CAREER: CAS: Combining Main Group and Transition Metals to Tune the Electronic Structure, Photophysics, and Photocatalytic Activity of Spinel Oxide Nanocrystals

职业：CAS：结合主族和过渡金属来调节尖晶石氧化物纳米晶体的电子结构、光物理和光催化活性

• 批准号: 2044462
• 负责人: Kathryn Knowles
• 金额: $ 69.86万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2044462&HistoricalAwards=false
• 关键词: CAREER; CAS; Combining; Main; Group

With the support of the Macromolecular, Supramolecular and Nanochemistry (MSN) Program in the Division of Chemistry, Dr. Kathryn Knowles of the University of Rochester will develop novel synthetic approaches to mixed-metal oxide nanocrystals and investigate their properties. This research aims to generate a comprehensive fundamental understanding of the structure-property relationship in this class of nanocrystals that has the potential to facilitate rapid degradation, using sunlight, of persistent organic pollutants in water sources. These pollutants, such as dyes, pesticides, herbicides, and "forever chemicals" (per- and polyfluoroalkyl compounds), in the environment can have negative impacts on human health. The magnetic properties of the nanocrystals will allow their easy recovery from solution after use. Dr. Knowles and her team also seek to cultivate positive attitudes about scientific research in undergraduate and elementary school students by engaging them in activities that capture the creative and collaborative aspects of scientific research. These activities include an open-ended, inquiry-based capstone project to be incorporated into an upper-level undergraduate physical chemistry course and scientific activities that will be disseminated to a large, diverse cohort of elementary school students in a virtual format during National Chemistry Week.The long-term goal of this research is to enable the rational design of visible light-absorbing semiconductors with efficient separation of photogenerated charges and slow carrier recombination kinetics for used as photoactive components of light-harvesting technology. This research will integrate nanocrystal synthesis, electronic structure calculations, and spectroscopic measurements to generate a comprehensive fundamental understanding of the relationships between composition, electronic structure, photophysical properties, and excited state dynamics of colloidal spinel oxide nanocrystals of general formula AB2O4. The Knowles group will establish a library of heterobimetallic molecular cluster precursors that will provide access to a broad range of spinel oxide compositions. Incorporating main group and transition metal cations into the same metal oxide nanocrystals will enable systematic examination of the synergistic effects of combining metal cations containing empty s-orbitals and partially filled 3d orbitals on the optical, electronic, and excited state properties of metal oxide nanocrystals. Density functional theory calculations, transient absorption and electrochemical impedance spectroscopies, and photocatalysis experiments will (i) predict and confirm the dependence of electronic and photophysical properties of spinel oxide nanocrystals on their composition and (ii) correlate the band-edge redox potentials and excited-state dynamics of these nanocrystals with their ability to photocatalyze the oxidative degradation of a broad range of organic pollutants.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.

在化学系高分子、超分子和纳米化学 (MSN) 项目的支持下，罗切斯特大学的 Kathryn Knowles 博士将开发混合金属氧化物纳米晶体的新型合成方法并研究其特性。这项研究旨在对这类纳米晶体的结构-性能关系产生全面的基本了解，这种纳米晶体有可能利用阳光促进水源中持久性有机污染物的快速降解。环境中的这些污染物，例如染料、杀虫剂、除草剂和“永久化学品”（全氟烷基化合物和多氟烷基化合物），可能对人类健康产生负面影响。纳米晶体的磁性使它们在使用后很容易从溶液中回收。 诺尔斯博士和她的团队还致力于通过让本科生和小学生参与体现科学研究的创造性和协作性的活动来培养他们对科学研究的积极态度。这些活动包括一个开放式、基于探究的顶点项目，该项目将被纳入高年级本科物理化学课程，以及科学活动，这些活动将在国家化学周期间以虚拟形式向大量不同的小学生传播这项研究的长期目标是合理设计可见光吸收半导体，具有光生电荷的有效分离和慢载流子复合动力学，用作光捕获技术的光活性组件。这项研究将整合纳米晶体合成、电子结构计算和光谱测量，以全面了解通式AB2O4的胶体尖晶石氧化物纳米晶体的组成、电子结构、光物理性质和激发态动力学之间的关系。诺尔斯集团将建立一个异质双金属分子簇前体库，该库将提供广泛的尖晶石氧化物组合物。将主族和过渡金属阳离子纳入相同的金属氧化物纳米晶体中，将能够系统地研究包含空 s 轨道和部分填充的 3d 轨道的金属阳离子组合对金属氧化物纳米晶体的光学、电子和激发态性质的协同效应。 密度泛函理论计算、瞬态吸收和电化学阻抗谱以及光催化实验将（i）预测并确认尖晶石氧化物纳米晶体的电子和光物理性质对其组成的依赖性，以及（ii）将带边氧化还原电位与激发态相关联。这些纳米晶体的状态动力学及其光催化氧化降解多种有机污染物的能力。该奖项反映了 NSF 的法定使命，并被认为值得通过以下方式获得支持使用基金会的智力价值和更广泛的影响审查标准进行评估。

项目成果

Modelling local structural and electronic consequences of proton and hydrogen-atom uptake in VO 2 with polyoxovanadate clusters

用多钒酸盐簇模拟 VO 2 中质子和氢原子吸收的局部结构和电子后果

• DOI: 10.1039/d1sc02809j
• 发表时间: 2021-10
• 期刊: Chemical Science
• 影响因子: 8.4
• 作者: Chakraborty, Sourav;Schreiber, Eric;Sanchez;Tariq, Mehrin;Brennessel, William W.;Knowles, Kathryn E.;Matson, Ellen M.
• 通讯作者: Matson, Ellen M.

Cation Distribution in Spinel Ferrite Nanocrystals: Characterization, Impact on their Physical Properties, and Opportunities for Synthetic Control

尖晶石铁氧体纳米晶体中的阳离子分布：表征、对其物理性能的影响以及合成控制的机会

• DOI: 10.1021/acs.inorgchem.1c00040
• 发表时间: 2021-04
• 期刊: Inorganic Chemistry
• 影响因子: 4.6
• 作者: Sanchez;Stair, James L.;Knowles, Kathryn E.
• 通讯作者: Knowles, Kathryn E.

Polaronic optical transitions in hematite (α-Fe 2 O 3 ) revealed by first-principles electron–phonon coupling

第一原理电子声子耦合揭示赤铁矿 (α-Fe 2 O 3 ) 中的极化光学跃迁

• DOI: 10.1063/5.0116233
• 发表时间: 2022-11
• 期刊: The Journal of Chemical Physics
• 作者: Shelton, Jacob L.;Knowles, Kathryn E.
• 通讯作者: Knowles, Kathryn E.

Thermally Activated Optical Absorption into Polaronic States in Hematite

赤铁矿中极化状态的热激活光学吸收

• DOI: 10.1021/acs.jpclett.0c03751
• 发表时间: 2021-04
• 期刊: The Journal of Physical Chemistry Letters
• 作者: Shelton, Jacob L.;Knowles, Kathryn E.
• 通讯作者: Knowles, Kathryn E.

Controlling Cation Distribution and Morphology in Colloidal Zinc Ferrite Nanocrystals

• DOI: 10.1021/acs.chemmater.2c01568
• 发表时间: 2022-08-23
• 期刊: Chemistry of Materials
• 影响因子: 8.6
• 作者: Sanchez-Lievanos, Karla R.;Knowles, Kathryn E.
• 通讯作者: Knowles, Kathryn E.