Outer coordination sphere optimization of electrocatalytic CO2 reduction

能源供应的安全性、可持续性和环境后果是现代社会全球关注的问题。大自然优化了光合作用的机制，通过将二氧化碳和水转化为碳水化合物燃料来吸收和收获太阳能。然而，将二氧化碳和水——地球上最普遍的化学物质——转化为可持续的燃料来源这一看似简单的过程，仍然是当今科学面临的重大挑战之一。在这个项目中，马萨诸塞大学波士顿分校的Rochford博士向大自然学习，并开发了下一代分子催化剂，可以模拟光合作用，有效地将二氧化碳和水转化为有用的燃料。正如我们在宏观世界中受到自身环境的强烈影响一样，二氧化碳和水的行为和性质在分子尺度上也对其局部环境非常敏感。罗奇福德博士和他的学生们受到光合作用的启发，利用“自组装”技术，利用二氧化碳和水对环境的敏感性，优化其可持续转化为燃料。这项来自美国国家科学基金会化学部化学催化项目的资助丰富了许多马萨诸塞大学波士顿分校学生的本科和研究生经历，并对马萨诸塞大学波士顿分校的研究组合产生了重大的积极影响。该项目代表了一种新的电催化二氧化碳还原方法，通过设计和合成具有工程设计的第二配位球和外部配位球的分子催化剂，提供对产物形成（一氧化碳、甲酸、氢气）的选择性控制。针对第一排Mn(I)基过渡金属催化剂，通过调整配体的第二和外部配位球，优化过渡态能量以促进质子耦合电子转移，从而降低关键速率决定步骤的活化能，从而最大化催化剂的转换频率，并降低所需的最小过电位，从而实现了显著的智力优势。Rochford博士和他的学生开发了从合成到自组装的尖端催化剂设计方法，并结合了定制的电化学分析，这对使用纳米结构和电活性表面的许多研究领域产生了影响。这一领域的成功使化学催化界能够更好地设计、控制和优化第一排过渡金属催化剂，以在可接近的过电位下选择性地进行二氧化碳转化。Rochford博士大力倡导对年轻学者进行有关二氧化碳、可再生能源替代品和可再生能源技术进步的环境影响的教育。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。

The security of an energy supply, its sustainability and environmental consequences are global concerns in modern society. Nature has optimized the mechanism of photosynthesis to absorb and harvest solar energy by transforming carbon dioxide and water into carbohydrate fuels. Yet, this apparently simple transformation of carbon dioxide and water - the most ubiquitous chemicals on earth - to a sustainable fuel source still represents one of the grand challenges of science today. In this project, Dr. Rochford of University of Massachusetts Boston learns from nature and develops a next generation of molecular catalysts that can mimic photosynthesis to efficiently transform carbon dioxide and water into useful fuels. Just as we are strongly influenced by our own environment in a macroscopic world, the behavior and properties of carbon dioxide and water are also very sensitive to their local environment at a molecular scale. Dr. Rochford and his students utilize "self-assembly" techniques, inspired by photosynthesis, to leverage the environmental sensitivity of carbon dioxide and water to optimize their sustainable transformation into fuels. This grant from the Chemical Catalysis Program of the NSF Chemistry Division enriches the undergraduate and graduate experiences of many UMass Boston students and has a major positive impact on the UMass Boston research portfolio. This project represents a novel approach to electrocatalytic carbon dioxide reduction through the design and synthesis of molecular catalysts with engineered second- and outer-coordination spheres providing selective control over product formation (carbon monoxide vs. formic acid vs. hydrogen gas). Significant intellectual merit is achieved by targeting first-row Mn(I)-based transition metal catalysts whereby tailoring the second- and outer-coordination sphere of the ligand, transition-state energies is optimized to promote proton-coupled electron transfer, thus reducing activation energies for critical rate-determining steps to maximize catalyst turnover frequencies, and reduce the minimum required overpotential. Dr. Rochford and his students develop cutting-edge catalyst design methods, from synthesis to self-assembly, combined with tailored electrochemical analyses, which impacts on a host of research areas that employ nanostructured and electroactive surfaces. Success in this area informs the chemical catalysis community to better design, control and optimize first-row transition metal catalysts for selective carbon dioxide conversion at accessible overpotentials. Dr. Rochford is a strong advocate of education for young scholars regarding the environmental impacts of carbon dioxide, renewable energy alternatives, and advances in renewable energy technologies.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.