3, SiO2, TiO2, ZrO2 and calcined hydrotalcite MgAl2(OH)(8).H2O). The experimental results varied both with the type of the active site and with the type of the support. Rh and Ru impregnated on gamma-alumina exhibited the highest activity. The performance of the above most promising catalysts was studied using various hydrocarbons (CH4, C3H6, C3H8) as reducing agents. These experimental results showed that the type of reducing agent does not affect the reaction yield. The temperature where complete conversion of N2O to N-2 was measured was independent of the reductant type. The activity of the most active catalysts was also measured in the presence of SO2 and H2O in the feed. A shift of the N2O conversion versus temperature curve to higher temperatures was observed when SO2 and H2O were added, separately or simultaneously, to the feed. The inhibition caused by SO2 was attributed to the formation of sulfates and that caused by water to the competitive chemisorption of H2O and N2O on the same active sites.