Hybrid Halide Perovskite Materials for Photocatalytic Carbon-Carbon Bond Formation

植物的自然光合作用将阳光的能量储存在二氧化碳形成的新的碳-碳键中。21世纪的重大挑战之一是找出如何用被称为光催化剂的人造材料完成类似的化学反应。高效的光催化剂使用低成本和丰富的分子，如二氧化碳和甲烷，用于光驱生产有价值的有机化学品。科学家们一直在努力开发使用Ir或Ru等金属的光催化剂。然而，这些材料和目前正在研究的许多其他材料作为光催化剂表现不佳，价格昂贵，在地球上并不丰富，和/或难以回收利用。新泽西理工学院的严勇博士正在从完全由低成本和丰富元素组成的卤化铅钙钛矿开发出易于加工的光催化剂。这个项目的重点是证明小颗粒的钙钛矿型光催化剂可以帮助有效地形成新的碳-碳键。严教授致力于接触来自经济困难地区的学生、代表不足的少数民族和妇女。高中生实习生合成了一些用于该项目的钙钛矿纳米颗粒。在化学系化学催化计划的资助下，新泽西理工学院的严勇博士正在开发一种使用廉价的卤化铅钙钛矿纳米颗粒进行碳-碳键形成反应的新型光催化方法。APbX3钙钛矿，其中A是甲基铵或铯，X是卤化物，已经显示出成为一种高效和经济的光伏材料的潜力。这些钙钛矿由于其合成简单、反应后可加工性、由富含地球的元素组成、优异的光物理性质、易于调节的导电带和价带以及高催化周转数而在光催化有机合成中显示出良好的前景。虽然这些钙钛矿对水分的不稳定性阻碍了它们在光伏领域的应用，但水分敏感性对合适的有机溶剂的化学催化作用的阻碍较小。本项目考察了钙钛矿纳米颗粒在各种有机溶剂中的稳定性，以及它们在几种碳-碳键形成反应中的适用性。利用钙钛矿的带边调谐来调节其激发态氧化还原电势，以优化光催化有机合成。高中生实习生合成了一些用于该项目的钙钛矿纳米颗粒。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Natural photosynthesis in plants stores the energy of sunlight in new carbon-carbon bonds formed from carbon dioxide. One of the grand challenges of the 21st century is to figure out how to accomplish similar chemical reactions with man-made materials known as photocatalysts. Efficient photocatalysts use low cost and abundant molecules like carbon dioxide and methane for the light-driven production of valuable organic chemicals. Scientists have been trying to develop photocatalysts using metals such as iridium or ruthenium. However, these and many of the other materials currently under examination perform poorly as photocatalysts, are expensive, are not abundant on Earth, and/or are difficult to recycle. Dr. Yong Yan of the New Jersey Institute of Technology is developing easy-to-process photocatalysts from the lead halide perovskites that are composed entirely of low cost and abundant elements. This project focuses on demonstrating that small particles of perovskite photocatalysts can help to efficiently form new carbon-carbon bonds. Professor Yan engages in outreach to students from economically disadvantaged areas, to under-represented minorities, and women. High school student interns synthesize some of the perovskite nanoparticles used for this project.With funding support from the Chemical Catalysis Program of the Chemistry Division, Dr. Yong Yan of the New Jersey Institute of Technology is developing a novel photocatalytic approach for carbon-carbon bond formation reactions using inexpensive lead halide perovskite nanoparticles. APbX3 perovskite, where A is either methylammonium or cesium and X is a halide, has displayed the potential to be an efficient and cost-effective photovoltaic material. These perovskites also show promise for photocatalytic organic synthesis due to their simple synthesis, post-reaction processability, composition from earth-abundant elements, exceptional photophysical properties, readily tunable conduction and valence bands, and high catalytic turnover numbers. Although the instability of these perovskites towards moisture hinders their application as photovoltaics, moisture sensitivity is less of a hindrance for chemical catalysis with suitable organic solvents. This project examines the stability of perovskite nanoparticles in various organic solvents and their suitability for several carbon-carbon bond formation reactions. Band edge-tuning of perovskites is used to adjust their excited-state redox potential to optimize photocatalytic organic synthesis. High school student interns synthesize some of the perovskite nanoparticles used for this project.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.