Preparation Of Sm-modified Manganese (cerium) Titanium-based Catalyst And Its NH₃-SCR Performance

With the rapid development of the economic,NO_x emissions have increased dramatically,which has caused a series of problems for the environment and human health.Usually,NH₃-SCR selective catalytic reduction is considered to be a very effective method of eliminating NO_x.At present,although V₂O₅-WO₃?MoO₃?/TiO₂catalyst has been used in some fixed sources of de-NO_x,its own operating temperature window is narrow?300-400 ??,and the biological toxicity of Vanadium and the vulnerability to SO₂ at high temperature are still insufficient.So this weakness limited its large-scale application.Therefore,there is still a need to develop a non-aluminum-based catalyst with good performance of low-temperature de-NO_x to meet the current demand for fixed source de-NO_x.In this paper,the redox properties and surface properties of Sm-modified Mn or Ce catalysts are used to improve the catalytic activity of Mn or Ce-based catalysts and the ability of low-temperature NH₃-SCR to eliminate NO_x.Three series of catalysts of Sm_yMnTi₉O_x?y=0,0.1,0.2,0.3,0.4?,Sm_bCeTi₄O_x?b=0,0.1,0.2,0.3,0.4?and Sm_aMn Ni₂Ti₇O_x?a=0,0.1,0.2,0.3,0.4?were prepared by sol-gel method and co-precipitation method,respectively.In addition,the effects of Sm doping on its de-NO_x performance were discussed detailed,respectively.And the catalysts were characterized by XRD,H₂-TPR,NH₃-TPD,XPS,and DRIFTS.The activity test results show that Sm_0.3MnTi₉O_x,Sm_0.3Mn Ni₂Ti₇O_x and Sm_0.1CeTi₄O_xcatalysts have better low-temperature NH₃-SCR properties in their respective series of catalysts.Various characterization results show that the addition of Sm can improve the surface acidity and the specific surface area of the catalyst to modulate the redox of the catalyst,thereby broadening the active temperature window of the catalyst NH₃-SCR.The In situ diffuse reflectance infrared spectroscopy was used to study the NH₃-SCR de-NO_x mechanism of the catalyst.