双功能滤料催化界面的构筑及其调控除尘脱硝机制

Catalytic filters (bifunctional filters) are low cost and high efficiency for synergistic removal of NOx and particulates, which have become the development direction of air pollution control technology in cement and steel industries. The key technology of bifunctional filters is the construction of catalytic interface. Different morphology and structure of the catalytic interface have significantly affected the removal efficiency for NOx and particulates of bifunctional filters and bonding strength of interface. However, its mechanism of affect action is still lack of systematic and mechanistic exploration, which restrict the further development and application of bifunctional filters. This project is will focus on the affect mechanism of the morphology and structure of the catalytic interface on the performance of the bifunctional filter. The construction of catalytic interface of bifunctional filter and the structure-activity relationship between its morphology and performance for removal of NOx and particulates will be studied systematically. Moreover, regulatory mechanism of catalytic interface on synergetic removal of NOx and particulates will be analyzed and the affect basis of the impact on the bonding strength of catalytic interface will also be revealed. Meanwhile, the influence of operating conditions on performance of synergetic removal of NOx and particulates over bifunctional filter will be studied systematically in this project, so that to achieve the mechanism of influence and further optimize the catalytic interface. It will not only provide innovative ideas for the design of bifunctional filters with excellent performance (NO removal efficiency > 90%, PM2.5 removal efficiency > 99.5%, Peel strength >15 N/50mm), but also provide theoretical basis for the final industrial application of bifunctional filter through the research of this project.

除尘脱硝双功能滤料成本低、效率高，成为水泥、钢铁等行业大气污染治理技术的发展方向，其技术关键是滤料功能催化界面的构筑。不同结构与形貌的催化界面会显著影响双功能滤料的除尘脱硝性能及其界面结合强度，但其作用机制目前仍缺乏系统性探究，成为制约该技术发展与应用的瓶颈。本项目以催化界面的结构形貌对双功能滤料性能的影响作用机制为切入点，重点研究双功能滤料催化界面的构筑及其结构形貌与除尘脱硝性能间的构效关系，解析催化界面对除尘脱硝性能的调控机制，揭示影响催化界面结合强度的本质；同时系统研究工况条件对双功能滤料除尘脱硝性能的影响，阐明影响作用机制并进一步调控优化催化界面。为设计性能优异（脱硝率＞90%、PM2.5脱除率＞99%）、催化界面结合强度高（剥离强度＞15 N/50mm）、普适性强的双功能滤料提供新思路，为双功能滤料的工业化应用提供理论支撑。

除尘脱硝双功能滤料成本低、效率高，成为水泥、钢铁等行业大气污染治理技术的发展方向，其技术关键是滤料功能催化界面的构筑。不同结构与形貌的催化界面会显著影响双功能滤料的除尘脱硝性能，但其作用机制目前仍缺乏系统性探究，成为制约该技术发展与应用的瓶颈。本项目以催化界面的结构形貌对双功能滤料性能的影响作用机制为切入点，重点研究双功能滤料催化界面的构筑及其结构形貌与除尘脱硝性能间的构效关系，解析催化界面对除尘脱硝性能的调控机制，揭示影响催化界面结合强度的本质；同时系统研究工况条件对双功能滤料除尘脱硝性能的影响，阐明影响作用机制并进一步调控优化催化界面。. 项目研究结果表明，球形催化界面为MnCeOx/P84双功能滤料的最佳催化界面，其在100-190 ℃时，脱硝率≥94%，连续240h测试后保持稳定性，界面剥离强度为20.55 N/50mm。粉尘和PM2.5脱除率均大于99.99%，满足商用除尘滤料标准。进一步研究催化界面的构效关系表明，弱结晶或无定形态的MnOx具有较弱的NH3氧化能力，从而抑制了N2O的生成，可提高低温脱硝活性与N2选择性；中孔通道可为脱硝反应提供适宜的通道，从而增强双功能滤料的选择性与脱硝性能；球形催化界面结构拓宽了双功能滤料的氧化还原窗口，提供了丰富的酸位及更多的活性位点；该结构还可提高双功能滤料中Oα/Oα+Oβ原子比例，提升吸附氧（Oα）、氧空穴数量与Mn4+浓度。工况条件下，当NH3/NO摩尔比＜1，氧含量＜6%时，双功能滤料的脱硝活性随NH3/NO摩尔比和氧含量的增加而快速增加。SO2存在会使双功能滤料脱硝活性下降至80%。通过优化球形催化界面双功能滤料的制备条件可使双功能滤料在130-160℃区间内脱硝率可达100%。同时，通过构筑TiO2包裹核壳结构催化界面可有效提高球形催化界面双功能滤料的抗SO2中毒性能，160℃通入SO2时，其脱硝率仍达到94%。