Ag对Fe/Al-PILC的SCR-C3H6脱硝特性的影响  

Effect of Ag on deNOx performance of SCR-C3H6 over Fe/Al-PILC catalysts

作　　者：张显威 苏亚欣[1] 程江浩 林睿 温妮妮 邓文义[1] 周皞 ZHANG Xian-wei;SU Ya-xin;CHENG Jiang-hao;LIN Rui;WEN Ni-ni;DENG Wen-yi;ZHOU Hao(School of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;Changzhou Vocational Institute of Engineering,Changzhou 213164,China)

机构地区：[1]东华大学环境科学与工程学院,上海201620 [2]常州工程技术学院,江苏常州213164

出　　处：《燃料化学学报》2019年第11期1368-1378,I0006,共12页Journal of Fuel Chemistry and Technology

基　　金：上海市自然科学基金(19ZR1400700);江苏省自然科学基金(BK20181161);中央高校基本科研业务费(2232019D3-24)资助~~

摘　　要：为提高低温段(<300℃)铝柱撑蒙脱土负载铁基催化剂的脱硝效率,采用银离子对其进行修饰。通过超声浸渍法合成银-铁双金属催化剂,并于固定床反应器中评价催化剂性能。结果表明,Ag的引入显著改善了Fe/Al-PILC催化剂的低温催化活性。在250℃时,Ag-Fe/Al-PILC催化剂的NO转化率达到60%以上,高于Fe/Al-PILC催化剂20%的NO的转化率,其中,2.1Ag-Fe/Al-PILC在250℃时NO转化率达到82%,N2选择性达到100%。而且,引入银离子后的双金属催化剂保持了铁基催化剂较好的抗H2O和SO2性能。通过多种技术探究催化剂的微观结构和物理化学性质。根据N2吸附-脱附测试结果表明,双金属催化剂形成了稳定的整体结构,并具有较大的内比表面积。同时,XRD和UV-vis表征结果显示,在催化剂表面形成的银-铁固溶体、Ag+和Agn^δ+物种是影响其低温活性的关键因素。Ag-Fe/Al-PILC的低温活性与形成的银-铁固溶体有关,同时在催化剂表面形成的Ag+和Agn^δ+物种是影响其低温活性的关键因素。XPS结果表明,Ag和Fe之间存在电子转移,形成了双金属协同作用,改变了催化剂表面的银、铁成分含量及其价态。H2-TPR结果表明,Ag促使Fe/Al-PILC还原特征峰出现在低温区,提高了其低温还原性能。表面酸性的Py-FTIR分析结果表明,Ag-Fe/Al-PILC催化剂同时存在Lewis酸和Bronsted酸,且Ag提高了Bronsted酸的稳定性。Silver has been widely used to modify the iron-based catalyst supported on alumina pillared montmorillonite to enhance its activity at lower temperature(<300℃).Bimetallic Ag-Fe/Al-PILC(Pillared interlayer clay)was prepared by the ultrasonic impregnation method and performance was tested on a fixed bed reactor.And the experiment results showed that silver obviously improved the catalyst activity at a lower temperature.The NO conversion efficiency of Ag-Fe/Al-PILC at 250℃was 60%,which was higher than Fe/Al-PILC(20%).The maximum 82%NO conversion and 100%N 2 selectivity were obtained by 2.1Ag-Fe/Al-PILC at 250℃.Moreover,Ag-Fe/Al-PILC revealed better anti-hydrogen peroxide and anti-sulfur dioxide ability.The catalyst characterization was conducted by several techniques with respect to the microstructure and physicochemical properties.According to the effects of N 2-adsorption and desorption tests,Ag-Fe/Al-PILC formed a stable overall structure and had a large internal specific surface area.Besides,XRD and UV-vis proved that the Ag-Fe solid solution,Ag+and Agδ+n species formed on the surface of the catalyst are the key factors affecting its low-temperature activity.XPS results suggested that there was electron transfer between Ag and Fe,which formed a synergistic effect of bimetals and changed the content of Ag and Fe and their valence state on the catalyst surface.The findings of H 2-TPR indicated that the modification of Ag promoted the shift of the Fe/Al-PILC reduction peak toward low temperature,which boosted the low-temperature reduction capacity of the catalyst.The surface acidity analysis by Py-FTIR indicated that Lewis acid and Br nsted acid existed simultaneously and Ag enhanced the stability of Br nsted acid.

关 键 词：选择性催化还原 柱撑黏土 Ag-Fe/Al-PILC 

分 类 号：X511[环境科学与工程—环境工程]