CBET: Upconversion Enhanced Visible Light Sensitization of Semiconductor Photocatalysts for Environmental Application

CBET：用于环境应用的半导体光催化剂的上转换增强可见光敏化

• 批准号: 1335934
• 负责人: Jaehong Kim
• 金额: $ 33万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1335934&HistoricalAwards=false
• 关键词: CBET; Upconversion; Enhanced; Visible; Light

CBET 1335934Jaehong KimYale UniversityEnvironmental application of semiconductor photocatalysts as a sustainable technology option has received significant attention over the past few decades with some notable commercial successes. But challenges still remain and are related to its relatively low efficiency of photosensitization by longer-wavelength, lower-energy light that is abundant in the solar spectrum. This project will develop a highly innovative approach of enhancing the visible light susceptibility of semiconductor-based photocatalytic process. This research aims at manipulating light to amplify its frequency via a unique photoluminescence process called upconversion (UC) based on a triplet-triplet annihilation (TTA) mechanism. Through the TTA-UC process, two photons of higher wavelength, which are otherwise wasted, are combined and converted to a single photon with lower wavelength; these upconverted photons are subsequently used to sensitize photocatalysts and to produce reactive oxygen species (ROS) that effectively degrade pollutants and inactivate microorganisms in water. Researchers will employ a pair of organic sensitizers and acceptors that enable a highly efficient visible to visible or blue to UVA upconversion. Researchers will select various chromophore pairs, encapsulate them into microcapsules, and couple them with selected semiconductor photocatalysts. Various photoluminescence and photocatalytic experiments and instrumental analyses will be performed to quantitatively evaluate the properties of this new system including quantum yield, excitation and emission spectra, kinetics of energy transfer process (time-resolved spectra), and ROS production. The material synthesis and system development will be specifically targeted and tested for contaminant degradation and microbial inactivation in water as well as separation and recovery after use.Ensuring access to inexpensive and clean sources of water is one of the greatest global challenges of this century. Advanced materials technology, such as the one developed in this project, offers opportunities to leapfrog over traditional infrastructure-intensive technologies to develop more sustainable approaches in both industrialized and developing countries, as long as cost efficacy is assured and unnecessary collateral impacts are avoided. This project has a great potential to develop solar-based technology that efficiently harvests lower-energy portions of the solar spectrum which is otherwise wasted in any existing photocatalyst-based processes. Researchers expect that UC/photocatalysts with improved solar energy utilization efficiency and capability for easy separation can be readily implemented in various environmental engineering practices including solar photocatalytic disinfection (e.g., implemented using a solar concentrator), advanced oxidation, and photocatalysis. The project aims at achieving this goal through effective integration the photophysics of upconversion, material synthesis, semiconductor photocatalysis, environmental micropollutant control, and disinfection.

CBET 1335934 Jaehong Kim耶鲁大学半导体光催化剂的环境应用作为一种可持续的技术选择在过去的几十年里受到了极大的关注，并取得了一些显着的商业成功。但挑战仍然存在，并且与其相对较低的光敏效率有关，其光敏效率较低，波长较长，能量较低，在太阳光谱中丰富。该项目将开发一种高度创新的方法，以提高基于光催化剂的光催化过程的可见光敏感性。这项研究的目的是操纵光放大其频率通过一个独特的光致发光过程称为上转换（UC）的基础上的三重态-三重态湮灭（TTA）机制。通过TTA-UC过程，两个波长较高的光子（否则会被浪费）被组合并转换为波长较低的单个光子;这些上转换的光子随后用于敏化光催化剂并产生活性氧（ROS），从而有效地降解水中的污染物和微生物。研究人员将使用一对有机敏化剂和受体，使高效的可见光到可见光或蓝色到UVA的上转换成为可能。研究人员将选择各种发色团对，将它们封装到微胶囊中，并将它们与选定的半导体光催化剂偶联。将进行各种光致发光和光催化实验和仪器分析，以定量评估这个新系统的性能，包括量子产率，激发和发射光谱，能量转移过程的动力学（时间分辨光谱），和ROS的生产。材料合成和系统开发将专门针对水中污染物降解和微生物灭活以及使用后的分离和回收进行测试。确保获得廉价和清洁的水源是本世纪最大的全球挑战之一。先进的材料技术，如本项目开发的技术，提供了超越传统的基础设施密集型技术的机会，以便在工业化国家和发展中国家开发更可持续的方法，只要确保成本效益并避免不必要的附带影响。该项目具有开发太阳能技术的巨大潜力，该技术可以有效地收集太阳光谱中的低能量部分，否则这些部分将在任何现有的基于光催化剂的过程中被浪费。研究人员预计，具有提高的太阳能利用效率和易于分离的能力的UC/光催化剂可以容易地在各种环境工程实践中实施，包括太阳能光催化消毒（例如，使用太阳能集中器实现）、高级氧化和氧化还原。该项目旨在通过有效整合上转换，材料合成，半导体光刻，环境微污染物控制和消毒的生物物理学来实现这一目标。