Imidazolium Functionalized Transition Metal Phosphide Catalysts for Electrochemical Carbon dioxide Conversion to Ethanol

电化学反应是一种很有前途的将温室气体二氧化碳转化为有价值的化工产品的技术。当由风能或太阳能等可持续电力提供动力时，电化学二氧化碳还原反应（eCO2RR）技术可能为化学制造提供负碳排放的途径。然而，由于依赖昂贵的贵金属催化剂材料，电催化反应中的能量损失，二氧化碳转化为目标产物的效率低下，以及二氧化碳捕获和转移到工作催化剂表面的速度较低，目前的eCO2RR技术受到限制。该项目旨在通过研究开发一种有效的催化系统来解决这些技术差距，该系统基于一种低成本的过渡金属磷化物（TMPs）类材料，这种材料用一种化学化合物（咪唑（Im））修饰，可以增强二氧化碳向催化剂表面的转移。这两个组成部分共同促进了废二氧化碳的捕获和转化为乙醇，用于下游燃料和化学应用。除了技术方面，该项目还支持教育和研究项目，培养与清洁能源和可持续发展相关技术的未来领导者。该项目建立在咪唑功能化TMP催化剂可以调整表面金属原子的电子性质以促进碳-碳偶联以实现高速率乙醇生产的假设之上。该项目采用系统的方法，结合实验和计算研究来设计和验证Im-TMP催化系统的不同组成部分，并确定在活性、选择性和稳定性中起关键作用的关键因素。该项目利用现有的合作关系，旨在通过电化学测试和分析的定向实验努力，建立一种新的催化系统，用于从二氧化碳中电合成乙醇。各种纳米结构的TMP纳米粒子，具有MP （M：过渡金属）的化学计量学和它们的非官能化结构，将被表征和评价。材料组合的选择是基于研究人员的初步研究结果，该研究表明咪唑功能化磷化钼（Im-MoP）纳米颗粒作为一个统一的系统来生产乙醇。这个项目的关键目标是结合前沿的原位、非原位、原子和分子尺度实验与DFT计算，以确定TMP表面原子的电子和结构特性及其与咪唑的相互作用。这些信息将用于发展Im-TMP催化剂的电子-结构-性能关系。从这项研究中获得的见解将为开发其他常见电催化过程（如固氮、氧还原和析氧反应）的先进材料建立新的方法，在这些过程中，用有机分子功能化催化剂的表面可能会显示出类似的好处。从教育和推广的角度来看，该项目将与研究人员校园的本科研究教育联合计划（PURE）相结合。此外，研究人员将与伊丽莎白市立大学（HBCU和公共学士学位机构）合作，为各种电化学应用带来与材料设计、合成和表征相关的知识，并为来自弱势群体的学生提供研究机会，鼓励他们攻读能源科学的高级学位。该项目还将通过沉浸式的暑期研究体验，为来自芝加哥地区学校的代表性不足的高中生群体提供动手研究的机会。该奖项反映了美国国家科学基金会的法定使命，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。

Electrochemical reaction is a promising technology for converting the waste greenhouse gas, carbon dioxide (CO2), to valuable chemical products. When powered by sustainable electricity from sources such as wind power or solar energy, electrochemical CO2 reduction reaction (eCO2RR) technology potentially offers a negative carbon emission route to chemical manufacturing. Current eCO2RR technology is limited, however, by dependence on expensive noble metal catalyst materials, energy losses in the electrocatalytic reactions, inefficient conversion of CO2 to targeted products, and low rates of CO2 capture and transfer to the working catalyst surface. The project addresses those technology gaps through research aimed at developing an effective catalytic system based on a low-cost transition metal phosphide (TMPs) class of materials modified with a chemical compound (imidazolium (Im)) that enhances the transfer of CO2 to the catalyst surface. Together the two components promote the capture and conversion of waste CO2 to ethanol for use in downstream fuel and chemical applications. Beyond the technical aspects, the project supports educational and research programs educating future leaders in technology related to clean energy and sustainability. The project is built on the hypothesis that imidazolium-functionalized TMP catalysts can tailor the electronic properties of surface metal atoms to promote carbon-carbon coupling for high rate ethanol production. The project employs a systematic approach, combining experimental and computational studies to design and validate different components of the Im-TMP catalytic system, and to identify key factors that play crucial roles in activity, selectivity, and stability of the proposed catalytic system. The project exploits existing collaborative relationships with the aim of establishing a novel catalytic system for electrosynthesis of ethanol from CO2 through directed experimental efforts in electrochemical testing and analysis. Various nanostructured TMP nanoparticles, with stoichiometry of MP (M: transition metal)and their Im-functionalized structure, will be characterized and evaluated. The materials combinations are selected based on preliminary results from the investigators’ research showing that imidazolium-functionalized molybdenum phosphide (Im-MoP) nanoparticles work as a unified system to produce ethanol. Crucial to the goal of this project, is the combination of cutting edge in-situ, ex-situ, atomic- and molecular-scale experiments with DFT calculations that will be performed to identify electronic and structural properties of TMP surface atoms and their interactions with imidazolium. This information will be utilized to develop electronic–structural–performance relationships of the Im-TMP catalysts. The insights gained from the research will establish new methods for the development of advanced materials for other common electrocatalytic processes, such as nitrogen fixation, and the oxygen reduction and oxygen evolution reactions, where functionalizing the surface of catalysts with organic molecules may show similar benefits. From the educational and outreach perspectives, the project will interface with the joint initiatives Program for Undergraduate Research Education (PURE) on the investigators’ campus. Additionally, the investigators will collaborate with Elizabeth City State University, a HBCU and public baccalaureate institution, to bring knowledge related to materials design, synthesis, and characterization for various electrochemical applications and provide research opportunities for students coming from under-represented groups, encouraging them to pursue advanced degrees in energy sciences. The project will also provide hands-on research opportunities to underrepresented groups of high-school students from regional Chicago schools through an immersive summer research experience.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.