ECO-CBET: Electrodeless Electrochemical Valorization of Lignin

以植物为基础的材料，也被称为生物质，是一种能源丰富的物质，几十年来一直被认为是一种最终由大气二氧化碳形成的可再生资源。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。在这项研究项目中，研究人员将开发将植物物质转化为化学物质的基本过程，这些化学物质具有类似于从石油原料中提取的用途。可再生电力将被用来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。这些自由电子是化学反应的，会启动木质素的分解过程。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用作其他化学品和材料的原料。这项研究项目还包括中学生参加“研究一天”的活动，这样他们就可以展望未来的自己在大学和STEM的职业道路上。本科生将在教员调查人员的指导下参加国家项目，如EPA P3可持续设计大赛和NAE大挑战大赛。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将等离子体-液体界面概念化为一种受控手段，在没有固体电极或故意添加电解液的情况下促进选择性有机氧化还原反应。其目的是描述与有机氧化还原反应相关的热力学、动力学和在有或没有电催化剂的情况下，由等离子体-液体界面驱动的液体中的传递。其结果将是建立一个更广泛的框架，以了解转化率、反应速率、产率和选择性对等离子体工艺变量、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物种以及液体侧的还原电位上。研究人员将阐明活性氧和氮物种在等离子体-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断裂。在这些研究的基础上，研究人员将开发新的氢原子转移电催化剂的设计原则，这种催化剂可以用于介导由等离子体-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。这项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运行条件的依赖。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。

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.