摘要
与传统NH_(3)-SCR不同,C_(3)H_(6)-SCR由于较高的反应能垒在低温下(<300℃)通常表现出较差的脱硝性能。在模拟实际发动机稀燃条件下,采用浸渍法制备了一系列Mn_(x)Zr_(y)La_(z)/ZSM-5非贵金属催化剂,在C_(3)H_(6)-SCR中表现出优异的低温脱硝性能,其NO转化率在空速为30000 h^(-1)温度区间为190~270℃超过90%,最高NO转化率在250℃达到100%。实验结果表明,La引入明显地提高了催化剂的孔道直径(3.20→4.07 nm),显著提升了活性Mn物种的分散以及活性Mn物种的表面离子浓度,进而增加催化剂表面Lewis酸数量;此外,XPS结果表明,La的引入产生了更多的Mn^(4+)向Mn^(3+)的电子转移,在活性物种MnO_(x)上造成更多的晶格氧空位,这些提升可能是Mn_(15)Zr_(3)La_(10)/ZSM-5催化剂表现出优异低温活性的原因。我们希望这项研究能有助于揭示稀土金属La在低温C_(3)H_(6)-SCR中的影响,并有助于进一步合成高活性的非贵金属低温C_(3)H_(6)-SCR催化剂。
Traditionally,C_(3)H_(6)-SCR exhibited poor catalytic activity at low temperature(≤300℃)due to the difficult activation of C_(3)H_(6).Under the simulated lean burn condition of actual diesel engines,100%NO conversion was obtained at 250℃and more than 90%NO conversion were observed at 190℃~270℃with the space velocity of 30000/h on the Mn_(15)Zr_(3)La_(10)/ZSM-5 catalyst prepared with co-impregnation method.The results showed that La doping significantly increased the pore diameter of the catalyst(3.20 nm→4.07 nm)and the dispersion of active species Mn,and further increased the sites of lewis on the surface of the catalyst).XPS results indicated that La doping resulted in more electron transfer from Mn^(4+) to Mn^(3+),and generated more lattice oxygen vacancies on the active species MnOx.All of this may be responsible for the excellent low temperature activity of Mn_(15)Zr_(3)La_(10)/ZSM-5 catalyst.We expect this study to shed revealing the effect of rare earth metal La in low temperature C_(3)H_(6)-SCR,and contributing to the further synthesis of highly active non-noble metal low temperature C_(3)H_(6)-SCR catalysts.
作者
唐田
许俊强
盛小红
张艳容
邹贤林
郭芳
张强
TANG Tian;XU Junqiang;SHENG Xiaohong;ZHANG Yanrong;ZOU Xianlin;GUO Fang;ZHANG Qiang(College of Chemistry and Chemical Engineering,Chongqing University of Technology,Chongqing 400054,China)
出处
《功能材料》
CAS
CSCD
北大核心
2022年第8期8140-8146,共7页
Journal of Functional Materials
基金
国家自然科学基金(21902017)。
