Facilitating the Rational Design of Active Sites for the Oxygen Evolution Reaction on 3d Transition Metal Oxide Catalysts

拟议的工作将包括开发新的方法以及应用现有的方法，以了解3D过渡金属氧化物表面上活性中心的放氧反应(OER)活性如何与活性中心的结构(几何和组成)相关。这将使我们能够确定导致最高OER活性的活性部位的性质，以及在这样的部位上发生反应的机理。这将为今后的实验和计算寻找实用的多相析氧催化剂提供有价值的指导。此外，我们将在量子化学水平上寻求对这种结构-活性关系的理解。周期密度泛函理论(DFT)的计算将被用来确定催化中间体的能量和反应步骤的速率常数，然后将其用于动力学模型，以预测几种不同机理的催化循环的周转频率和速率控制步骤。计算将包括与电解液的连续介质模型的相互作用，并将在活性中心的带电状态和中性状态下执行。后一项任务将需要开发一种在周期性密度泛函框架内计算带电活性中心自由能的方法，这是固-液界面催化中经常遇到的一种情况，目前还不存在普遍适用且计算成本较低的方法。我们将使用并进一步开发新的约束方法来检查活性中心的局部电子结构，以了解不同金属氧化物的电子结构如何变化，以及这与催化活性的关系。

The proposed work will involve the development of new methods as well as the application of existing methods to obtain an understanding of how the activity for the oxygen evolution reaction (OER) of an active site on a 3D transition metal oxide surface is related to the structure (geometry and composition) of the active site. This would enable us to identify the properties of an active site leading to highest OER activity, as well as the mechanism by which the reaction occurs on such a site. This would provide valuable guidance for future experimental and computational search for a practical heterogeneous oxygen evolution catalyst. Additionally we will seek an understanding of this structure-activity relationship at the quantum chemical level. Periodic density functional theory (DFT) calculations will be used to determine the energetics of catalytic intermediates and rate constants for reaction steps which will then be used in a kinetic model to predict the turnover frequency and rate controlling step of the catalytic cycle for several different mechanisms. The calculations will include interactions with a continuum model of the electrolyte and will be performed on charged as well as neutral states of the active site. This latter task will require the development of a method for calculating free energies of charged active sites within the framework of periodic DFT, a frequently encountered situation in catalysis at the solid-liquid interface for which a universally applicable and computationally inexpensive approach does not currently exist. Novel constraining methods for examining the local electronic structure of the active site that were previously developed in our group will be used and further developed to understand how the electronic structure varies across the different metal oxides and how this relates to the catalytic activity.