CAS: Design and Mechanistic Understanding of Emerging Metal Chalcogenide Electrocatalysts for Selective Two-Electron Oxygen Reduction

在化学系化学催化计划的支持下，威斯康星大学麦迪逊分校的宋进教授和J·R·施密特教授将设计和研究新的选择性和稳定性的电催化剂，以利用电力从氧气中生成过氧化氢(H2O2)。双氧水是一种绿色化学氧化剂，在工业和环境领域有着广泛的应用。与目前集中式的过氧化氢化学生产相比，通过直接还原氧气的电化学生产过氧化氢将降低成本和能源消耗，并实现利用可再生电力的分布式生产。为此，最近在开发用于过氧化氢电合成的电催化剂方面取得了重大进展。尽管如此，这些催化剂的性能和长期稳定性仍有待提高。这个合作项目将建立在团队先前成就的基础上，设计、研究并增强一系列新的金属硫化物电催化剂。对使用新兴的金属硫化物电催化剂进行选择性氧还原的科学认识将使产生过氧化氢的新方法成为可能，用于环境中的各种应用，包括水处理，以及可持续发展，特别是用于替代化学生产，例如，以过氧化氢为氧化剂。在这个项目中，威斯康星大学麦迪逊分校的金/施密特合作团队将把理论和实验结合起来，设计和研究新兴的金属硫化物电催化剂，以及影响它们在酸性和中性溶液中2E-电还原氧气产生过氧化氢的催化稳定性、活性和选择性的因素。这种选择性的2E-氧还原反应(ORR)电催化剂可以促进H_2O_2的分散电化学生产，H_2O_2是一种环境友好的氧化剂，应用广泛。具体地说，将从实验和理论上研究新型层状金属硫化物电催化剂，以获得更好的2E-ORR的选择性、活性和稳定性，特别是在中性溶液中。建立微观动力学模型的密度泛函理论计算将直接与多种类型的操纵态研究相联系，目的是识别关键的反应中间体并了解催化机理。将进行系统的电化学研究和分子动力学模拟，然后进行现场测量，以帮助阐明阳离子和溶剂在增强电催化剂方面的作用。该项目有可能促进高效、分散的电化学生产过氧化氢，从而在环境和可持续性化学方面产生广泛的科学影响。本文开发的机械论见解和操作方法也将为解决使用更多不同金属化合物的选择性电催化中日益复杂的挑战奠定基础。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。

With the support of the Chemical Catalysis Program in the Division of Chemistry, Professors Song Jin and J. R. Schmidt of the University of Wisconsin-Madison will design and study new selective and stable electrocatalysts to produce hydrogen peroxide (H2O2) from oxygen using electricity. Hydrogen peroxide is a green chemical oxidant with many industrial and environmental applications. In contrast to current centralized chemical production of H2O2, electrochemical production of H2O2 by direct reduction of oxygen would reduce cost and energy consumption, and enable distributed production using renewable electricity. To this end, there have been significant recent advances in the development of electrocatalysts for H2O2 electrosynthesis. Nonetheless, the performance of these catalysts and their long-term stability still need improvement. This collaborative project will build on the team’s prior accomplishments to design, investigate and then enhance a series of new metal chalcogenide electrocatalysts. The scientific understanding of selective oxygen reduction using emerging metal chalcogenide electrocatalysts will enable new approaches for the generation of H2O2 for myriad applications in environment, including water treatment, and in sustainability, particularly for alternative chemical production, for example, with H2O2 as oxidant. Concerted efforts on educational outreach to K-12 students and fostering a more diverse scientific community will also be undertaken.In this project, the collaborative Jin/Schmidt team at the University of Wisconsin-Madison will combine theory and experiment to design and investigate emerging metal chalcogenide electrocatalysts and the factors that govern their catalytic stability, activity, selectivity for 2e- electroreduction of oxygen to produce H2O2 in acidic and neutral solutions. Such selective 2e- oxygen reduction reaction (ORR) electrocatalysts can facilitate decentralized electrochemical production of H2O2, an environmentally benign oxidant with diverse applications. Specifically, new layered metal chalcogenide electrocatalysts will be investigated experimentally and theoretically to achieve better selectivity, activity and stability for 2e– ORR, especially in neutral solutions. Density functional theory calculations to develop microkinetic models will be directly connected with multiple types of operando studies with the aim of identifying key reaction intermediates and understanding catalytic mechanism. Systematic electrochemical studies and molecular dynamics simulations followed by in situ measurements will be undertaken to help elucidate the role of cations and solvents in enhancing the electrocatalysts. This project has the potential to facilitate the efficient decentralized electrochemical production of H2O2 and in so doing have broad scientific impact in environmental and sustainability chemistry. The mechanistic insights and operando approaches developed herein will also lay the groundwork for addressing increasingly complex challenges in selective electrocatalysis using more diverse metal compounds.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.