ERASE-PFAS: Collaborative Research: Nickel and Palladium Single-Atom Electrocatalysts for Selective Capture and Destruction of PFAS in Complex Water Matrices

全氟和多氟烷基物质（PFAS）是一组已广泛使用数十年的化学品。作为许多消费品中的添加剂，PFAS具有许多理想的特性，包括优异的耐化学性。然而，这种性质使得它们很难使用当前的处理工艺从水中去除。化学稳定性也使PFAS在环境中持久存在，对人类和生态健康造成重大影响。电化学氧化法是一种很有前途的处理PFAS的方法。科学家和工程师一直在探索各种策略来提高性能，包括采用纳米技术启用催化剂。然而，这种方法通常需要昂贵的金属，并且在含有各种其他有机化合物的水中选择性破坏PFAS一直具有挑战性。这项研究通过开发下一代催化剂来解决这些缺点，即使水中含有许多其他化合物，催化剂也可以选择性地与PFAS结合并破坏PFAS。这一目标将通过操纵钯（Pd）和镍（Ni）催化剂以原子分散来实现，这一过程称为“单原子催化”（SAC）。SAC是缩小材料尺寸的理论极限，代表了超越纳米技术的科学进步。该研究项目的成果将包括开发实验室规模的原型SAC电化学反应器，并使用PFAS污染水进行测试。研究结果将通过报告、科学期刊、会议和讲座进行传播。该项目将培训两所大学的研究生和本科生在高度合作的环境下进行跨学科研究。高中生将通过暑期研究实习和推广课程招募，提高科学素养和发展国家的STEM劳动力。拟议项目的总体目标是开发一种创新的电催化过程，可以氧化破坏复杂的水基质中的PFAS，以产生良性的最终产品。该项目是探索SAC -材料缩小的理论极限-作为目标电催化剂结构以实现PFAS的高选择性和高效阳极破坏的首批研究之一。本研究的重点是Pd和Ni催化剂的基础上，他们的证明性能PFAS降解纳米尺度。SAC配置具有优于现有催化技术的许多优点。SAC允许可调的金属-配体相互作用和配位环境，这对于i）金属催化中心与PFAS的官能团的选择性结合和ii）从PFAS到阳极的直接电子转移是必不可少的。此外，SAC的原材料消耗极低和低成本合成程序减轻或可能消除使用贵金属如Pd时的成本问题。最后，SAC可能比金属团簇稳定得多，这是反应堆实施的一个重要考虑因素。该研究基于以下基本假设：SAC结构消除了金属晶体纳米团簇中固有的金属-金属相互作用，从而最大限度地提高了PFAS降解动力学。这一假设将通过使用最先进的EXASF、XANES、HAADF-STEM和原位FTIR技术表征合成材料来进行测试。将使用先进的化学分析技术来识别反应产物，以关联材料特性和PFAS降解途径。该项目的成功完成将促进对SAC合成，SAC驱动的电催化的理解，并建立PFAS销毁的新策略。该合作团队由两个研究小组组成，两个研究小组在两个机构与免费专业将提供独特的多学科，合作培训的机会，参与研究生和本科生。将为高中学生和教师开设以氟化学和电化学为重点的暑期课程。该项目团队致力于招募代表性不足的学生参加所有推广和培训活动，以使国家的STEM劳动力多样化，并促进研究和学习的包容性文化。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Per- and polyfluorinated alkyl substances (PFAS) are a group of chemicals that have been widely used for decades. As additives in numerous consumer products, PFAS have many desirable properties, including exceptional chemical resistance. However, this property makes them very difficult to remove from water using current treatment processes. The chemical stability also makes PFAS persist in the environment, causing significant concerns for human and ecological health. One promising way to treat PFAS in water to benign end products is electrochemical oxidation. Scientists and engineers have been exploring various strategies to enhance performance, including employing nanotechnology enabled catalysts. However, expensive metals are often required in this approach, and selective destruction of PFAS in the water that contains various other organic compounds has been challenging. The proposed research addresses these drawbacks through the development of next-generation catalysts that can selectively bind with and destroy PFAS even when the water contains many other compounds. This goal will be pursued by manipulating palladium (Pd) and nickel (Ni) catalysts to be atomically dispersed, a process known as ‘single-atom catalysis’ (SAC). SAC is the theoretical limit of downsizing materials, and represents the state-of-science advancement beyond nanotechnology. The outcomes of this research project will include development of a laboratory-scale prototype SAC electrochemical reactor tested with PFAS contaminated water. Results will be disseminated through reports, scientific journals, conferences, and lectures. This project will train graduate and undergraduate students at two universities to perform interdisciplinary research under a highly collaborative environment. High school students will be recruited via summer research internship and outreach courses, increasing scientific literacy and developing the Nation’s STEM workforce. The overarching objective of the proposed project is to develop an innovative electrocatalytic process that can oxidatively destroy PFAS in complex water matrices to benign end products. This project is one of the first studies to explore SAC – the theoretical limit of material downsizing – as the target electrocatalyst architecture to achieve highly selective and efficient anodic destruction of PFAS. The focus of this research is on Pd and Ni catalysts based on their proven performance for PFAS degradation at nano-scale. The SAC configuration has numerous advantages over existing catalysis technology. SAC allows tunable metal-ligand interactions and coordination environments that are essential for i) selective binding of the metal catalytic centers to functional groups of PFAS, and ii) direct electron transfer from PFAS to the anode. In addition, extremely low consumption of raw materials and low-cost synthesis procedures for SAC alleviate or possibly eliminate cost concerns when using noble metals like Pd. Finally, SACs are likely much more stable than metallic clusters, an important consideration for reactor implementation. The research is based on the underlying hypothesis that SAC architecture eliminates metal-metal interactions that are inherent in metallic, crystalline nanoclusters, resulting in PFAS degradation kinetics enhanced to the maximum extent possible. This hypothesis will be tested through characterization of the synthesized materials using state-of-the-science EXASF, XANES, HAADF-STEM, and in-situ FTIR techniques. Reaction products will be identified using advanced chemical analytical techniques to correlate material property and PFAS degradation pathways. The successful completion of this project will advance understanding of SAC synthesis, SAC-driven electrocatalysis, and establish new strategies for PFAS destruction. The collaborative team consisting of two research groups at two institutions with complimentary specialties will provide unique multidisciplinary, collaborative training opportunities to participating graduate and undergraduate students. Summer courses focusing on fluorine chemistry and electrochemistry will be developed for high school students and teachers. The project team is committed to recruiting underrepresented students for all outreach and training activities to diversify the Nation’s STEM workforce and promote an inclusive culture for research and learning.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.