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

摘要标题：氧化物负载金属催化剂上甲烷和二氧化碳的联合催化转化为附加值产品多尺度模拟温室气体引起的气候变化，主要是二氧化碳，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时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，但这样的过程需要能源或氢气来源。南伊利诺伊大学(SIU)Carbondale的葛庆峰教授建议在联合催化转化过程中利用甲烷作为氢气和能源。将甲烷部分氧化反应与甲烷和二氧化碳偶联反应偶联，克服了偶联反应的热力学限制，从而为甲烷和二氧化碳的利用提供了一条原子上有效的途径。阐明甲烷和二氧化碳联合转化的催化机理将有助于改进现有的工作催化剂，并有助于新催化剂的合理设计。葛教授将利用SIU Carbondale的现有机制，从代表性不足的群体中招募学生参加拟议的尖端研究活动。拟议的研究项目有助于SIU Carbondale？S努力通过加强研究和教育的基础设施，建立一所以学生为中心的研究型大学，在能源和纳米材料等领域拥有研究实力。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甲烷和二氧化碳催化转化为增值产物的影响，包括醋酸、醇等。开发一种将氧化反应与C-C偶联耦合起来的过程的一个巨大挑战是控制氧化剂的强度？过强的氧化剂会过度氧化甲烷，并使反应远离耦合途径。建议的研究重点之一是测试可还原的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)的载体。对氧化物表面和不同大小的负载型金属团簇进行热力学分析，以确定反应环境对负载型氧化物和负载型金属团簇在反应条件下稳定性的影响。将遵循基本的键断裂和制造步骤，包括C-H和C-O键断裂和C-C键的形成。力学理解和能量信息将被集成到基于动力学蒙特卡罗(KMC)或平均场近似的微观动力学模拟中，以提供可直接与实验测量相比较的表观动力学参数。这项拟议的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的基础上。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.