Combined Catalytic Conversion of CH4 and CO2 to Value-added Products over the Oxide Supported Metal Catalysts from DFT-based Multiscale Study

摘要题目：由人为温室气体（主要是二氧化碳）引起的气候变化被广泛认为是人类面临的主要威胁。在生产有用的化学品或液体燃料中回收二氧化碳将补充碳捕获和封存，并对全球二氧化碳水平产生积极影响，但这种过程需要能源或氢资源。南伊利诺伊大学卡本代尔分校（SIU）的葛庆峰教授提出在联合催化转化过程中利用甲烷作为氢和能源。甲烷部分氧化反应与甲烷与二氧化碳偶联反应的耦合克服了偶联反应的热力学限制，从而为甲烷和二氧化碳的原子高效利用提供了一条途径。阐明甲烷与二氧化碳复合转化的催化机理有助于改进催化剂的工作原理，并有助于新催化剂的理论设计。葛教授将利用新加坡国立大学卡本代尔分校的现有机制，从代表性不足的群体中招募学生，参与拟议的前沿研究活动。拟议的研究计划有助于SIU卡本代尔？通过加强研究和教育基础设施，努力建设一所以学生为中心，在能源和纳米材料等领域具有研究实力的研究型大学。该研究计划采用基于第一性原理的多尺度方法来研究金属-载体相互作用及其对CH4和CO2催化转化为增值产品（包括乙酸、醇等）的影响。在开发C-C偶联氧化反应的过程中，最大的挑战是控制氧化剂的强度。过强的氧化剂会使甲烷过度氧化，使反应偏离偶联途径。提出的研究重点之一是测试可还原性ZrO2， CeO2和混合氧化物作为氧载体以及对选定的过渡金属（包括Fe， Co， Ni和Rh）的支持。通过对氧化物表面和不同尺寸的支撑金属团簇进行热力学分析，确定反应环境对反应条件下支撑氧化物和支撑金属团簇稳定性的影响。基本的断键和成键步骤，包括碳氢键和碳氧键的断键和碳碳键的形成。机制理解和能量信息将被整合到动力学蒙特卡罗（kMC）或基于平均场近似的微动力学模拟中，以提供可以直接与实验测量进行比较的表观动力学参数。这项研究将有助于设计防止甲烷完全燃烧的催化剂。拟议的研究计划建立在PI在表面科学和催化方面的经验以及最近在二氧化碳活化和氢化方面的工作基础上。与外部实验小组的合作将提供一种机制来测试和验证来自拟议研究的预测和想法。

Abstract Title: Combined Catalytic Conversion of Methane and Carbon Dioxide to Value-added Products over the Oxide Supported Metal Catalysts from Multiscale Modeling Climate change resulting from anthropogenic green house gases, mainly carbon dioxide, is widely considered as a major threat faced by mankind. Recycling carbon dioxide in the production of useful chemicals or liquid fuel will complement carbon capture and sequestration and have a positive impact on global carbon dioxide levels, but such a process requires energy or hydrogen sources. Professor Qingfeng Ge of Southern Illinois University (SIU) Carbondale proposes to exploit methane as both hydrogen and energy source in a combined catalytic conversion process. Coupling methane partial oxidation reaction with the methane and carbon dioxide coupling reaction overcomes the thermodynamic limitation of the coupling reaction, thereby providing an atomically efficient route to utilize methane and carbon dioxide. Elucidating the catalytic mechanism of combined methane and carbon dioxide conversion will help improve the working catalysts and aid the rationale design of the new ones. Professor Ge will utilize the existing mechanisms at SIU Carbondale to recruit students from underrepresented groups to participate in the proposed cutting-edge research activities. The proposed research program contributes to the SIU Carbondale?s effort to build a student-centered research university with research strength in areas including energy and nanomaterials by enhancing the infrastructure for research and education. The proposed research program applies a first principles based multiscale approach to investigate metal-support interaction and its effect on catalytic conversion of CH4 and CO2 to value-added products, including acetic acid, alcohols, etc. A great challenge in developing a process that couples oxidation reaction with C-C coupling is to control the strength of oxidants?a too strong oxidant would over-oxidize methane and drive the reaction away from the coupling pathway. One focus of the proposed research is to test the reducible ZrO2, CeO2, and mixed oxides as oxygen carrier as well as support for selected transition metals, including Fe, Co, Ni and Rh. Thermodynamics analyses of the oxide surfaces together with the supported metal clusters of varying sizes will be performed to establish the effect of reaction environment on the stability of supporting oxides and supported metal clusters under reaction conditions. Elementary bond breaking and making steps, including C-H and C-O bond breaking and C-C bond formation, will be followed. The mechanistic understanding and energetic information will be integrated into a kinetic Monte Carlo (kMC) or mean-field approximation based micro-kinetic simulation to provide apparent kinetic parameters that may be compared directly with the experimental measurements. The proposed research will help to design catalysts that prevent complete combustion of methane. The proposed research program is built upon the experiences of the PI in surface science and catalysis and recent work on CO2 activation and hydrogenation. Collaborations with external experimental groups will provide a mechanism to test and validate the predictions and ideas from proposed research.