低温等离子体协同吸附-分解NOx机理研究及催化剂的结构设计与优化

As one of the major air pollutants, nitrogen oxide (NOx) has a devastating effect on environment and human health. Therefore, it is extremely urgent to develop a novel and efficient de-NOx strategy. Catalyst is the core of the de-NOx technology. In order to design a catalyst with high activity and stability, the activity sites for NOx removal in a catalyst and the factors which can influence the formation of these sites should be deeply understood. In this project, the study was mainly to focus on the preparation of catalyst with good adsorption-decomposition NOx performance in a combined adsorption-low-temperature discharge plasma （NTP）catalytic process. Copper species were introduced into ZSM-5 and ZSM-11 zeolites with the similar composition via an ion exchange method, respectively. The formation and distribution of active sites in the zeolite channels were analyzed by comparing the adsorption-decomposition activity and texture properties of Cu-ZSM-5 and Cu-ZSM-11. The factors that affecting the formation and distribution of active sites were investigated by choosing parent zeolites with various pore structures and external surface areas. The oxygen-trap sites were revealed by investigating the oxygen-tolerant capacity of catalysts modified with rare earth element. Zeolites with different Si/Al ratios were chosen as support to display the water resistant capacity of catalysts. On the basis of the above work, a direct synthesis method would be applied to prepare the catalyst with a superior resisted oxygen and water capability as well as high adsorption-decomposition performance in a combined adsorption-discharge plasma catalytic decomposition process of nitrogen oxides.

氮氧化物（NOx）作为大气主要污染物之一，严重危害环境和人类身体健康，对其治迫在眉睫。催化剂是脱硝工艺的核心，设计高活性、高稳定性的脱硝催化剂的前提就是深入认识催化剂上NOx脱除活性位的形成及其影响因素。本项目主要进行吸附-低温等离子体（NTP）协同催化分解NOx的反应体系中高性能催化剂的制备研究。向具有相似性质的ZSM-5和ZSM-11分子筛中通过离子交换引入铜物种，对比研究其吸附分解活性以及结构性质，分析活性位的存在形式以及分布；通过改变载体分子筛的孔结构以及外表面明确活性位形成以及分布的影响因素；通过对稀土改性催化剂的抗氧性研究来揭示储氧活性位的结构和性质；通过对不同硅铝比载体负载活性组分后抗水性的研究来揭示催化剂抗水性能的原理。在上述工作的基础上，采用直接合成法一步制备出具有抗氧疏水性的高活性和稳定性的NOx吸附-NTP分解催化剂。

氮氧化物（NOx）作为大气主要污染物之一，严重危害环境和人类身体健康，对其治理迫在.眉睫。催化剂是脱硝工艺的核心，设计高活性、高稳定性的脱硝催化剂的前提就是深入认识催化剂上NOx脱除活性位的形成及其影响因素。本项目主要进行吸附-低温等离子体（NTP）协同催化分解NOx的反应体系中高性能催化剂的制备研究。考察几种不同类型的商用分子筛，确定了分子筛结构、性质、预处理方式以及制备方式对其吸附-NTP分解NOx活性的影响。向合成原料中添加金属离子，通过调整体系的性质以及晶化条件一步合成得到了含有金属的ZSM-11分子筛。将ZSM-11应用于NO吸附-分解，考察了Na型/H型、硅铝比对HZSM-11吸附-NTP催化分解NOx性能的影响。研究了制备方法、前驱体、对Cu-ZSM-11吸附-NTP催化分解NOx性能的影响，同时考察了Cu-ZSM-11催化热分解以及吸附-热解脱除NOx性能，并对ZSM-5进行对比，结果发现，ZSM-11应用于该体系时所表现出的性能逊于ZSM-5。鉴于此，调整后期研究内容，着重对H-ZSM-5应用于NO的吸附-NTP催化分解体系中时NOx吸附-NTP分解工艺流程进行调控。考察了几种不同工艺流程对NOx吸附-分解性能的影响，筛选出最佳工艺流程。此外，考察了不同含水量、材料疏水改性和分离系统对分子筛吸附/催化分解NO的影响，并通过优化工艺过程，提高了催化剂的寿命。该项目的进行不仅为分子筛在NOx吸附-NTP分解脱除工艺过程中的应用提供了理论认识和基础，而且对其未来的实际应用具有重要的理论指导意义。