Catalytic reduction of N<sub>2sub>O over steam-activated FeZSM-5 zeolite: Comparison of CH<sub>4sub>, CO, and their mixtures as reductants with or without excess O<sub>2sub>
- 作者：M.N. Debbagh ; C. Salinas Martí ; nez de Lecea ; J. Pé ; rez-Ramí ; rez
- 关键词：FeZSM-5 ; N<sub>2sub>O ; Decomposition ; Reduction ; SCR ; CH<sub>4sub> ; CO ; O<sub>2sub> ; Tail-gases
- 刊名：Applied Catalysis B ; Environmental
- 出版年：2007
- 期刊代码：4_09263373
- 类别：ce
- 出版时间：31 January 2007
- 卷：70
- 期：1-4
- 页码：335-341
- 文件大小：755 K
摘要
The catalytic reduction of N<sub>2sub>O by CH<sub>4sub>, CO, and their mixtures has been comparatively investigated over steam-activated FeZSM-5 zeolite. The influence of the molar feed ratio between N<sub>2sub>O and the reducing agents, the gas-hourly space velocity, and the presence of O<sub>2sub> on the catalytic performance were studied in the temperature range of 475–850 K. The CH<sub>4sub> is more efficient than CO for N<sub>2sub>O reduction, achieving the same degree of conversion at significantly lower temperatures. The apparent activation energy for N<sub>2sub>O reduction by CH<sub>4sub> was very similar to that of direct N<sub>2sub>O decomposition (140 kJ mol<sup>−1sup>), being much lower for the N<sub>2sub>O reduction by CO (60 kJ mol<sup>−1sup>). This suggests that the reactions have a markedly different mechanism. Addition of CO using equimolar mixtures in the ternary N<sub>2sub>O + CH<sub>4sub> + CO system did not affect the N<sub>2sub>O conversion with respect to the binary N<sub>2sub>O + CH<sub>4sub> system, indicating that CO does not interfere in the low-temperature reduction of N<sub>2sub>O by CH<sub>4sub>. In the ternary system, CO contributed to N<sub>2sub>O reduction when methane was the limiting reactant. The conversion and selectivity of the reactions of N<sub>2sub>O with CH<sub>4sub>, CO, and their mixtures were not altered upon adding excess O<sub>2sub> in the feed.