SusChEM: CO2 Photo-Electrochemistry on Metal Oxides Surfaces Studied by Vibrational Sum Frequency Generation Spectroscopy and Density Functional Theory

SusChEM：通过振动和频发生光谱和密度泛函理论研究金属氧化物表面上的 CO2 光电化学

• 批准号: 1665280
• 负责人: Lawrence Baker
• 金额: $ 44.95万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-15 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1665280&HistoricalAwards=false
• 关键词: SusChEM; CO2; Photo; Electrochemistry; Metal

Catalysts are chemical substances that provide lower-energy reaction pathways to increase the speed of a chemical reaction. Catalysts can be recycled many times during a chemical reaction. Some catalysts, called photo-electrocatalysts, are able to use light as an energy source to produce the reaction of interest. In this project, funded by the Chemical Catalysis Program of the Chemistry Division, Professors L. Robert Baker and Aravind Asthagiri are using a combination of an experimental technique called sum frequency generation (SFG) vibrational spectroscopy and computational modeling called density functional theory (DFT) to investigate carbon dioxide (CO2) reduction by a series of copper and copper/iron containing photo-electrocatalysts. SFG vibrational spectroscopy is able to show how molecules important in CO2 reduction interact with the catalyst surfaces during the reaction. DFT calculations are used to help explain the SFG data generated during the reaction. The combination of the two techniques leads to a complete picture of the surface reaction mechanism, allowing for better design of the catalyst and the photo-electrocatalysis process. The ability to photo-electrochemically reduce CO2 using sunlight has the potential to enable us to recycle carbon and stabilize the environmental impacts of CO2 emissions from automobiles and other sources. This research helps to address the challenge of making fuels in an environmentally friendly and economically viable way. These research activities are integrated with an outreach plan to improve student recruitment and retention in science, technology, engineering and mathematics (STEM) fields. Through the TEK8 program at the Ohio State University, undergraduate students and K-12 teachers gain hands-on experience in the investigators' research groups. The students then translate this experience to middle school students through age-appropriate learning modules designed to inspire K-12 students to pursue future STEM education.The challenge of understanding CO2 surface chemistry on a photo-electrocatalyst requires a combined knowledge of metal oxide surface chemistry as well as the semiconductor photo-physics that determine the localized atomic sites of photo-excited electrons responsible for driving the reductive chemistry. In this project funded by the Chemical Catalysis Program of the Chemistry Division, Professors L. Robert Baker and Aravind Asthagiri are using sum frequency generation (SFG) spectroscopy and complementary density functional theory (DFT) computational modeling to investigate CO2 activation and subsequent reduction on a series of CuO/CuFeO2 surfaces as a function of relative phase composition. CuO/CuFeO2 catalysts with varying amounts of CuO and CuFeO2 show tunable selectivity between acetate and formate production. The ability to probe the molecular intermediates associated with these reaction pathways, coupled with the ability to tune these relative rates, is providing a valuable case study for a thorough mechanistic investigation of the surface properties that mediate reaction kinetics leading to tunable selectivity for CO2 reduction. Complementary measurements using femtosecond soft x-ray spectroscopy show electron thermalization kinetics and site-specific charge localization with element specificity. Through information from the soft x-ray spectroscopy and DFT-derived band structure, the team obtains the reduction potential of site-localized photo-excited electrons in the oxide surface and compares these potentials to the calculated change in free energy of formation of elementary steps on these respective atomic sites. This combination of approaches bridges the fields of semiconductor photo-physics with surface chemistry and catalysis in order to provide a fundamental framework for understanding the selectivity of CO2 photo-electrochemistry on metal oxides surfaces. This research helps to address the challenge of environmentally friendly and economically stable fuel production and chemical synthesis from CO2 using earth-abundant metal oxide catalysts. These research activities are integrated with an outreach plan to improve student recruitment and retention in STEM fields. Through the TEK8 program at the Ohio State University, undergraduate students and K-12 teachers gain hands-on experience in the investigators' research groups. They then translate this experience to middle school students through age-appropriate learning modules designed to inspire K-12 students to pursue future STEM education.

