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

该项目研究一种高温电化学方法，将二氧化碳(CO2)气体中的碳转化为碳氢燃料等价值更高的含碳产品，从而成为最终闭合碳循环过程中的关键组成部分，用于可再生能源发电。具体地说，该项目将利用实验技术、理论模型和统计方法相结合的方法，研究高温氧化铈电极上二氧化碳还原为一氧化碳(CO)的过程，以区分已提出但仍未得到验证的各种反应机理。所获得的认识将为设计具有更高效率和耐用性的固体氧化物电极提供指导。将在YSZ电解液上制备具有CeO2工作电极的薄膜测试电池，暴露在含CO和CO2的气体中，并在高温下极化。由极化引起的膜中的电位梯度产生作为与集电体的距离的函数的表面电位的梯度。这些表面电位的变化--一个与CeO2表面活性中间体浓度密切相关的量--将在电池运行期间以低于100 nm的横向分辨率利用腔内高温扫描表面电位显微镜(HT-SSPM)进行测量。这些数据以及全电池电化学阻抗谱数据(EIS)将被收集用于不同实验条件的矩阵，包括气体组成、温度、施加的电池电位、掺杂浓度和热老化的变化。电催化相场模型(EPFM)耦合了催化反应的机理模型和CeO2电极的材料行为，将使用基于贝叶斯模型的分析(BMA)对整个实验数据集进行定量校准。本项目过程中所建立的模型和得出的结论将有助于进一步开发高温、离子-电子混合导电催化剂。最先进的操作中HT-SSPM和EPFM方法的独特耦合是通过贝叶斯校准实现的，贝叶斯校准将大型实验数据集和复杂模型定量地联系在一起，导致对模型参数的估计(通过不确定性量化)以及根据数据对模型适合性的评估。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，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发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.