磁旋滑动弧空气等离子体耦合催化固氮的机理研究

As the state-of the art technology for artificial nitrogen fixation, the success of Haber-Bosch process and its significant role in the development of global agriculture and industry are remarkable. However, the inherent disadvantages of this technology such as sophisticated facilities, enormous energy consumption and severe environmental pollution, limit its further development. In the present project, magnetic driven rotating gliding arc air plasma coupled with catalysis is innovatively proposed. Benefiting from its promising compatibility with the electricity from the intermittent renewable energy sources, the proposed technology is anticipated as an alternative green technology to realize the distributed and sustainable nitrogen fixation. Based on a systematical investigation of the physical characteristics of air plasma and corresponding influential factors, the intrinsic relationships between plasma properties and the efficiency of nitrogen fixation will be explored. A combined experiments and density-functional theory study will be conducted to reveal the mutual interaction between air plasma and prepared catalysts, the surface reaction mechanism and the synergistic principals of nitrogen fixation at a microscale level, in order to further optimize parameters and improve the efficiency of nitrogen fixation. Additional investigation of waste-derived defect-rich catalysts will be characterized and applied for nitrogen fixation. Eventually, the kinetic model and multi-physical coupling model of rotating gliding arc air plasma coupled with catalysis will be developed at a macroscale level. Based on the understanding of systematical reaction paths, parametric contribution rate and coupling principals of multi-physical fields, the reaction mechanism of magnetic driven rotating gliding arc air plasma coupled with catalysis will be revealed. The achievement of this project will provide a firm theoretical support for development of an economical, convenient and clean nitrogen fixation by plasma catalysis.

当前主流的人工固氮技术-哈柏法，对全球工农业的发展贡献显著，但其因系统设施复杂、能源消耗巨大和环境污染严重等缺点而饱受争议。本项目创新性地提出磁旋滑动弧空气等离子耦合催化技术，凭借其与间歇性可再生能源发电系统的良好兼容特性，实现分布式、可持续的绿色固氮。基于等离子物理特性及影响因素的系统研究，获悉等离子特性与固氮效率的内在联系；结合实验测试和密度泛函分析，从微观层面揭示等离子与催化剂间的互相作用规律、界面反应机理及协同固氮机制，从而优化参数，提升固氮效率；并拓展研究制备基于废弃物转化的缺陷结构催化剂及其在固氮中应用；从宏观尺度构建磁旋滑动弧空气等离子耦合催化固氮的反应动力学模型和多物理场耦合模型，掌握等离子催化固氮的系统反应路径、参数贡献权重及各物理场间的耦合机制，揭示磁旋滑动弧空气等离子耦合催化固氮的反应机理。研究成果将为推进经济、便捷的清洁等离子催化固氮应用提供理论基础。

为解决化石燃料驱动的合成氨固氮工艺的高耗能、高CO2排放等问题，本项目创新性提出了旋转滑动弧空气等离子体耦合催化技术，具有高反应活性（振动激发）/选择性、良好可再生电能兼容性和相对较大处理量等特点。.本项目工作为期三年，按照研究计划主要开展的工作有：建立起了适应于高效空气氧化/催化固氮的滑动弧反应系统；研究掌握了不同旋转等离子反应器结构和运行参数调控的伏安特性、光谱特性和动态特性；结合神经网络模拟，开展了空气固氮产物分析测试，在氧气浓度20～40%条件下，氧化固氮获得的NOx浓度高达15000ppm，能量效率约5.24MJ/mol，并揭示了气流量和氧气浓度分别对NOx浓度和能效的影响权重最大；进行了低温等离子体耦合催化固氮研究，开展不同金属/金属氧化物的系统表征、配比优化和催化固氮产物分析，发现MoO3/Al2O3复合催化可将固氮的性能提升40%；基于密度泛函理论，计算固氮产物NO和NO2路径和决速步能量势垒，并揭示等离子体作用下MoO3界面催化机制。结合光谱诊断、V-I特性分析和产物分布等，建立流场、电磁场和化学反应等的多物理场耦合模拟及优化验证，为后续实验优化提供了理论支持。.基于上述研究，主要创新性成果体现在：设计并优化旋转滑动弧反应装置的空气固氮系统，实现了高NOx浓度和能量效率的催化氧化固氮，揭示了调控参数对等离子体固氮物理特性和反应活性的影响机制；优化低温等离子体与催化剂耦合，实现了气-液两相固氮性能的大幅提升；结合先进光谱诊断和多尺度模拟（DFT和多物理场耦合模拟等），掌握了低温等离子体活化氧化氮氮三键和NO合成反应机理和界面反应机制。.本项目基于反应系统和滑动弧等离子体特性的优化和调控，实现了高NOx浓度和能量效率的等离子体空气一步固氮，并为可再生电能利用、清洁的固氮工艺工业化提供坚实的实验基础和理论支撑。