Rational design of photocatalysts

光催化剂的合理设计

• 批准号: 2606057
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2606057
• 关键词: Rational; design; photocatalysts

Photo-redox catalysis has gained a lot of interest due to its potential of performing otherwise difficult chemical conversions and its ability to use visible or near UV light, that can be efficiently generated with LEDs. While it has been demonstrated in a range of applications, there is no clear concept for photocatalyst design and the exact catalyst used in an application appears to be by trial and error rather than guided by understanding and rational design criteria. This project aims at combining modelling and experimental work to design and optimize photocatalyst performance based on the following criteria (among others): - Light absorption: the energy available for lifting electrons of a substrate into an excited orbital will depend on the energy transferred from the photocatalyst to the substrate and therefore ultimately on the energy absorbed by the photocatalyst. - Sorption properties (heterogeneous catalysts): The adsorption of a substrate to a heterogeneous photocatalyst is a prerequisite to the energy transfer from the catalyst to the substrate. Assuming that the substrate is then ready to perform the reaction with a second reagent, the sorption properties of the latter to the catalyst surface will affect the reaction pathway and the required catalyst surface. And finally the desorption of the product (or the reagents) from the surface will affect the performance of the catalytic system, as it will free up the surface for the next set of reagent molecules to be converted into product- Coordination properties (heterogeneous catalysts): The coordination of substrates to photocatalytically active coordination metals will determine, whether a reaction is catalyzed and how the catalytic cycle looks like. - Electronic properties of the catalytic system: a typical redox photocatalytic system includes one catalyst for the reduction and another one for the oxidation reaction. This entails that electrons can move from the oxidizing catalyst to the site, where the corresponding reduction is to be performed (and to avoid electron-hole recombination). Identifying an appropriate pair of catalysts and combining them in an appropriate way, so the electrons can move as required will be crucial for the performance of the photo-redox-catalytic system. (Note that also mass transport of molecules/ions/moieties will be required to close the catalytic cycle.) This Ph.D. programme will be looking at the critical aspects of one to three exemplars for redox-photocatalytic systems - By modelling the above (and significant other) parameters - By experimentally testing, verifying, refining the models. This will include analyzing the product stream with respect to products and side products and develop concepts for the underlying reaction network.One goal will include the identification of the rate-/performance-limiting steps or features in a photocatalytic system and suggest measures to improve the effectiveness and efficiency (yield and selectivity, turn-over number, etc.) of the system and suggest appropriate catalyst combinations and formulations,The programme will aim at leveraging synergies with two other students within React by focusing on one photocatalytic system. One of the students is working on the synthesis and analysis of an oxidizing photocatalyst (Melanie Nutter), the other one (Janusz Siwek) on reactor design and scale up.

光氧化还原催化由于其执行其他困难的化学转化的潜力以及其使用可见光或近紫外光的能力而获得了很多兴趣，这可以通过LED有效地产生。虽然它已在一系列应用中得到证明，但光催化剂设计没有明确的概念，并且应用中使用的确切催化剂似乎是通过反复试验，而不是通过理解和合理的设计标准来指导。该项目旨在结合建模和实验工作，根据以下标准（其中包括）设计和优化光催化剂性能：-光吸收：可用于将衬底的电子提升到激发轨道的能量将取决于从光催化剂转移到衬底的能量，因此最终取决于光催化剂吸收的能量。- 吸附性能（多相催化剂）：基质对多相光催化剂的吸附是能量从催化剂转移到基质的先决条件。假设基材然后准备好与第二试剂进行反应，后者对催化剂表面的吸附性质将影响反应途径和所需的催化剂表面。最后，产物（或试剂）从表面的解吸将影响催化系统的性能，因为它将释放表面以用于下一组试剂分子转化为产物-配位性质（多相催化剂）：底物与光催化活性配位金属的配位将决定反应是否被催化以及催化循环的样子。- 催化体系的电子性质：典型的氧化还原光催化体系包括一种用于还原的催化剂和另一种用于氧化反应的催化剂。这使得电子可以从氧化催化剂移动到要进行相应还原的位置（并避免电子-空穴复合）。确定一对合适的催化剂并以适当的方式将它们组合在一起，使电子可以根据需要移动，这对于光氧化还原催化系统的性能至关重要。(Note也需要分子/离子/部分的质量传递来关闭催化循环）。这个博士该计划将着眼于氧化还原-光催化系统的一到三个范例的关键方面-通过模拟上述（和其他重要）参数-通过实验测试，验证，改进模型。这将包括分析产品流中的产物和副产物，并为潜在的反应网络开发概念。其中一个目标将包括识别光催化系统中的速率/性能限制步骤或特征，并提出提高有效性和效率的措施（产率和选择性，周转数等）。该计划旨在通过专注于一个光催化系统，利用与React内其他两名学生的协同效应。其中一名学生从事氧化光催化剂的合成和分析（Melanie Nutter），另一名学生（Janusz Siwek）从事反应器设计和放大。