CAREER: Elucidation of the mechanistic origins of plasmon-induced chemical reactions

有了这个职业奖，化学系的大分子、超分子和纳米化学项目支持伊利诺伊大学的Prashant Jain教授研究光能在金属材料中转化为化学能的详细方式。这一过程，如果得到适当的理解和控制，可能成为捕获太阳能和用光驱动化学工业中能源密集型过程的候选技术。Jain教授的目标是制备强吸光材料，这种材料可以有效地将太阳光转化为燃料中的化学能。另一项努力涉及使用更便宜、更丰富的材料实现光能到化学能的转换。除了实验室的努力外，一个交互式软件工具正在开发中，并用于光与物质相互作用的教育。该教育计划旨在通过生动的、动手操作的光学例子，在课堂上培养早期的科学兴趣，为高中、本科生和研究生未来的科学和技术职业做好准备。外展活动旨在促进社区认识到太阳能是一种清洁、可再生的矿物燃料替代品。Jain教授研究了含贵金属异质结构的等离子体激发在纳米结构表面诱导或催化化学反应的物理化学机制。在这个项目中，研究了由金纳米粒子与半导体氧化物（二氧化钛和氧化锌）接触组成的等离子体异质结构，以确定等离子体近场增强、热电子转移和光热加热在光催化反应中的相对贡献。本研究旨在阐明氧化物的机制作用，并评估氧化物中载流子的近场辅助带隙或亚带隙光激发是观察到的光活性的原因，还是金属/氧化物之间的电荷分离是一个更重要的因素。Jain教授使用单分子荧光来确定光反应是发生在金属上、半导体氧化物上，还是发生在金属/氧化物界面上。最后，他探索了在无贵金属的等离子体氧化物中等离子体激发诱导的光催化，这代表了一个无界面的系统，其中等离子体激发和半导体电子跃迁都定位在同一晶体内。

With this CAREER Award, the Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry is supporting Professor Prashant Jain of the University of Illinois to study the detailed manner in which light energy is converted into chemical energy within metallic materials. This process, if properly understood and controlled, may become a candidate technology for capturing solar energy and for driving energy-intensive processes in the chemical industry with light. Professor Jain aims at preparing strongly light-absorbing materials that can efficiently convert sunlight into chemical energy in fuels. Another effort involves the achievement of light-to-chemical energy conversion using cheaper, more abundant materials. Alongside the laboratory efforts, an interactive software tool is being developed and employed for the purpose of education on the interaction of light with matter. The educational program is aimed at generating early scientific interest in the classroom by means of vivid, hands-on examples from optics, preparing high school, undergraduate, and graduate students for future science and technology careers. Outreach activities seek to foster community awareness of solar energy as a clean, renewable alternative to energy from fossil fuels. Professor Jain investigates the physicochemical mechanism(s) by which the plasmonic excitation of a noble metal-containing heterostructure induces or catalyzes chemical reactions on the surface of the nanostructure. In this project, a plasmonic heterostructure consisting of Au nanoparticles in contact with a semiconducting oxide (titanium dioxide and zinc oxide) is studied for determining the relative contributions of plasmonic near-field enhancement, hot electron transfer, and photothermal heating in photocatalytic reactions. This research aims to elucidate the mechanistic role of the oxide and assess whether near-field-assisted bandgap or sub-bandgap photoexcitation of carriers in the oxide is responsible for the observed photoactivity, or, whether charge separation across the metal/oxide is a more important contributor. Professor Jain uses single-molecule fluoresence to identify whether the photoreaction takes place on the metal, on the semiconducting oxide, or at the metal/oxide interface. Finally, he explores plasmon excitation-induced photocatalysis in a noble metal-free plasmonic oxide, which represents an interface-free system where plasmonic excitation and semiconductor electronic transitions are localized within the same crystallite.