ECO-CBET: Electrodeless Electrochemical Valorization of Lignin

植物基材料，也被称为生物质，是富含能量的物质，几十年来一直被认为是一种可再生资源，最终形成于大气中的二氧化碳。生物质的生产规模也可以大到足以满足世界对燃料和有机材料的需求。在这个研究项目中，研究人员将开发将植物物质转化为化学物质的基本过程，这种化学物质与来自石油原料的化学物质具有类似的效用。可再生电力将用于将气体激发成等离子体，等离子体是一种含有自由电子的部分电离气体。这些自由电子具有化学活性，并将开始木质素分解过程。木质素是木本植物的一种成分，其分解产物由各种化学物质组成，这些化学物质可用作燃料或其他化学物质和材料的起始原料。这个研究项目还包括中学生参加“研究员一天”活动，这样他们就可以想象自己在大学和STEM职业道路上的未来。本科生将在学院调查人员的指导下参加国家项目，如EPA P3可持续设计竞赛和NAE大挑战竞赛。研究生将获得策划和主持学术会议的经验。该项目的科学目标是概念化等离子体-液体界面作为一种受控手段来促进选择性有机氧化还原反应，而无需固体电极或故意添加电解质。目标是描述由等离子体-液体界面驱动的液体中与有机氧化还原反应相关的热力学、动力学和传输，有和没有电催化剂。结果将是建立一个更广泛的框架来理解转化、反应速率、产率和选择性对等离子体过程变量、电催化剂分子结构和液体介质性质的依赖。具体的研究目标包括确定等离子体性质与等离子体-液体界面反应性的关系。重点将放在研究活性氧和氮的种类和还原电位在液体侧。研究人员将阐明活性氧和活性氮在等离子体-液体界面驱动的有机氧化还原反应选择性中的作用。他们还将使用氢原子转移电催化剂来实现木质素和模型木质素化合物中β - o -4键的选择性氧化和还原切割。基于这些研究，研究人员将开发新的氢原子转移电催化剂的设计原则，该催化剂可用于介导等离子体-液体界面驱动的有机氧化还原反应。最后，研究人员将对等离子体-液体化学转化过程进行技术经济和生命周期评估。这一分析将侧重于大气二氧化碳减排潜力和经济可行性对工艺投入和操作条件的依赖。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。

Plant-based materials, also known as biomass, are energy-rich substances that have been recognized for decades as a renewable resource ultimately formed form atmospheric carbon dioxide. Biomass also can be produced at a scale large enough to meet the world’s fuel and organic material needs. In this research project, the investigators will develop fundamental processes to convert plant matter into chemicals that have similar utility to those derived from petroleum feedstocks. Renewable electricity will be used to excite gasses into plasma, which is a partially ionized gas containing free electrons. These free electrons are chemically reactive and will start a lignin decomposition processes. Lignin is a component of woody plants, and its decomposition products are comprised of various chemicals that can be useful as fuel or as starting materials for other chemicals and materials. This research project also includes middle school students participating in “Researcher for a day” activities, so they can envision their future selves in college and on a STEM career track. Undergraduate students will be mentored by the faculty investigators to compete in national programs such as the EPA P3 Sustainable Design Competition and the NAE Grand Challenges Competition. Graduate students will gain experience in planning and hosting an academic conference.The scientific objective of this project is to conceptualize the plasma-liquid interface as a controlled means to promote selective organic redox reactions without solid electrodes or intentionally added electrolyte. The goal is to describe the thermodynamics, kinetics, and transport associated with organic redox reactions in a liquid driven by a plasma-liquid interface, with and without electrocatalysts. The outcome will be to establish a broader framework to understand the dependence of conversion, reaction rate, yield, and selectivity on plasma process variables, electrocatalyst molecular structure, and liquid medium properties. The specific research aims include determining the relationship of plasma properties to reactivity at the plasma-liquid interface. An emphasis will be placed on studying reactive oxygen and nitrogen species and the reduction potential on the liquid side. The researchers will elucidate the role of reactive oxygen and nitrogen species in the selectivity of organic redox reactions driven by the plasma-liquid interface. They will also use hydrogen atom transfer electrocatalysts to achieve selective oxidation and reductive cleaving of beta-O-4 linkages in lignin and model lignin compounds. Based on these studies the investigators will develop design principles for new hydrogen atom transfer electrocatalysts that can be used to mediate organic redox reactions driven by the plasma-liquid interface. Finally, the researchers will perform a technoeconomic and lifecycle assessment of plasma-liquid chemical conversion processes. This analysis will focus on the dependence of atmospheric carbon dioxide mitigation potential and economic viability on process inputs and operating conditions.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.