Energy funneling in plasmonic nanocrystal composites for photocatalytic production of solar fuels

用于光催化生产太阳能燃料的等离子体纳米晶体复合材料中的能量漏斗。鲍灵格林州立大学的米哈伊尔·扎姆科夫正在开发一种新的模型系统，用于在胶体纳米结构中进行太阳能转换，旨在提高其光催化活性。所提出的纳米材料结构被设计成通过内置天线将太阳光线射入复合纳米颗粒的中心。然后，吸收的辐射被引导到纳米颗粒的外部，以驱动其表面的催化反应。为了实现高效的催化循环，在天线和催化剂之间采用了一种新型的能量传递机制。提出的创新利用了复合纳米物体无机域之间精心设计的界面，以确保太阳能在光催化系统中的无缝转移。催化纳米结构是可溶的，这使得表面均相反应的优点（出色的活性和选择性）与非均相系统回收催化剂的便利相结合。这些材料特别适合驱动水相反应，包括氢气生产和环境净化，在太阳通量下具有增强的反应性。这个拟议中的项目有助于研究者每年夏天继续从代表性不足的群体中招募几名学生到实验室进行全职研究实习。研究者还与几个工业合作伙伴进行交互，为本科生研究人员提供工业实验室经验。在这个由化学催化项目资助的项目中，鲍灵格林州立大学的Mikhail Zamkov博士专注于新型合成策略和超快光谱技术的协同作用，以探索利用复合胶体纳米结构的新型光催化材料。所提出的纳米材料将多个无机结构域结合在一个纳米反应器中，旨在有效地将太阳辐射转化为催化活性状态。纳米材料结构的关键创新在于等离子体辅助光捕获方案，该方案利用金属纳米颗粒中存在的强电磁场来促进周围半导体外壳中激子的产生。然后将壳的激发能传递给表面上合适的氧化/还原催化剂。为了确保复合纳米对象的不同成分无缝工作，使用分子外延生长域间界面。这样的化学计量键，无论是共价键还是离子键，都降低了缺陷态的密度，从而使吸收的辐射具有高通量，从而耗散激发能。研究人员利用水介质中常见的氧化还原反应测试了胶体纳米结构的催化性能，同时利用超快光谱技术研究了能量传递过程。作为“建设俄亥俄可持续能源未来”和“俄亥俄科学、工程和技术门户”项目的积极成员，Zamkov教授在这个研究项目中让本科生组成小团队，向他们介绍超快光谱、材料科学和化学合成的一般概念。为让少数民族学生和代表性不足群体的学生参与其中作出了特别努力。Zamkov教授还与几个工业合作伙伴合作，为本科生研究人员提供工业实验室经验。

Energy funneling in plasmonic nanocrystal composites for photocatalytic production of solar fuels.Dr. Mikhail Zamkov of Bowling Green State University is developing a novel model system for solar energy conversion in colloidal nanostructures aimed toward improving their photocatalytic activity. The proposed nanomaterial architecture is designed to funnel the solar light into the center of a composite nanoparticle via a built-in antenna. The absorbed radiation is then routed toward the exterior of the nanoparticle to drive catalytic reactions on its surface. To enable an efficient catalytic cycle, a novel type of energy transfer mechanism between the antenna and the catalyst is employed. The proposed innovation makes use of judiciously engineered interfaces between inorganic domains of the composite nano-object to ensure a seamless transfer of the solar energy across the photocatalytic system. The catalytic nanostructures are rendered soluble, which allows combing the benefits of homogenous reactions on the surface (excellent activity and selectivity) with the facility of the heterogeneous systems to recycle the catalyst. These materials are particularly suited to drive aqueous phase reactions, including hydrogen production and environmental clean-up, with enhanced reactivity under the solar flux. The proposed project helps the investigator in his effort to continue to bring in several students from underrepresented groups each summer for a full-time research internship in the lab. The investigator also interfaces with several industrial partners to provide the undergraduate researchers with industrial laboratory experience.In this project, funded by the Chemical Catalysis Program, Dr. Mikhail Zamkov of Bowling Green State University focuses on the synergy of novel synthetic strategies and ultrafast spectroscopy techniques to explore a new class of photocatalytic materials utilizing composite colloidal nanostructures. The proposed nanomaterials combine several inorganic domains in a single nano-reactor designed to efficiently convert the solar radiation into a catalytically active state. The key innovation of the nanomaterial architecture lies in the plasmon-assisted light-harvesting scheme, which takes advantage of the strong electro-magnetic field that exists in metal nanoparticles to boost the production of excitons in the surrounding semiconductor shell. The excitation energy of the shell is then relayed to suitable oxidation/reduction catalysts on the surface. To ensure that different constituents of the composite nano-object work seamlessly, inter-domain interfaces are grown using molecular epitaxy. Such stoichiometric bonds, either covalent or ionic, reduce the density of defect states that dissipate the excitation energy enabling a high throughput of the absorbed radiation. The catalytic performance of the investigator's colloidal nanostructures are tested using common redox reactions in aqueous media, while the energy transfer processes are investigated using ultrafast spectroscopy techniques. As an active member of Building Ohio's Sustainable Energy Future and Science, Engineering & Technology Gateway Ohio programs, Professor Zamkov involves small teams of undergraduate students in this research project, introducing them to general concepts in ultrafast spectroscopy, material science, and chemical synthesis. Special efforts are made to involve minority students and students from underrepresented groups. Professor Zamkov also interfaces with several industrial partners to provide the undergraduate researchers with industrial laboratory experience.