Intrinsic Barriers as a Guide to Rates and Mechanisms of Reactions on Solid Surfaces

9610115美国伊利诺伊大学香槟分校理查德·I·梅塞尔教授由化学反应过程-动力学和催化计划资助，继续他对有机小分子在过渡金属模型表面吸附的研究。他将继续发展一种理论方法来预测表面化学机制。理论模型的基本假设是气相分解反应的本征势垒等于表面分解反应的本征势垒。在实验上，该模型用EELS和TPD光谱仪进行了测试。在这项工作中，Masel建议根据有机分子中的取代基或共吸附物的存在以及化学吸附表面的性质等参数，对C-C、C-O、C-H和O-H键断裂的本征势垒进行更详细的表征。它的重点是测量特定测试反应的反应热、键能和本征活化势垒，并将借助计算量子化学对其进行模型预测。还将评估净电荷在本征势垒模型中的作用。该研究对催化和表面化学的理论和实践具有重要意义。

ABSTRACT CTS 9610115 Richard I. Masel Professor Richard I. Masel, of the University of Illinois, Urbana-Champaign, is being funded by the Chemical Reactions Processes-Kinetics and Catalysis program to continue his studies of adsorption of small organic molecules on model transition metal surfaces. He will continue to develop a theoretical approach to predicting surface chemical mechanisms. The basic hypothesis of the theoretical model is that intrinsic barriers calculated for decomposition reactions in the gas phase are equal to the intrinsic barriers for those decompositions on surfaces. Experimentally, the model is tested with EELS and TPD spectroscopies. In this work, Masel proposes to do more detailed characterization of the intrinsic barriers for C-C, C-O, C-H and O-H bond scissions, in terms of parameters such as substituent groups in the organic molecules or presence of coadsorbates, and nature of the chemisorbing surface. It is focused on the measurement of heats of reaction, bond energies, and intrinsic activation barriers for specific test reactions, for which model predictions will be made with the aid of computational quantum chemistry. The role of net charges in the intrinsic barrier model will also be assessed. This research is of major significance for the theory and practice of catalysis and surface chemistry.