Modeling Product Selectivity in Electrocatalytic Carbon Dioxide Reduction Using Scaling Relationships

项目摘要 Wood-Ljugdahl(WL)途径是一种依赖于两种不同二氧化碳还原的CO2固定途径 酶--甲酸脱氢酶(FDH)和一氧化碳脱氢酶(CODH)--最终 通过甲酸盐和一氧化碳将二氧化碳转化为生物质。生物已经成功地进化出催化剂， WL途径中的反应具有显著的活性和选择性，这是令人羡慕的 制药和商品化学品行业，在这些行业中，有效利用二氧化碳作为c1构建块 是可取的。尽管如此，试图为均相电催化设计这些酶的结构模型 二氧化碳减排一直不成功。更全面地了解WL中发现的酶- 途径和更好的二氧化碳还原催化剂的设计将需要更好地理解内在的 性质-催化剂的还原电位(E_1/2)、pKa和酸浓度以及中间体的程度 二次球体效应稳定--直接产物选择性。 为了更好地理解这些酶的性质如何导致不同的选择性，分子 电化学二氧化碳还原反应(CO2RR)的“热力学-动力学标度关系”将为 发展起来的。“标度关系”被定义为热力学变量与动力学变量之间的相关性。 结果，如更替频率或选择性。这些缩放关系将用于确定如何 对可调热力学变量(催化剂E1/2、酸性PKA等)的扰动影响选择性结果。 监测作为这些变量的函数的选择性将使建立选择性模型成为可能。在……里面 此外，我们将确定次级球效应如何通过氢键和 静电相互作用类似于酶活性部位中发现的类似效应。最后，我们的目标是解决如何 电场--越来越多地牵涉到酶的作用机制--改变了 通过研究具有锚定分子二氧化碳还原催化剂的混合电极。 梅耶尔教授和耶鲁大学提供了一个极好的环境，不仅可以进行我提出的 研究，但要成长为一名科学家。我计划在梅耶尔教授的指导下进行的研究 将给我知识来解决广泛的复杂问题。在我的博士后生涯中 在任职期间，我通过演讲和交流来继续发展我的专业技能 写作，继续指导学生，就像我在整个职业生涯中所做的那样，但要以新的视角。 此外，耶鲁大学围绕着我的教职员工，他们在我瞄准的许多领域都有丰富的知识 成为。例如，帕特里克·霍兰德教授在配基设计方面令人难以置信的声誉，以及莎伦·哈姆斯教授- 希弗在PCET理论方面的领导地位无疑将是我提出的分子二氧化碳的有益资源 电还原。在梅耶尔教授和耶鲁大学的指导下，我将继续发展自己的身份 作为一名独立科学家。

Project Summary The Wood-Ljungdahl (WL) pathway is a CO2 fixation pathway that relies on two different CO2 reducing enzymes — formate dehydrogenase (FDH) and carbon monoxide dehydrogenase (CODH) — to ultimately convert CO2 to biomass through formate and carbon monoxide. Biology has successfully evolved catalysts for the reactions in the WL-pathway that feature remarkable activity and selectivity that is envied by the pharmaceutical and commodity chemicals industries, where the efficient utilization of CO2 as a C1 building block is desirable. Despite this, attempts to design structural models of these enzymes for homogenous electrocatalytic CO2 reduction have been unsuccessful. A more comprehensive understanding of the enzymes found in the WL- pathway and the design of better CO2 reduction catalysts will require a better understanding of how the intrinsic properties — reduction potential (E1/2) of the catalyst , pKa and concentration of acid, and degree of intermediate stabilization by secondary sphere effects — direct product selectivity. In order to better understand how the properties of these enzymes lead to disparate selectivity, molecular “thermodynamic-kinetic scaling relationships” for the electrochemical CO2 reduction reaction (CO2RR) will be developed. “Scaling relationships” are defined as a correlation between thermodynamic variables with kinetic outcomes such as turnover frequency or selectivity. These scaling relationships will be used to determine how perturbations to tunable thermodynamic variables (catalyst E1/2, acid pKa, etc.) affect selectivity outcomes. Monitoring the selectivity as a function of these variables will enable the building of a selectivity model. In addition, we will determine how secondary sphere effects alter the selectivity through hydrogen bonding and electrostatic interactions in analogy to similar effects found in enzyme active sites. Last, we aim to address how electric fields — which are increasingly implicated in enzymatic mechanisms of action — alter the selectivity of CO2RR through the study of hybrid electrodes featuring an anchored molecular CO2 reduction catalyst. Prof. Mayer and Yale University have provided an excellent environment to not only conduct my proposed research but to grow as a scientist. The research I am proposing to conduct under the mentorship of Prof. Mayer will give me the knowledge to address a wide range of complex problems. During my burgeoning postdoctoral tenure, I am continuing to develop my professional skills by communicating my work through presentations and writing, and to continue mentoring students as I've done throughout my career but with a new perspective. Additionally, Yale University has surrounded me with faculty that are knowledgeable in many of the areas I aim to be. For example, Prof. Patrick Holland's incredible reputation for ligand design and Prof. Sharon Hammes– Schiffer's leadership in PCET theory will undoubtedly be beneficial resources for my proposed molecular CO2 electroreduction. Under the guidance of Prof. Mayer and Yale University, I will continue to develop my identity as an independent scientist.