The effect of CO₂, a major component of the exhaust gas, on the elimination of NO_x over FeW oxide catalyst was studied. It reveals that the presence of CO₂ inhibits NO_x conversion and N₂ selectivity, which is due to the triple interactions of carbonate-Fe₂O₃–FeWO₄. CO₂ could be adsorbed to form carbonate species. The electron interactions between carbonate species and FeW oxides decrease the electron cloud density of Fe and W, leading to the increment of electrophilicity of metal species and thereby promoting the formation of nitrates. Meanwhile, a new reaction mechanism is proposed in which the NO₂ species formed on the catalyst surface can react with the adsorbed NH₃ or NH₄⁺ by following the E–R mechanism. Meanwhile, NO₃⁻ could combine with NH₄⁺ to form the NH₄NO₃ intermediate, which disciplines the L–H mechanism.

中文翻译：

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揭示CO2对FeW混合氧化物催化剂上NH3催化NOx的影响机制

研究了废气的另一种主要成分 CO2 对 FeW 氧化物催化剂消除 NOx 的影响。结果表明，CO2 的存在会抑制 NOx 转化和 N2 选择性，这是由于碳酸盐-Fe2O3-FeWO4 的三重相互作用所致。 CO2 可以被吸附形成碳酸盐物质。碳酸盐物质和FeW氧化物之间的电子相互作用降低了Fe和W的电子云密度，导致金属物质的亲电性增加，从而促进硝酸盐的形成。同时，提出了一种新的反应机理，催化剂表面形成的NO2物种可以通过以下ER机理与吸附的NH3或NH4+反应。同时，NO3-可以与NH4+结合形成中间体NH4NO3，从而调节LH机制。