Sn基催化新材料用于致霾空气污染物消除

SnO2 materials with different morphologies and Sn-containing zeolites are potential catalytic materials for environment pollution control, but still lack systematical and deep investigation up to date. Based on the characteristics of the air pollutants causing haze, and aiming to solve the large area haze problem, which has frequently occurred in our country over recent years, two types of Sn-based catalytic materials are to be designed and prepared for the elimination of haze-causing pollutants, (1) SnO2 materials with different morphologies for the oxidation of carbon monoxide, hydrocarbons and soot particulate materials; (2) Sn-zeolites for NOx selective reduction. According to these objectives, effective methods for the preparation of efficient multi-morphologies SnO2 materials and Sn-containing zeolites will be explored systematically in this project. In addition, the bulk and surface properties of the prepared catalysts, such as crystalline and pore structures, preferentially exposed crystal facets, valence state distribution of the metals, microscopic electron structures and redox properties, are to be thoroughly characterized. Based on the provided information, the active sites of the catalysts and the reaction mechanisms will be clearly elucidated, with the expectation to provide guidance for purposefully designing applicable catalysts for removing haze-causing air pollutants. With the implementing of this project, it is expected to provide novel ideas and open new gates for the developing of catalysts to remove haze-causing air pollutants, and possibly achieve replacement non-noble metal catalysts having the catalytic properties of noble metals. This applicant has performed earlier stage and systematical research on using regular SnO2-based nano powders as catalysts for environmental pollution control reactions, which has laid a solid foundation for the accomplishment of the objectives proposed in this project.

多形貌氧化锡和含锡分子筛是具有潜在应用前景的环保催化剂，但迄今仍缺乏系统深入研究。针对国内大面积频发的雾霾问题及致霾污染物的特点，本项目拟设计制备两类锡基催化材料用于致霾污染物消除：（1）多形貌氧化锡用于一氧化碳，碳氢化合物和碳烟颗粒的氧化；（2）含锡分子筛用于氮氧化物的还原。针对上述目标，本项目将系统探讨制备高性能多形貌氧化锡和含锡分子筛催化剂的有效方法；深入研究不同催化剂的体相和表面性质，如晶相和孔道结构、优先暴露晶面、金属离子价态分布、微观电子结构和氧化还原性质等。明确指认反应中心，阐明反应机理，为有目的地设计具有实用价值的致霾污染物消除催化剂提供指导。本项目的实施可为发展致霾污染物消除催化剂提供新思路，开辟新途径，并有可能得到具有贵金属催化性能的非贵金属替代材料。申请人对常规纳米粉末氧化锡材料用作环保催化剂已进行过较系统的前期研究，为本项目的顺利实施奠定了坚实的基础。

本项目致力于研制消除不同致霾污染物的Sn基催化新材料，广泛探讨了催化剂的制备方法及其反应性能。利用各种物理化学手段探究了污染物消除反应的构效关系和机理；明确指认了Sn基催化材料表面活泼氧的状态，理清了决定反应性能的本质因素。重要结果总结如下：.（1）SnO2表面存在丰富的氧缺位，可解离吸附O2分子，诱导产生大量的表面活泼亲电氧。结果表明，超氧和过氧离子是其表面活泼氧的主要存在形式。改变SnO2形貌，或利用碱金属和一些过渡金属氧化物对其进行改性，可有效提高表面活泼氧中心的数量及其流动性，利于致霾污染物的消除。.（2）通过探讨SnO2为载体或负载物，与其它金属氧化物如TiO2，RuO2等作为负载物或载体时的相互分散行为，阐明了晶型对金属氧化物分散的影响。在国际上首次提出了“Like-Disperses-Like”的概念。.（3）Cu2+离子溶入SnO2纳米棒晶格形成固溶体，可有效提高了其比表面积和氧流动性。在相同条件下比1%Pd/SnO2具有更高的CO氧化活性。把CuO改性的SnO2基固溶体制备成三维有序大孔结构，可改善碳烟颗粒与活性中心的接触，形成更大量的表面活泼氧，从而大幅度提高催化剂的碳烟颗粒燃烧活性和选择性。.（4）Sn离子介入分子筛骨架，能有效抑制其在高温聚集；同时每个Sn离子可提供一个Lewis酸中心和氧化还原中心，利于反应物的吸附活化。其中Sn-MFI催化剂对NOx的选择还原具有良好的性能。.（5）利用少量金属离子改良SnO2纳米棒晶格形成固溶体时，可以促进生成更多的表面活泼氧和酸中心，促进一些VOCs分子的吸附和活化，提高其燃烧活性。.获授权发明专利5项。培养博士研究生3名，硕士研究生12名。发表第一标注 SCI 检索论文21篇，其中2篇为封面论文。先后14次受邀请在国内外学术会议上做主题报告和邀请报告。部分具有应用前景的催化剂与合作单位正在进行应用性能测试。.