Collaborative Research: Combining Models and Experiment for Quantitative Characterization of Electrocatalytic Carbon Dioxide Reduction on Doped Ceria

该项目研究了一种高温电化学方法，用于将二氧化碳（CO2）气体中的碳转化为更高价值的含碳产品，如碳氢化合物燃料，从而成为可再生能源发电最终封闭碳循环过程的关键组成部分。 具体而言，该项目将研究在高温氧化铈电极上将二氧化碳还原为一氧化碳（CO），利用实验技术，理论模型和统计方法的组合来区分已提出但尚未验证的各种反应机制。 由此产生的理解将提供指导，设计固体氧化物电极，提高效率和耐用性。薄膜测试电池与氧化铈工作电极氧化钇稳定的氧化锆（YSZ）电解质将被制造，暴露于CO和CO2的气体，并在高温下极化。 由极化引起的膜中的电势梯度产生作为离集电器的距离的函数的表面电势的梯度。这些表面电位的变化-一个与氧化铈表面活性中间体浓度密切相关的量-将在电池运行期间使用操作中高温扫描表面电位显微镜（HT-SSPM）以低于100 nm的横向分辨率进行测量。这些数据，沿着全电池电化学阻抗谱数据（EIS），将收集不同实验条件的矩阵，包括气体成分，温度，施加的电池电位，掺杂剂浓度和热老化的变化。 电催化相场建模（EPFM），它耦合的催化反应的机理模型与材料的行为的氧化铈电极，将定量校准到整个实验数据集使用贝叶斯模型为基础的分析（BMA）。在本项目的过程中产生的模型和得出的结论将是有用的高温，混合离子电子导电催化剂的进一步发展。贝叶斯校准使最先进的操作中HT-SSPM和EPFM方法的独特耦合成为可能，贝叶斯校准定量地将大型实验数据集和复杂模型联系起来，从而沿着对模型参数的估计（具有不确定性量化）以及根据数据对模型拟合度的评估。 BMA还提供了将关键参数的现有测量或计算（包括量子计算）纳入分析的机会。 除了技术要素外，该项目还将包括一项针对高中物理学生的实验室活动，该活动将在研究人员所在的当地社区开展，并在全国范围内宣传。

The project investigates a high-temperature electrochemical approach for converting the carbon in carbon dioxide (CO2) gas to higher value carbon-containing products such as hydrocarbon fuels, thereby serving as a critical component in eventual closed carbon-cycle processes for renewable energy generation. Specifically, the project will investigate the reduction of carbon dioxide to carbon monoxide (CO) on high-temperature cerium oxide based electrodes utilizing a combination of experimental techniques, theoretical models, and statistical methods to distinguish between various reaction mechanisms that have been proposed but remain unverified. The resulting understanding will provide guidance for designing solid oxide electrodes with improved efficiency and durability.Thin-film test cells with ceria working electrodes on yttria-stabilized zirconia (YSZ) electrolytes will be fabricated, exposed to CO and CO2-containing gases and polarized at high temperature. The potential gradient in the film caused by the polarization yields a gradient in the surface potential as a function of distance from the current collector. These changes in surface potential - a quantity closely related to the concentrations of active intermediates on the ceria surface - will be measured, during cell operation, with sub-100 nm lateral resolution utilizing in-operando high-temperature scanning surface potential microscopy (HT-SSPM). These data, along with full-cell electrochemical impedance spectroscopy data (EIS), will be collected for a matrix of different experimental conditions including changes in gas composition, temperature, applied cell potential, dopant concentration, and thermal aging. Electrocatalytic phase-field modeling (EPFM), which couples mechanistic models of the catalytic reaction with the material behavior of the ceria electrode, will be quantitatively calibrated to the entire experimental dataset using Bayesian model-based analysis (BMA). Models generated and conclusions drawn during the course of this project will be useful for further development of high-temperature, mixed ionic-electronic conducting catalysts. The unique coupling of state-of-the-art in-operando HT-SSPM and EPFM methods is made possible by Bayesian calibration, which quantitatively links large experimental datasets and complex models, leading to estimates of model parameters (with uncertainty quantification) along with assessments of the model fitness in light of the data. BMA also affords the opportunity to incorporate existing measurements or calculations (including quantum calculations) of key parameters in the analysis. In addition to the technical elements, the project will include a lab activity for high school physics students that will be developed in the researchers' local communities and publicized nationally.