Alkane Activation at Catalytic Metal Surfaces: A Coupled Experimental and Theoretical Study of Reaction Dynamics and Energy Transfer at the Gas-Surface Interface

化学分部的化学结构、动力学和机理项目支持弗吉尼亚大学的Ian Harrison教授对催化金属表面烷烃活化的研究：反应动力学和气体表面界面能量传递的耦合实验和理论研究。将使用加热的射流分子束剂量剂在可变气体温度下将C1-C9烷烃分子撞击到表面上，从而可以克服离解化学吸附的激活障碍。解离黏附系数将被测量，多维实验数据将用于测试和开发气体表面反应性的理论模型。结合本文测量的射流分子束结果、现有的超声速分子束解离粘接测量、电子结构理论计算和动力学建模，讨论了分子旋转、振动效率、烷烃复杂性、表面结构、气体和表面温度、早/晚过渡态势垒位置以及气体表面能量传递对解离粘接的影响。本研究将实验表征和理论模拟C1-C9烷烃在催化金属表面的活化。这项研究的目标是获得对表面烷烃活化解离的分子水平的理解，这通常被认为是烷烃催化转化为更有价值的化学物质（如氢、合成气、烯烃或燃料）的限速步骤。烷烃是生物质转化的目标产物，在寻求有效地将可再生生物质转化为燃料时，烷烃的节能和选择性催化是可取的。重要的是，一群不同的年轻研究生和本科生将通过与关键社会目标相关的基础科学实验和理论工作，在表面科学，催化和反应动力学等跨学科领域接受教育，即工程可持续能源的未来。少数族裔本科生将作为弗吉尼亚大学夏季科学鼓励计划的一部分接受教学和接待，学生将在此学习可再生能源研究。研究生将被鼓励并在当地小学继续他们的扩展实验室演示。

The Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division supports Professor Ian Harrison, University of Virginia, for studies of Alkane Activation at Catalytic Metal Surfaces: A Coupled Experimental and Theoretical Study of Reaction Dynamics and Energy Transfer at the Gas-Surface Interface. A heated effusive molecular beam doser will be used to impinge C1-C9 alkane molecules at variable gas temperature onto a surface such that activation barriers for dissociative chemisorption can be surmounted. Dissociative sticking coefficients will be measured and the multidimensional experimental data will be used to test and develop theoretical models of gas-surface reactivity. Using the combination of the effusive molecular beam results to be measured here, existing supersonic molecular beam dissociative sticking measurements, electronic structure theory calculations, and kinetic modeling the effects of molecular rotation, vibrational efficacy, alkane complexity, surface structure, gas and surface temperatures, early/late transition state barrier position, and gas-surface energy transfer on dissociative sticking will be addressed.This research will experimentally characterize and theoretically model the activation of C1-C9 alkanes at catalytic metal surfaces. The research will be directed towards gaining a molecular-level understanding of the activated dissociation of alkanes at surfaces, which is oftentimes believed to be the rate limiting step in the catalytic transformations of alkanes into more valuable chemicals such as hydrogen, synthesis gas, alkenes, or fuels. Alkanes are a targeted product of biomass reforming and more energy efficient and selective catalysis of alkanes is desirable in the quest to efficiently convert renewable biomass to fuels. Importantly, a diverse group of young graduate and undergraduate students will be educated in the interdisciplinary fields of surface science, catalysis, and reaction dynamics through coupled experimental and theoretical work on basic science relevant to a key societal goal, namely, engineering a sustainable energy future. Minority undergraduates will be taught and hosted as part of a summer science encouragement program at the University of Virginia whereby students will learn about renewable energy research. Graduate students will be encouraged and continue in their outreach laboratory demonstrations at local elementary schools.