Study On Fabrication Of CuAl-based Mixed Oxides Catalysts With Strong SO₂ Resistance And Its Performance Promotion Mechanism

NH₃-SCR（Selective catalytic reduction with NH₃）,has been widely used for flues gas denitration at the present stage due to its advantages of the high removed efficiency,large gas treatment capacity and easy control of reaction conditions.The previous research of our group has confirmed that Cu Al composite oxides（Cu_yAl O_x）catalysts displayed better de NO_xperformance in NH₃-SCR,but the SO₂resistance was still poor.Therefore,it is of great significance to research and develop Cu Al-based oxides catalysts with enhancing SO₂resistance and take the better de NO_xperformance into account.This paper based on the better de NO_xperformance of Cu Al composite oxides catalysts,introducing the synergistic function component M and carbon nanotubes（CNTs）into Cu Al-based catalysts to promote the SO₂resistance.Besides,a series of characterization technologies（such as TG,XRD,BET,TEM,SEM,XPS,NH₃-TPD,SO₂-TPD,H₂-TPR,In-situ DRIFTs,TPDC,TPSR,etc）were employed to investigate the acid sites,redox,surface structure and adsorption capacity of NO_x/SO_xfor catalysts,and research the intrinsic connection of physicochemical property with denitrification performance,which might provide theoretical basis on preparing Cu Al-based mixed catalysts with high NO_xconversion and strong SO₂resistance.The main research contents and conclusions are as follows:（1）The effect of different assembly methods of Cu and Al on the de NO_xperformance were investigated,the results showed that Cu Al-LDO catalyst prepared by calcining Cu Al-LDH precursor possessed better performance than traditional impregnated Cu O_x/Al₂O₃.Based on this,the synergistic function component M（Co,Ni,Mg）were introduced into the layer of Cu Al-LDH,than Cu Co Al-LDO,Cu Ni Al-LDO and Cu Mg Al-LDO catalysts were obtained by calcining Cu MAl-LDH.The results displayed that doping Mg can enhance the NO_xconversion（the NO_xconversion above 80%within 195-285°C）simultaneously promote the SO₂resistance obviously（at 210°C,adding 100 ppm SO₂leading to 16.8%decreased value of NO_xconversion for Cu Mg Al-LDO within 16 h）.（2）CuAl-LDO,CuMg Al-LDO and CuO_x/Mg Al-LDO catalysts were fabricated to explore the effect of introduction Mg and introducing methods to surface structure,physicochemical property and de NO_xperformance,reveal the mechanism of enhanced SO₂resistance for Cu Mg Al-LDO catalyst.Meanwhile,the performance test demonstrated that introducing Mg improved the SO₂resistance for catalyst,but only Mg was existed on the layer as functional component can it play the role at the greatest extent.It was clearly revealed that introducing Mg into Cu Al mixed oxides catalysts by means of LDH achieved better de NO_xperformance.（3）CuMg Al-LDO/CNTs catalyst was prepared by in-situ assembling CNTs and Cu Mg Al-LDH follow with calcining,the mechanism of introducing CNTs on enhanced SO₂resistance was researched.The results indicated T₉₀for Cu Mg Al-LDO/CNTs was 190-290°C,which was obviously hihg than Cu Mg Al-LDO.Besides,adding 100 ppm SO₂leading to 7.2%decreased value of NO_xconversion for Cu Mg Al-LDO/CNTs,illustrating the introduction of CNTs further strengthen the SO₂resistanc for Cu Al-based catalyst,thus successfully preparing Cu Mg Al-LDO/CNTs catalyst with high NO_xconversion and strong SO₂ resistance.