High-Energy Hot Electrons from Ultraviolet-Plasmonic Rhodium Nanoparticles for Plasmon-enhanced Photocatalysis

考虑到化石燃料的有限供应和消费所造成的环境影响，利用充足的阳光来生产清洁能源燃料和所需的化学品具有巨大的社会效益。 最近，一种特殊的金属纳米颗粒家族被提出用作光催化剂，可以实现太阳能收集并帮助进行所需的化学反应。 这些纳米颗粒的特征在于由于小的纳米颗粒尺寸对金属的电子结构的影响（等离子体效应）而具有强的光吸收。 在这个项目中，Jie Liu博士正在探索等离子体激元的机理以及这些纳米催化剂的物理和化学性质对其催化活性和产物选择性的影响。该研究对设计高性能等离子体光催化剂具有更广泛的影响，这些等离子体光催化剂用于经济上重要的化学反应，如二氧化碳捕获。刘博士积极参与教育和外展活动。他通过杜克大学纳米科学和纳米技术网络（杜克N3）为研究生和本科生组织校园范围的社交和网络活动。他还通过NC SEED计划让高中生参与他的研究，该计划支持和鼓励有才华、处境不利的北卡罗来纳州高中生攻读化学和物理学研究生学位，在化学部化学催化计划的资助下，杜克大学的刘博士正在对紫外等离子体铑（Rh）本发明涉及纳米颗粒催化光催化转化以及等离子体金属纳米结构的性质如何决定它们的光催化活性和产物选择性。等离子体Rh纳米粒子和吸附在其表面上的分子之间的电荷转移过程，在光催化反应中活化反应物的关键步骤，通过光谱方法进行了研究。两个光催化反应，即乙烯环氧化和二氧化碳还原，作为模型反应进行了研究，以了解如何从等离子体激元光催化剂的热电子使动力学缓慢或pherically不利的反应。Rh纳米颗粒的化学和物理性质，包括尺寸，形状和共振能量对其催化活性和选择性的影响也在研究中。除了实验研究，密度泛函理论（DFT）的计算进行，以获得势能景观的基本步骤的反应和阐明的机制，热电子诱导的光催化转化。刘博士还积极参与教育和外展活动，对当地社区产生广泛影响。他组织了校园范围内的社交和网络活动，涉及研究生和本科生，在这些活动中有大量的女科学家。他还通过NC SEED项目让高中生参与研究，该项目支持处境不利的北卡罗来纳州高中生攻读化学和物理研究生学位。

Considering the limited supply and environmental impact caused by the consumption of fossil fuels, harnessing abundant sunlight to produce clean energy fuels and desirable chemicals is of great societal benefit. Recently, a special family of metal nanoparticles has been proposed for use as photocatalysts that can effect solar harvesting and help perform the desired chemical reactions. These nanoparticles are characterized by strong light absorption due to the effect of the small nanoparticle size on the metal's electronic structure (the plasmonic effect). In this project, Dr. Jie Liu is exploring the mechanism of plasmonic photocatalysis and the influence of the physical and chemical properties of these nanocatalysts on their catalytic activity and product selectivity. The research has broader impact for the design of high-performance plasmonic photocatalysts of economically important chemical reactions such as carbon dioxide capture. Dr. Liu is actively involved in education and outreach activities. He organizes campus-wide social and networking events for graduate and undergraduate students through Duke University Network in Nanoscience and Nanotechnology (Duke N3). He also involves high school students in his research through the NC SEED program, which supports and encourages talented, disadvantaged North Carolina high school students to pursue graduate degrees in chemistry and physics.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Liu of Duke University is developing a fundamental understanding of how ultraviolet-plasmonic rhodium (Rh) nanoparticles catalyze photocatalytic transformations and how the properties of the plasmonic metal nanostructures determine their photocatalytic activity and product selectivity. The charge-transfer process between the plasmonic Rh nanoparticles and adsorbed molecules on their surface, a critical step in activating reactants in photocatalytic reactions, is studied by spectroscopic methods. Two photocatalytic reactions, namely ethylene epoxidation and carbon dioxide reduction, are studied as model reactions to obtain understanding on how hot electrons from the plasmonic photocatalysts enable kinetically sluggish or thermodynamically unfavorable reactions. The effects of the chemical and physical properties of Rh nanoparticles, including size, shape and resonant energy, on their catalytic activity and selectivity is also under investigation. In addition to the experimental investigation, density functional theory (DFT) calculations are conducted to obtain the potential energy landscape in elementary steps of the reactions and elucidate the mechanism of the hot electron induced photocatalytic transformations. Dr. Liu is also actively involved in education and outreach activities with broad impact on his local community. He organizes campus-wide social and networking events involving graduate students and undergraduate students with strong presence of women scientists in these events. He also involves high school students in the research through the NC SEED program, which supports disadvantaged North Carolina high school students to pursue graduate degrees in chemistry and physics.