程序升温条件下铁及其氧化物在CO存在时对N_2O的还原机理

Reduction of N_2O in the presence of Fe and its oxides with CO at programmed temperature

应用热综合分析仪 (TG FTIR)研究了在还原性气氛下Fe及其氧化物对N2 O的催化还原作用 .研究发现铁氧化物对氮氧化物的催化还原能力相当弱 ,而Fe可以高效地降低N2 O分解的初始温度和提高N2 O向N2 的转化率 .在Fe和CO的作用下 ,N2 O的初始分解温度为 92 0K和 10 0 0K .在 112 3K时 ,N2 O的转化率达到 95 %和 80 % .TG/DSC曲线表明了在Fe与N2 O反应过程中CO的作用表现为通过与N2 O在反应表面的竞争吸附使铁氧化物还原为金属铁 ,X射线衍射证明Fe与N2 O反应后的氧化物为Fe2 O3 ;扫描电镜对反应后Fe表面物理形态的研究发现 ,在CO作用下 ,Fe的表面呈松散结构 。

Nitrous oxide(N 2O) is a greenhouse gas. With the development of fluidized bed combustion, the emission of the N 2O is generally observed. Chemical reactions between Fe and its oxides, N 2O and CO were investigated with TG\|FTIR. The oxides of iron were found to be relatively un\|reactive to the destruction of N 2O. The decomposition temperatures of N 2O were 1000K and 920K in the presence of Fe with/without CO, and the conversions of N 2O to N 2 at 1123K were 95% and 80%, respectively. TG/DSC curves confirmed that the most of iron oxides produced by Fe N 2O reaction could be reduced to metallic iron in the presence of CO. XRD pattern revealed that the N 2O reacted with iron to yield Fe 2O 3 as the major product. ESM showed that very porous structure was formed when N 2O reacted with Fe and CO. The results showed that Iron is a strong reducing agent for N 2O reduction.