【摘要】 采用浸渍法、溶胶-凝胶法等不同途径制备了几种具有吸附分解NOx功能的多酸催化新体系,对其进行了IR、XRD表征,在固定床催化反应器中考察了体系对NOx的吸附与分解性能。结果表明:磷钨酸与SiO2之间有较强的相互作用,催化剂的分散形态与负载量密切相关;负载型催化剂对NO2均有较好的吸附能力,其中Fe(Ⅲ)USY载体对体系有明显的增效作用;不同方法制备的负载型磷钨酸对NO2的吸附性能相近;钨系杂多化合物性能优于钼系,Keggin结构的活性优于Dawson结构;磷钨酸与磷钼酸具有复配增效作用;随着磷钨酸负载量的增加,体系对NO2的吸附能力显著提高,最高吸附率达90%;适宜的吸附温度和气速分别为180~200℃和0.1~0.2 L/min。通过IR分析揭示了吸附质与催化剂的作用方式,通过GC-MS检测确认了吸附质催化分解为N2的有效性。更多还原

【Abstract】 Several new catalyst systems of heteropoly compounds with sorption-decomposition function for NO_x conversion were prepared by means of sol-gel,impregnation,physical blending and chemical synthesis.Subsequent to the IR and XRD characterization,the catalyst systems were evaluated using a fixed-bed catalytic reactor.The results showed that a strong interaction existed between H₃PW₁₂O₄₀ and the silica support,and the dispersion and morphological structure of catalyst on the support depended considerably on the amount of loading.The supported heteropoly compounds were found to be effective for NO₂ adsorption,and Fe（Ⅲ）USY was confirmed to be a favourable support having a promotive effect on the adsorption of NO₂.The H₃PW₁₂O₄₀/SiO₂ catalysts prepared by different methods were found to have nearly same capability on the adsorption for NO₂.Among the heteropoly compounds evaluated for NO₂ adsorption,H₃PW₁₂O₄₀ was superior to H₃PMo₁₂O₄₀,the P-W heteropoly compound with a Keggin structure showed better performance than that with a Dawson structure,the uniform mixture of H₃PW₁₂O₄₀ and H₃PMo₁₂O₄₀ is superior to either of its component.With the increase of the amount of catalyst loaded,the NO₂ adsorption efficiency of H₃PW₁₂O₄₀/SiO₂ increased markedly,achieving a top efficiency of 90%.The favourable temperature and gas velocity was at 180～200 ℃ and 0.1～0.2 L/min,respectively.With the aid of IR and GC-MC analyses,the NO₂-catalyst interaction mode and the process effectiveness for NO_x conversion to N₂ were revealed.更多还原