基于钙钛矿型氧化物的高分散限域型多金属甲烷化催化剂的构筑及催化性能研究

The development of excellent and efficient methanation catalyst is the key of coal-to-natural gas. The introduction of additives is one of the effective methods to improve the activity and anti-sintering performance of Ni-based catalysts. However, it is difficult to ensure the highly dispersion and interaction of active metal and additive by the conventional preparation method, and the catalytic effect of the additive cannot be maximized. In this project, we propose to prepare high dispersed and thermal-stable multi-metal methanation catalyst based on perovskite-type oxides and confinement effect of support. The perovskite-type oxides LaNi1-xMxO3 are prepared by controlling the types of additives and their proportions with active metals. The physicochemical structural evolution of the active sites during the reduction process and the effects of these structures on the catalytic properties are analyzed to achieve the controllable preparation of active sites M-Ni/La2O3. Then, using metal ion complexation with organic additive-assisted impregnation to prepare the multi-metal catalyst based SBA-15 in which the precursor LaNi1-xMxO3 was highly dispersed in the channels of the support. The intrinsic relationship between the catalytic performance and the structure of the catalyst was established. On this basis, the reaction kinetics was studied. Finally, we want to obtain a high dispersed and thermal-stable catalyst for CO methanation and provide a theoretical guidance for the design of other supported catalysts.

开发优良高效的甲烷化催化剂是煤制天然气的关键，引入助金属是目前提高Ni基催化剂活性和抗烧结性能的主要方法之一。但传统的制备方法很难保证活性金属与助金属的高度均匀分散，助金属的促催化效应不能得到最大程度发挥。本项目拟基于钙钛矿型氧化物和分子筛限域效应，获得高分散高热稳定性的多金属甲烷化催化剂。通过调控助金属类型及其与活性金属配比制备钙钛矿型氧化物LaNi1-xMxO3，并对其还原过程中活性位的物理化学结构演变规律以及这些结构变化对催化性能的影响进行分析，实现活性位M-Ni/La2O3的可控制备。然后，以SBA-15为载体，结合金属离子络合法和有机添加剂辅助浸渍法，实现以LaNi1-xMxO3为前驱体的高度分散于载体孔道内的多金属催化剂的制备，建立催化剂性能及其结构的内在关系，并在此基础上对反应动力学进行研究，最终获得高分散高热稳定性的CO甲烷化催化剂，并为其他负载型催化剂的设计提供理论指导。

近年来，随着全球的能源格局的改变，以及我国可持续发展的需求，中国的能源消费结构逐步向高效、清洁、低碳的方向发展，市场对天然气的需求日益扩大，为了清洁高效地利用我国丰富的煤炭资源来弥补天然气的缺口，需开展煤制天然气项目，其核心是CO 甲烷化技术。开发优良高效的甲烷化催化剂是煤制天然气的关键，引入助金属是目前提高Ni基催化剂活性和抗烧结性能的主要方法之一。但传统的制备方法很难保证活性金属与助金属的高度均匀分散，助金属的促催化效应不能得到最大程度发挥。本项目拟基于钙钛矿型氧化物和分子筛限域效应，获得高分散高热稳定性的多金属甲烷化催化剂。通过调控助金属类型及其与活性金属配比制备钙钛矿型氧化物LaNi1-xMxO3，并对其还原过程中活性位的物理化学结构演变规律以及这些结构变化对催化性能的影响进行分析，实现活性位M-Ni/La2O3的可控制备。然后，以SBA-15为载体，结合金属离子络合法和有机添加剂辅助浸渍法，实现以LaNi1-xMxO3为前驱体的高度分散于载体孔道内的多金属催化剂的制备，建立催化剂性能及其结构的内在关系。