Rh和Pt团簇催化净化汽车尾气反应机理的理论研究

以减少和消除汽车尾气污染为背景，降低尾气净化催化剂中贵金属用量为目标，采用密度泛函理论、量子力场和分子力场相结合、分子动力学模拟、表面动力学模拟等方法，以NO还原和烷烃裂解为模型反应，设计适宜的RhnMm和PtnMm (M = Ni和La 等)团簇模型，研究催化剂活性组分团簇对NO还原和烷烃裂解催化反应的影响，探求温度和压力对其动态催化反应活性和选择性影响的实质，阐明催化反应机理，获取决定催化效率的关键过渡态和中间体，积累NO还原和烷烃裂解催化反应的热力学和动力学参数（如反应速率常数和产物选择性等），明确非贵金属助剂对Rh和Pt团簇模型催化剂结构和性能的影响。为设计合成降低Rh和Pt用量的新型高效廉价的汽车尾气净化催化剂提供理论依据。对探索复杂体系动力学规律、控制和治理环境污染、创新低碳技术具有重要意义。

Catalytic conversion of automobile exhaust, such as the reduction of NOx and hydrocarbon cracking, is a major challenge in environment and catalysis research because of the green house effect of these gases. Rh-based and Pt-based catalysts are the components responsible for the removal of NO and the cracking of hydrocarbons,respectively. The density functional theory, quantum mechanics, molecular mechanics, molecular dynamic simulation, and surface kinetic simulation methods are explored to investigate the above catalytic reaction mechanisms. The contents of the present investigation are as follows: (a) to design RhnMm and PtnMm (M = Ni and La et al)clusters, (b) to provide insight into the intrinsic property and catalytical efficiency of the purification of automobile exhaust on RhnMm and PtnMm cluster, (c) to explore the effect of temperature and pressure on the reactivity and selectivity of dynamic purification of automobile exhaust, (d) to accumulate the thermodynamic and kinetic data, e.g. rate constant and branching ratio of products under different temperature and pressure, and the difference of Gibbs free energy, (e) to acquire the determining transition state and intermediate of catalytic turnover frequency, and (f) to elucidate the effect of nonnoble-metal promoter on the structure and property of Rh-based and Pt-based catalysts. The the present investigation is helpful to the understand the nature of catalytic reactions, and design and develop effective, cheap, and practical catalysts for the removal of automobile exhaust. It is very important to explore the rule of the complicated system kinetics, to control and remove envirnomeantal pollution, and innovate the low-carbon technology.