CAREER: Understanding Bifunctionality in Organic Electro-oxidation Catalysis

职业：了解有机电氧化催化中的双功能

• 批准号: 1944834
• 负责人: Adam Holewinski
• 金额: $ 60.16万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1944834&HistoricalAwards=false
• 关键词: CAREER; Understanding; Bifunctionality; Organic; Electro

Renewable electrical energy from sources such as wind farms, photovolataic devices, and hydroelectric power can be used to carry out a wide range of chemical reactions important for fuel cells, wastewater treatment, sensors, and chemical manufacturing. Currently, the energy for those reactions is derived primarily from fossil fuels, but renewable electricity offers opportunities to secure our nation's energy future while dramatically decreasing environmental impacts. The project will develop and apply new analytical tools to understand the molecular-level processes needed to make electrochemical reactions efficient. Focus will be placed on understanding ways to use electricity and the oxygen in water to directly convert methanol into commodity chemicals such as formic acid and formaldehyde. The same tools can be applied to the design of methanol fuel cells for energy generation. Insights from the methanol studies will provide a framework for applying electrochemical catalysis to a wide range of organic molecules. The research will be integrated with educational and outreach activities, including an "Energy Academy" program with a regional high-school. Organic electro-oxidation reactions are critical to applications in wastewater treatment, sensing, distributed-scale chemical synthesis, and a multitude of direct-organic fuel cells. Many of these technologies can be built around an interconnected network of single-carbon molecule chemistries involving oxidation of methanol, formaldehyde, formic acid and carbon monoxide. A role for "bifunctional" catalysis - in which one catalyst component selectively activates the organic and the other selectively activates water to form reactive oxygen species - has been widely promoted in the electro-oxidation literature, as well as other areas of catalysis. This project seeks to classify and rationalize the operative mechanisms (bifunctional or otherwise) of two-component electro-oxidation catalysts, and to demonstrate design principles for controlling partial or total oxidation of small organic molecules. An analytical platform, recently developed by the principal investigator, will be used to perform kinetic measurements on well-defined bimetallic nanostructures during rapid bulk electrolysis in flow. The system also forms the basis for the first true liquid electrochemical implementation of steady-state isotope-transient kinetic analysis, permitting direct measurement of product-specific active-site coverages (observed via surface isotope exchange during an otherwise-steady-state reaction) using online electrochemical mass spectrometry. Further insight will be leveraged from top-atomic layer surface analysis by low-energy ion scattering and other auxiliary characterization methods including in-situ infrared spectroscopy and electron microscopy of materials in order to understand the mechanistic pathways governing bifunctional oxidation, and use that knowledge to design new catalytic materials. Critical questions to be answered relate to the determination of the nature of the active sites (e.g. whether carbon-oxygen coupling steps happen at interfaces as opposed to spillover phenomena), their distribution, and their resulting interactions (e.g. how altering one functional component may inadvertently influence the other), with the ultimate goal to rationally control the activity, selectivity, and stability of the electrocatalysts.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.

来自风力发电场、光伏发电设备和水力发电等来源的可再生电能可用于进行对燃料电池、废水处理、传感器和化学制造重要的广泛的化学反应。目前，这些反应的能源主要来自化石燃料，但可再生电力提供了机会，以确保我们国家的能源未来，同时大大减少对环境的影响。该项目将开发和应用新的分析工具，以了解使电化学反应有效所需的分子水平过程。重点将放在了解如何利用电力和水中的氧气将甲醇直接转化为甲酸和甲醛等商品化学品。 同样的工具可以应用于设计用于能量产生的甲醇燃料电池。 从甲醇研究的见解将提供一个框架，电化学催化应用于广泛的有机分子。 这项研究将与教育和推广活动相结合，包括与一所地区高中合作的“能源学院”项目。有机电氧化反应对于废水处理、传感、分布式化学合成和众多直接有机燃料电池的应用至关重要。这些技术中的许多可以围绕单碳分子化学的互连网络构建，包括甲醇，甲醛，甲酸和一氧化碳的氧化。“双功能”催化的作用-其中一种催化剂组分选择性地活化有机物，另一种选择性地活化水以形成活性氧物质-已经在电氧化文献以及催化的其他领域中得到广泛推广。本项目旨在对双组分电氧化催化剂的操作机制（双功能或其他）进行分类和合理化，并展示控制有机小分子部分或全部氧化的设计原理。一个分析平台，最近开发的主要研究者，将被用来进行动力学测量在快速批量电解流动过程中定义良好的纳米结构。该系统还形成了稳态同位素瞬态动力学分析的第一个真正的液体电化学实施的基础，允许使用在线电化学质谱法直接测量产品特定的活性位点覆盖率（通过表面同位素交换在否则稳态反应期间观察到）。通过低能离子散射和其他辅助表征方法，包括材料的原位红外光谱和电子显微镜，将从顶部原子层表面分析中获得进一步的见解，以了解双功能氧化的机制途径，并利用这些知识设计新的催化材料。 需要回答的关键问题涉及活性部位的性质的确定（例如，碳-氧耦合步骤是否发生在界面上，而不是溢出现象），它们的分布，以及它们产生的相互作用（例如，改变一种功能组分如何可能无意中影响另一种），最终目标是合理地控制活性，选择性，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Dynamic electrocatalysis: Examining resonant catalytic rate enhancement under oscillating electrochemical potential

动态电催化：检查振荡电化学势下共振催化速率的增强

• DOI: 10.1016/j.checat.2022.09.002
• 发表时间: 2022
• 期刊: Chem Catalysis
• 作者: Baz, Adam;Lyons, Mason;Holewinski, Adam
• 通讯作者: Holewinski, Adam

Predicting macro-kinetic observables in electrocatalysis using the generalized degree of rate control

• DOI: 10.1016/j.jcat.2021.03.014
• 发表时间: 2021-04-26
• 期刊: JOURNAL OF CATALYSIS
• 影响因子: 7.3
• 作者: Baz, Adam;Holewinski, Adam
• 通讯作者: Holewinski, Adam