掺Nb改性促进Mn-Cu/BCN催化剂低温SCR脱硝性能的机制研究  

Mechanism study on the enhancement of low-temperature SCR denitrification performance of Mn-Cu/BCN catalyst by Nb doping modification

作　　者：季科 钟金钦 刘冰冰 郭健翔[2] JI Ke;ZHONG Jinqin;LIU Bingbing;GUO Jianxiang(College of Architecture and Surveying and Mapping Engineering,Shanxi Datong University,Datong 037003,China;School of Environmental and Municipal Engineering,Qingdao University of Technology,Qingdao 266520,China)

机构地区：[1]山西大同大学建筑与测绘工程学院,山西大同037003 [2]青岛理工大学环境与市政工程学院,山东青岛266520

出　　处：《燃料化学学报(中英文)》2025年第4期538-554,共17页Journal of Fuel Chemistry and Technology

基　　金：国家重点研发计划(2020YFD1100302);山东重点研发计划(竞争性创新平台)(2022CXPT051)资助。

摘　　要：氨法选择性催化还原(NH_(3)-SCR)脱硝技术是目前应用最为广泛的脱除NO_(x)技术,技术核心是开发出具有廉价、高效、抗中毒性能强的催化剂。本研究针对现有商用催化剂处理低温烟气脱硝性能差、反应温窗窄、抗中毒性能差等问题,利用微波辅助浸渍法通过掺Nb改性制备了具有良好低温催化活性的Mn_(7)-Cu_(3)-Nb_(x)/BCN催化剂。NH_(3)-SCR测试结果表明,掺Nb量为0.05%的Mn_(7)-Cu_(3)-Nb_(0.05)/BCN催化剂表现出了最佳的SCR催化活性,该催化剂在150-275℃具有不低于94%的NO转化率,且N_(2)选择性也得到提升。抗水抗硫中毒实验结果表明,掺Nb改性催化剂Mn_(7)-Cu_(3)-Nb_(0.05)/BCN同样具有较好的抗中毒性能,在通入1.0×10^(-4)SO_(2)和5%H_(2)O 14.75 h后,其NO转化率仍能稳定维持在75%以上。结合SEM、XRD、XPS、NH_(3)-TPD、NO-TPD以及原位红外漫反射(in situ DRIFT)等多种表征手段详细探究了掺Nb改性对于Mn_(7)-Cu_(3)/BCN催化剂低温SCR脱硝性能的增强机制。结果表明,掺Nb改性能够有效抑制Mn_(7)-Cu_(3)/BCN催化剂表面上CuO和Cu物种的结晶,进一步促进了活性组分的均匀分散。同时,Nb的掺杂有效提升了Mn^(4+)和O_α物种浓度,促使更多的NO被氧化为NO_(2),促进了“Fast-SCR”反应进程。掺Nb改性能够促进NH_(3)和NO的吸附与活化,促使更多的-NH_(2)、硝酸盐等有益中间体加速形成,进而有效提升了SCR脱硝反应的整体反应速率。本研究为深入理解掺Nb改性的影响机制提供了重要的科学依据,并为低温烟气脱硝技术的发展提供了有益的探索和参考。With the rapid process of industrialization,the emission of nitrogen oxides(NO_(x))has become increasingly prominent and has become a key issue that urgently needs to be addressed in the field of environmental protection.The excessive emission of NO_(x)not only causes acid rain,exacerbates urban haze and other environmental problems,but also poses an undeniable threat to human health.Therefore,it is particularly important to develop and apply efficient NO_(x)reduction technologies,which have significant implications for improving air quality and protecting the ecological environment.Among numerous technologies,ammonia selective catalytic reduction(NH_(3)-SCR)technology is highly favored due to its excellent performance and practicality,and has become the most widely used NO_(x)removal technology at present.The core of this technology lies in the development of catalysts that are both cost-effective,highly effective,and possess strong anti poisoning properties.This study aims to address the problems of poor denitrification performance,narrow reaction temperature window,and poor anti poisoning performance of existing commercial catalysts for low-temperature flue gas treatment.A Mn_(7)-Cu_(3)-Nb_(x)/BCN catalyst with good low-temperature catalytic activity was prepared by microwave-assisted impregnation method through Nb doping modification.The NH_(3)-SCR test results showed that the Mn_(7)-Cu_(3)-Nb_(0.05)/BCN catalyst with a Nb content of 0.05%exhibited the best SCR catalytic activity.The catalyst had a NO conversion rate of not less than 94%in the temperature range of 150-275℃,and the N_(2)selectivity was also improved.The experimental results of anti water and anti sulfur poisoning showed that the Nb doped modified catalyst Mn_(7)-Cu_(3)-Nb_(0.05)/BCN also had good anti poisoning performance.After introducing 1.0×10^(-4)SO_(2)and 5%H_(2)O for 14.75 h,its NO conversion rate can still be stably maintained at over 75%.The enhancement mechanism of Nb doped modification on the low-temperature SCR denitrification p

关 键 词：低温脱硝 氨法选择性催化还原 Mn-Cu/BCN催化剂 掺Nb改性 

分 类 号：X511[环境科学与工程—环境工程]