Collaborative Proposal: NSF-DFG Echem: Understanding the Mechanism of Urea Oxidation on Nickel-Based Electrocatalysts

尿素是哺乳动物新陈代谢中常见的高氮化学废物，也是化肥的主要成分，农业径流和城市污水对水资源构成严重威胁。去除多余尿素的一种有希望的方法是将其电化学氧化，产生无害的化合物。尿素去除过程也可用于发电和生产燃料电池所需的氢气。因此，通过将有害的废物转化为社会、工业和环境的效益，电化学尿素去除显示出强大的潜力作为一种变革性技术。该项目汇集了来自美国和德国的研究人员，将实验和理论方法的协同结合应用于电化学去除水中尿素的研究。特别是，该项目寻求对开发可行的尿素去除技术所需的催化尿素氧化的基本了解。有效的尿素去除系统是大量技术应用的关键，包括市政和农业废水处理、化肥径流修复、氨合成、制氢和发电。该项目的其他好处将包括劳动力发展和对代表性不足的小学生的教育推广。这些努力将促进STEM领域的多样性增加，这是德国和美国之间的一个学生交流项目，并提高普通公众的科学素养。该研究项目的目标是在跨越分子和设备水平的实验和理论研究的基础上，发展关于镍基催化剂上电化学尿素去除的全面知识。将通过密度泛函理论计算、振动和电子共振和频率谱以及反应速率和产物分布的电化学测量来研究电化学尿素去除。特别关注氧化镍电极的活性形式，因为它存在于不同的相和氧化状态，取决于电极的电位和历史，如老化和制备方法。这种电化学、光谱和计算相结合的方法提供了与催化剂结构变化相关的见解，以及它们如何影响镍、镍铁和镍铬催化剂的尿素反应机理、反应性和有效性。这项研究的结果将极大地促进对电化学尿素去除的科学理解--人们对此知之甚少--并在更广泛的电催化领域奠定基础，涉及氧化物表面和作为整体反应机制一部分发生氧化状态变化的表面的电化学反应。这项研究的成功完成将通过处理废水和农业径流的可持续方法造福社会，这些方法将减少对供水系统的需求并增强海洋生态系统的生物多样性。该项目是通过“NSF-DFG在电合成和电催化方面的牵头机构活动(NSF-DFG eChem)”机会获得的，这是一个涉及国家科学基金会和德国科学基金会(DFG)的合作征集活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Urea – a common high-nitrogen chemical waste product of mammalian metabolism, and a major component of fertilizer – poses significant threat to water resources from agricultural run-off and municipal wastewater. A promising means for removing excess urea is to oxidize it electrochemically to produce produce harmless compounds. Urea removal processes can also be used to generate electricity and to produce hydrogen for fuel cells. Electrochemical urea removal therefore exhibits strong potential as a transformative technology by converting a harmful waste product to the benefit of society, industry, and the environment. The project brings together researchers from the United States and Germany to apply a synergistic blend of experimental and theoretical methods to the study of electrochemical urea removal from water. In particular, the project seeks fundamental understanding of catalytic urea oxidation that is needed to develop feasible urea removal technologies. Effective urea removal systems are key to a large number of technological applications including municipal and agricultural wastewater treatment, remediation of fertilizer run-off, ammonia synthesis, hydrogen production, and electricity generation. Other benefits from this project will include workforce development and educational outreach to underrepresented grade-school students. These efforts will promote increased diversity in STEM fields, a student exchange program between Germany and the US, and improved scientific literacy of the general public.The goal of this research project is to develop comprehensive knowledge of electrochemical urea removal over nickel-based catalysts, based on experimental and theoretical research spanning molecular and device levels. Electrochemical urea removal will be studied by density functional theory calculations, vibrationally and electronically resonant sum frequency spectroscopy, and electrochemical measurements of reaction rate and product distributions. Particular attention will be paid to the active form of the nickel oxide electrode as it exists in different phases and oxidation states depending on electrode potential and history, such as aging and preparation method. This combined electrochemical, spectroscopic, and computational approach provides insight related to catalyst structural changes and how they affect the urea reaction mechanism, reactivity, and effectiveness of nickel, nickel-iron, and nickel-chromium catalysts. The outcomes of this research will greatly advance the scientific understanding of electrochemical urea removal -- about which little is known -- and establish a foundation in the wider field of electrocatalysis regarding electrochemical reactions on oxide surfaces and on surfaces that undergo a change in oxidation state as part of the overall reaction mechanism. Successful completion of this research will benefit society through sustainable methods for treating wastewater and agricultural run-off that will reduce demand on water supply systems and enhance the biodiversity of marine ecosystems. This project was awarded through the “NSF-DFG Lead Agency Activity in Electrosynthesis and Electrocatalysis (NSF-DFG EChem)" opportunity, a collaborative solicitation that involves the National Science Foundation and Deutsche Forschungsgemeinschaft (DFG).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.