催化剂是提供较低能量反应途径以提高化学反应速度的化学物质。 催化剂在化学反应过程中可以多次循环利用。 一些称为光电催化剂的催化剂能够使用光作为能源来产生感兴趣的反应。 在该项目中，由化学部化学催化项目资助，L. Robert Baker 和 Aravind Asthagiri 教授结合使用了称为和频发生 (SFG) 振动光谱的实验技术和称为密度泛函理论 (DFT) 的计算模型研究一系列铜和含铜/铁的光电催化剂还原二氧化碳（CO2）。 SFG 振动光谱能够显示在 CO2 还原过程中重要的分子如何在反应过程中与催化剂表面相互作用。 DFT 计算用于帮助解释反应过程中生成的 SFG 数据。 两种技术的结合可以全面了解表面反应机制，从而可以更好地设计催化剂和光电催化过程。 利用阳光以光电化学方式减少二氧化碳的能力有可能使我们能够回收碳并稳定汽车和其他来源的二氧化碳排放对环境的影响。 这项研究有助于解决以环保且经济可行的方式制造燃料的挑战。 这些研究活动与外展计划相结合，以提高科学、技术、工程和数学 (STEM) 领域的学生招募和保留率。 通过俄亥俄州立大学的 TEK8 项目，本科生和 K-12 教师可以在研究人员的研究小组中获得实践经验。 然后，学生们通过适合年龄的学习模块将这种经验转化为中学生，旨在激励 K-12 学生追求未来的 STEM 教育。理解光电催化剂上的 CO2 表面化学的挑战需要金属氧化物表面化学的综合知识以及确定负责驱动还原化学的光激发电子的局部原子位点的半导体光物理学。 在这个由化学部化学催化项目资助的项目中，L. Robert Baker 和 Aravind Asthagiri 教授正在使用和频发生 (SFG) 光谱和互补密度泛函理论 (DFT) 计算模型来研究二氧化碳的活化和随后的还原。系列 CuO/CuFeO2 表面作为相对相组成的函数。 具有不同 CuO 和 CuFeO2 含量的 CuO/CuFeO2 催化剂在乙酸盐和甲酸盐生产之间表现出可调的选择性。 探测与这些反应途径相关的分子中间体的能力，加上调整这些相对速率的能力，为对介导反应动力学的表面特性进行彻底的机械研究提供了有价值的案例研究，从而实现了二氧化碳还原的可调选择性。 使用飞秒软 X 射线光谱的补充测量显示了电子热化动力学和具有元素特异性的位点特定电荷定位。 通过软X射线光谱和DFT衍生的能带结构的信息，研究小组获得了氧化物表面中定域光激发电子的还原电势，并将这些电势与计算出的基本步骤形成自由能的变化进行比较在这些各自的原子位点上。 这种方法的结合将半导体光物理与表面化学和催化领域联系起来，以便为理解金属氧化物表面上二氧化碳光电化学的选择性提供一个基本框架。 这项研究有助于解决环境友好且经济稳定的燃料生产以及使用地球上丰富的金属氧化物催化剂从二氧化碳进行化学合成的挑战。 这些研究活动与外展计划相结合，以提高 STEM 领域的学生招募和保留率。 通过俄亥俄州立大学的 TEK8 项目，本科生和 K-12 教师可以在研究人员的研究小组中获得实践经验。 然后，他们通过适合年龄的学习模块将这种经验转化为中学生，旨在激励 K-12 学生追求未来的 STEM 教育。

项目成果

The role of phase impurities and lattice defects on the electron dynamics and photochemistry of CuFeO2 solar photocathodes

• DOI: 10.1007/s12274-019-2493-6
• 发表时间: 2019-08
• 期刊: Nano Research
• 影响因子: 9.9
• 作者: E. Fugate;S. Biswas;Mathew C. Clement;Minkyu Kim;Dongjoon Kim;A. Asthagiri;L. R. Baker

Plasmon-Resonant Vibrational Sum Frequency Generation of Electrochemical Interfaces: Direct Observation of Carbon Dioxide Electroreduction on Gold

电化学界面的等离子共振振动和频率生成：金上二氧化碳电还原的直接观察

• DOI: 10.1021/acs.jpca.0c04268
• 发表时间: 2020
• 期刊: The Journal of Physical Chemistry A
• 作者: Wallentine, Spencer;Bandaranayake, Savini;Biswas, Somnath;Baker, L. Robert
• 通讯作者: Baker, L. Robert