Ni基分子筛重整催化剂的等离子体可控制备及其构效关系研究

The catalytic performance of nickel-based catalysts for synthesis of syngas by CO2/CH4 reforming is closely related to their structure, e. g. the agglomerated active component nickel and carbon. The particle size of active metal Ni and interaction force between active metal Ni and carrier of the supported nickel-based catalysts are difficult to control during the traditional impregnation and high temperature roasting process, and the active metal Ni agglomeration is easy to form carbon deposit in the high-temperature reaction, which have became the important factors affecting their catalytic performance. In order to improve activity and stability, the active metal particle structure (particle size and nickel-support interaction) controllable preparation is the important scientific issues. In this project, the introduction strategy of the cold glow discharge plasma technology was designed based on mesoporous composite molecular sieves with high specific surface area and thermal stability. The particle size of Ni metal was controlled to nano-size by changing the way of plasma introduction. The controllable preparation of Ni particle size and the interaction force between Ni particle size and carrier were achieved by changing the parameters of plasma discharge medium, power and time. Based on the characterization results, the mechanism of nickel particle size and its nickel-support interaction was studied. The relationship between catalyst activity, stability, carbon deposition resistance, structural properties of active component (particle size, interaction nickel-support interaction, etc.) and the plasma treatment parameters was explained. The reforming activity and stability of the Ni-based catalyst were studied. It provides a new idea for the controllable preparation of Ni-based catalysts for CO2/CH4 reforming reactions.

CO2/CH4重整用镍基催化剂性能与其结构密切相关。负载型镍基催化剂在传统浸渍-高温焙烧过程中，活性金属镍i粒径不易控制，且与载体相互作用力不易调变，易高温团聚，导致积碳，成为影响其催化性能的重要因素；为了提高活性和稳定性，活性金属颗粒结构（颗粒尺寸、Ni-载体之间相互作用）调控是受关注的重要科学问题。本项目以高比表面积高热稳定性介孔复合分子筛为载体，设计冷等离子体引入策略，通过改变等离子体引入方式，控制金属Ni粒径至纳米尺寸；通过改变等离子体的放电介质，功率和时间等参数，实现Ni粒径及其与载体之间相互作用力的可控制备。结合表征分析，研究活性组分镍的粒径尺寸及其与载体相互作用力的调控机制，阐释催化剂活性、稳定性、抗积碳性和活性组分结构性质(颗粒尺寸、其与载体的作用力等)及等离子体处理过程的各参数之间的关系，研究Ni基催化剂重整活性和稳定性的影响规律，为重整用Ni基催化剂可控制备提供新方法。

本项目针对负载型镍基催化剂在传统浸渍-高温焙烧过程中，活性金属镍粒径不易控制，且与载体相互作用力不易调变，易高温团聚，导致积碳这一重要科学问题，设计并合成了高比表面积高热稳定性介孔复合分子筛为载体；再以醇类进行催化剂的表面改性，并设计冷等离子体引入策略，通过改变等离子体引入方式，控制金属Ni粒径至纳米尺寸；通过改变等离子体的放电介质，功率和时间等参数，开展了醇+等离子体和助剂+等离子体共作用制备重整催化剂，实现Ni粒径及其与载体之间相互作用力的可控制备，提高了重整催化剂的活性和稳定性。结合表征分析，研究了活性组分镍的粒径尺寸及其与载体相互作用力的调控机制，阐释了催化剂活性、稳定性、抗积碳性和活性组分结构性质(颗粒尺寸、其与载体的作用力等)及等离子体处理过程的各参数之间的关系，探讨了影响Ni基催化剂重整活性和稳定性的规律，为重整用Ni基催化剂可控制备提供新方法和新策略。