CAS: Bridging Surface Chemistry and Photophysics to Understand Photo-Electrochemical CO2 Reduction on Solar Photocathodes

CAS：连接表面化学和光物理学，了解太阳能光电阴极上的光电化学 CO2 还原

• 批准号: 2154416
• 负责人: Lawrence Baker
• 金额: $ 58.5万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154416&HistoricalAwards=false
• 关键词: CAS; Bridging; Surface; Chemistry; Photophysics

With the support of the Chemical Catalysis (CAT) and Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) programs in the Division of Chemistry, L. Robert Baker and Aravind Asthagiri of Ohio State University (OSU) are studying the conversion of CO2 to useful products using earth-abundant metal oxides as photocatalysts. The ability to reduce CO2 has the potential to close the carbon cycle and to stabilize the environmental impacts of CO2 emissions. Consequently, this project will help to address one of the pressing challenges for science and technology related to environmentally friendly energy production and chemical synthesis. Although much work has been performed to understand electrocatalysis on metal surfaces, semiconductor photocatalysts are more complex. In this project we will establish a combined experimental and theoretical framework to explore the knowledge gap between electrocatalysis on metal surfaces and photo-electrocatalysis on semiconductor surfaces. The research activities of this proposal will also be integrated with an outreach plan designed to improve student recruitment and retention in STEM (science, technology, engineering and mathematics) education. To accomplish this, the PIs will participate in the TEK8 undergraduate fellowship program at OSU. Through this program, undergraduate researchers gain hands-on research experience, which they then translate to middle school students through interactive, age-appropriate learning modules designed to expose students to real-world research challenges and inspire them to pursue STEM education. This research project, partnering L. Robert Baker and Aravind Asthagiri of Ohio State University, endeavors to increase understanding of the mechanistic details of the photocatalytic conversion of CO2 to useful products using earth-abundant metal oxides as catalysts. The study is built around a synergistic collaboration between theorist Asthagiri (density functional theory - DFT) and experimentalist Baker [vibrational sum frequency generation (VSFG) and element-specific, extreme ultraviolet (XUV) spectroscopy]. These studies will focus on photo-electrocatalysis experiments using CuFeO2 as a model p-type semiconductor showing high selectivity for CO2-reduction. In Aim 1, DFT calculations will investigate the free energy of elementary steps during CO2-reduction on CuFeO2 and generate predictions of stable surface intermediates. Direct observation of surface species by operando SFG spectroscopy will test these predictions in order to refine theoretical models of the surface reaction mechanism. Aim 2 will extend these studies to ultrafast time-resolved SFG in order to detect transient surface intermediates and reveal the branching pathways during the first proton/electron transfer to CO2. Spectroscopic results will be compared to DFT barrier height calculations showing the kinetics of various proton/electron transfer pathways. The goal of this aim will be to resolve between concerted proton coupled electron transfer (PCET) and sequential electron/proton transfer (ET/PT) and to illustrate how this branching point ultimately guides CO2R selectivity. Aim 3 will build on Aims 1 and 2 by investigating electron dynamics as a function of cation substitution in a series of p-type delafossite cathodes having the formula AFeO2 (A = Cu, Ag, and Au).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学催化（CAT）和化学结构，动力学和机制的支持下，俄亥俄州立大学（OSU）的L. Robert Baker和Aravind Atthagiri在化学划分中研究了CO2的转化，使用土壤丰富的金属氧化物作为PhotoCataLStss进行CO2的转换。 减少二氧化碳的能力有可能关闭碳循环并稳定二氧化碳排放的环境影响。 因此，该项目将有助于应对与环保能源生产和化学合成有关的科学和技术的紧迫挑战之一。 尽管已经进行了许多工作以了解金属表面上的电催化，但半导体光催化剂更为复杂。 在这个项目中，我们将建立一个合并的实验和理论框架，以探讨金属表面上的电催化与半导体表面上的光电催化之间的知识差距。 该提案的研究活动还将与旨在改善学生招聘和保留在STEM（科学，技术，工程和数学）教育中的外展计划相结合。 为此，PI将参加OSU的TEK8本科奖学金计划。 通过该计划，本科研究人员获得了动手研究经验，然后通过互动，适合年龄的学习模块转化为中学生，旨在使学生面临现实世界的研究挑战，并激发他们从事STEM教育。 该研究项目与俄亥俄州立大学的L. Robert Baker和Aravind Atthagiri合作，努力提高人们对使用土壤丰富的金属氧化物作为催化剂的二氧化碳转化到有用产品的机械细节的理解。这项研究围绕理论家Atthagiri（密度功能理论-DFT）与实验性面包师[振动总和频率产生（VSFG）和特定于元素特异性的极端紫外线（XUV）光谱法之间的协同合作构建。 这些研究将重点介绍使用CUFEO2作为模型P型半导体的光电催化实验，显示出高选择性的CO2还原性。 在AIM 1中，DFT计算将研究CUFEO2二氧化碳减少过程中基本步骤的自由能，并产生稳定表面中间体的预测。 通过Operando SFG光谱对表面物种的直接观察将测试这些预测，以完善表面反应机制的理论模型。 AIM 2将将这些研究扩展到超快时间分辨的SFG，以检测瞬态表面中间体并在第一个质子/电子转移到CO2期间揭示分支途径。 光谱结果将与DFT屏障高度计算进行比较，以显示各种质子/电子转移途径的动力学。该目标的目的是解决协同的质子耦合电子传输（PCET）和顺序电子/质子转移（ET/PT），并说明该分支点最终如何指导CO2R选择性。 AIM 3将通过对电子动力学进行调查作为阳离子替代的函数在一系列具有配方AFEO2公式的P型delafossite阴极中（a = cu，ag和au）中的函数来建立目标1和2，这反映了NSF的立法任务，并被认为是通过基金会的智力评估来评估的，并且值得通过评估来进行评估。