SUPPORTED RHODIUM CATALYSTS FOR NITROUS-OXIDE DECOMPOSITION IN THE PRESENCE OF NO, CO2, SO2 AND CO

Nitrous oxide (N2O), a greenhouse gas and ozone destroyer, is a by-product of coal combustion in fluidized coal combustors (FBC's). We have examined the viability of using supported rhodium catalysts at various reaction temperatures to reduce nitrous oxide into nitrogen and oxygen in the presence of CO, NO, SO2, and CO2, which are also present in fossil fuel emissions. The rhodium catalyst was oxidized in a 20% O-2-80% N-2 mixture prior to each experimental trial. EDS studies suggest that rhodium concentrates near the catalyst surface following oxidation for 60 min. A space time of 0.07 min was sufficient to ensure 95% conversion of N2O into nitrogen and oxygen at 730 K. No statistically significant effects on N2O conversion were apparent when CO2 (15 volume-%), SO2 (1000 ppm), or NO (370 ppm) were added to the reactor feed streams. However, concentrations of CO as low as 0.4 volume-% lowered the temperature for 95% N2O conversion from 730 to 600 K.