脉冲放电协同Ag改性CeO_x/γ-Al_2O_3催化剂对富氧条件下NO_x的脱除

Pulsed discharge coordinated with Ag modified CeO_x/γ-Al_2O_3 catalyst for NO_x removal under the oxygen rich atmosphere

随着机动车尾气中氮氧化物排放量的逐年增加,其对环境还有人体的危害也越来越大,为控制氮氧化物的排放,采用多针-板脉冲放电协同负载Ni、Co、Mn、Ce等金属氧物的复合型γ-Al_2O_3催化剂技术研究其在富氧条件下的脱硝效率,以及NO转化率,并使用Ag对γ-Al_2O_3催化剂进行相关改性制备出金属氧化物复合型催化剂,进而研究其脱硝率。结果表明:CeO_x/γ-Al_2O_3催化剂的催化效果好于其他金属氧化物催化剂,其中脉冲放电协同CeO_x/γ-Al_2O_3催化剂脱硝率为40.75%;不同负载量的Ce对催化剂活性影响也不同,协同负载量为1%的CeO_x/γ-Al_2O_3催化剂最佳脱硝效率为48.89%,NO转化率达到67.33%;在Ag改性且Ag负载量为1%后,CeO_x/γ-Al_2O_3催化剂其协同脉冲放电脱硝效率达到51.67%,对其BET表征后发现比表面积增加了3 m^2·g^(-1),同时催化剂上NO_x的还原活化位点增多。实验结果表明Ag改性CeO_x/γ-Al_2O_3催化剂协同脉冲放电在富氧条件下可以有效提高NO_x去除率,为下一步开发更高性能的催化剂提供了研究依据。

With the increasing of nitrogen oxides emissions from vehicle exhaust each year,more and more harmful effects occurred on the environment and human being.In order to control the nitrogen oxides emission,a type of multi-needle-plate pulse discharge method coordinated with the technology of y-AI203catalyst supported with metal (such as Ni,Co,Mn and Ce)oxides was used to study the denitrification and NO conversion under the condition of oxygen enrichments.A type of metal oxide composite catalyst was also prepared by modifying y-A1203with Ag. The results show that the CeOx/y-A1203catalyst has a better catalytic performance than other metal oxide catalysts, and the denitrification rate could reach 40.75%in coordination with the pulse discharge.The catalytic activity of CeOx/y-A1203catalyst depended on the loaded Ce content,and 1% Ce loading can result in the best denitrification rate of 48.89%for this catalyst with the NO conversion rate of 67.33%.For the CeOx/y-AI203catalyst modified with 1%Ag loading,its denitrification rate could reach 51.67%in coordination with the pulse discharge.The BET test for this catalyst showed that its specific surface area increased by 3m2.g^-1,and the activation sites on its surface for NOx reduction increased.We concluded that the Ag-modified CeOx/y-A1203catalyst in coordination with the pulse discharge can effectively improve the NOx removal rate under the condition of oxygen enrichment,which is helpful to further research on this type of catalyst with a high denitrification performance.