水滑石衍生CuMgFe-LDO催化剂协同净化氮氧化物和甲醇

Hydrotalcite-derived CuMgFe-LDO catalyst for simultaneous abatement of nitrogen oxides and methanol

NH_(3)-SCR催化剂同时去除NO_(x)和挥发性有机物(VOCs)引起了人们的广泛关注,然而,VOCs的存在会对脱硝反应产生负面影响,尤其在低温条件下。本研究选定水滑石衍生复合氧化物(Cu)MgFe-LDO催化剂探索协同脱除NO_(x)和甲醇性能,着重考察Cu的引入以及CuO_(x)和FeO_(x)相互作用对协同反应的影响,并对所制备的催化剂进行表征测试。结果表明,含Cu催化剂的脱硝活性均高于MgFe-LDO催化剂,最佳催化剂Cu_(0.5)MgFe-LDO在230~300℃温窗内具有较好的脱硝活性和甲醇氧化性能。适量引入Cu加强了Cu、Fe物种间的相互作用,有利于氧化还原循环,从而产生更多的氧缺陷及活性氧,过量Cu掺杂会破坏催化剂结构,降低表面酸性,引入Cu可以减缓甲醇对SCR反应的抑制作用。这些结果可为实际应用SCR催化剂协同去除VOCs提供指导。

The simultaneous abatement of NO_(x)and volatile organic compounds(VOCs)by NH_(3)-SCR catalysts has attracted lots of attention.However,the presence of VOCs can have negative impact on deNO_(x)efficiency especially at low temperatures.In this study,hydrotalcite-derived composite oxide(Cu)MgFe-LDO catalysts were selected to explore the simultaneous removal of NO_(x)and methanol,focusing on the introduction of Cu and the influence of CuO_(x)and FeO_(x)interaction on the synergistic reaction,and the prepared catalysts were characterized and tested.The results showed that the deNO_(x)activity of Cu-containing catalysts was higher than that of MgFe-LDO catalysts,and the optimal catalyst Cu_(0.5)MgFe-LDO exhibits the best catalytic activity for both NH_(3)-SCR and methanol oxidation in the temperature window of 230—300℃.The appropriate introduction of Cu strengthens the interaction between Cu and Fe species,which is conducive to the redox cycle,resulting in more oxygen defects and reactive oxygen species.Excessive Cu doping will destroy the catalyst structure and reduce the surface acidity.The introduction of Cu can slow down the inhibitory effect of methanol on the SCR reaction.These results can provide useful guidance for the practical application of SCR catalysts for synergistic removal of VOCs.