CAREER: Photocatalytic Optical Fibers

由于光可以自由地收集或有效地产生，因此用光而不是热来驱动化学转化可以比传统的化学生产方法具有显着的优势。然而，在将这些主要是学术性的研究成果推广到工业应用所需的规模方面仍然存在挑战，限制了更安全和更温和的化学加工条件对社会的好处。限制光化学方法的可扩展性的一个重要因素是，虽然原料的高光吸收率对于反应效率是期望的，但它也限制了光穿透到反应介质中的深度。常用的光催化剂也可能非常昂贵，并且最终产品中的残留催化剂杂质通常导致变色或降解。为了解决这些限制，这个CAREER项目将研究使用光催化剂涂层光纤将光引导到反应堆容器中。如果成功，拟议的工作将奠定科学基础，以促进现代光化学在工业规模上的实施，并增强学术光反应工程创新的影响。将光催化剂固定在光纤上有望提高光穿透性和催化过程的效率。由于催化剂是固定的，不会随着反应器进料连续加入，因此所提出的方法将提高工艺经济性，并将提供一种制造原始小分子和不含催化剂杂质的聚合物的途径。消除这些杂质对于生物医学和电子应用中的高纯度化学品的合成是重要的，其中痕量金属可以引入毒性或对器件性能有害。这些研究计划有可能加速大规模实施现代和温和的光化学，并通过帮助弥合农业-工业鸿沟而造福社会。教育和外联活动也将受益于将发展的密切的大学与行业联系，通过实地考察和与行业领导的小组讨论，将本科生和研究生与潜在雇主联系起来。此外，该项目将开发和分发廉价的聚合物科学实验室套件，通过改善获得高质量STEM教育体验的机会，使服务不足的初中和高中学生受益。该CAREER项目将提供将现代光化学的学术进步转化为大规模工业应用所需的基础工程知识。本研究计划的目标是确定有机光氧化还原催化剂的关键化学结构-性质关系，使表面接枝到固定化基材而不影响催化活性。通过研究一系列控制光纤倏逝场的方法，光纤表面拴系的催化剂随后将在分批和连续流反应器系统中作为非均相光催化剂进行测试。催化剂表面密度将通过表面单层接枝和使用瓶刷聚合物系链的组合来控制。一旦确定了最佳的纤维单元间距和分布，工艺生产量和可扩展性将不再受光吸收的限制，而是完全受反应器尺寸的限制。通过将光引入反应器，将避免Beer-Lambert吸收限制，以提供高度可扩展的连续通量方法。由于光催化剂被固定在反应器内（而不是连续添加），它可以被回收用于多个反应;此外，最终的化学产品将不含催化剂杂质，这是许多制药和电子化学产品所必需的条件。从教育和推广的角度来看，该计划将通过形成大学实体，农村学校和工业合作伙伴之间的联盟，广泛影响所有年龄和背景的学生。首席研究员将通过实地考察和与行业领导的小组讨论增加本科生和研究生与潜在雇主之间的界面。此外，该计划将试点并向中学生分发廉价的聚合物科学实验室套件，以改善他们获得优质STEM教育的机会，从而使服务不足的初中和高中学生受益。最后，有针对性的社区外展活动将促进社会经济困难学生的大学入学，同时向非技术受众传达科学原理以及可持续发展和塑料废物回收的重要性。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。

Because light can be collected freely or produced efficiently, driving chemical transformations with light instead of heat can have significant advantages over traditional chemical production methods. However, challenges remain in bringing these mostly academic findings to the scale necessary for industrial adoption, limiting the benefits to society that would result from safer and milder chemical processing conditions. An important factor in restricting the scalability of photochemical processes is that while high light absorptivity of the feedstocks is desirable for reaction efficiency, it also limits light penetration depth into the reaction medium. Commonly used photocatalysts can also be prohibitively expensive, and residual catalyst impurities in the final products often leads to discoloration or degradation. To address these limitations, this CAREER project will study the use of photocatalyst-coated optical fibers to guide light into the reactor vessels. If successful, the proposed work will lay the scientific foundations to facilitate the implementation of modern photochemistry on an industrial scale and enhance the impact of academic photo-reaction engineering innovations. Immobilizing photocatalysts on optical fibers is anticipated to improve light-penetration and efficiency of the catalytic process. Because the catalysts are immobilized and will not be added continuously with the reactor feed, the proposed approach will improve the process economics and will provide a path to manufacturing both pristine small molecules and polymers free of catalyst impurities. Eliminating such impurities is of importance for synthesis of high purity chemicals in biomedical and electronic applications where trace metals can introduce toxicity or be detrimental to device performance. The research plans have the potential to accelerate the implementation of modern and mild photochemistries on large scales and benefit society by helping to bridge the academia-industry divide. Education and outreach activities will also benefit from the close academia-industry ties to be developed, connecting undergraduate and graduate students and potential employers through field trips and panel discussions with industry leadership. Further, this program will develop and distribute inexpensive polymer science laboratory kits that will benefit underserved middle and high school students by improving access to a quality STEM education experience.This CAREER project will provide the fundamental engineering knowledge needed to translate academic advances in modern photochemistry to large-scale industrial applications. The objectives of this research program are to identify critical chemical structure-property relationships for organic photoredox catalysts that will enable surface-grafting to immobilizing substrates without affecting catalytic activity. By investigating a range of approaches to control the optical fiber evanescent field, optical fiber surface-tethered catalysts will subsequently be tested as heterogeneous photocatalysts in both batch and continuous-flow reactor systems. Catalyst surface density will be controlled through a combination of surface monolayer grafting and the use of bottlebrush polymer tethers. Once an optimal fiber unit spacing and distribution is identified, process throughput and scalability will no longer limited by light absorption, but exclusively by the size of the reactor. By bringing light into the reactor, Beer-Lambert absorption limitations will be circumvented to provide a highly scalable continuous throughput methodology. Because the photocatalyst is immobilized within the reactor (and not continuously added), it can be recycled for multiple reactions; furthermore, the final chemical product will be free of catalyst impurities, a condition necessary in many pharmaceutical and electronics chemical products. From an educational and outreach perspective, this program will broadly impact students of all ages and backgrounds by forming a coalition between university entities, rural schools, and industrial partners. The principal investigator will increase interfaces between undergraduate and graduate students and potential employers through field trips and panel discussions with industry leadership. Further, this program will pilot and distribute inexpensive at-cost polymer science laboratory kits to secondary students to benefit underserved middle and high school students by improving their access to quality STEM education. Finally, targeted community outreach events will promote university enrollment of socioeconomically challenged students while communicating scientific principles and the importance of sustainability and plastic waste recycling to non-technical audiences.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.