Nanoclusters, nanoparticles, and surfaces: Bridging the gap between homogeneous and heterogeneous catalysis.

纳米团簇、纳米颗粒和表面：弥合均相催化和非均相催化之间的差距。

• 批准号: RGPIN-2021-03144
• 负责人: Crudden, Cathleen
• 金额: $ 8.81万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=747837
• 关键词: Nanoclusters; nanoparticles; surfaces; Bridging; gap

Gold nanoparticles date from Roman times, when mixing gold salts and molten glass gave bright red glasses by the unintentional formation of nanoparticles. These procedures were used for centuries, such that all stained-glass windows contain metallic nanoparticles. Despite the high level of sophistication in modern nanomaterials synthesis, these materials are still mixtures, with structures characterized by size distributions not precise chemical formulae. Since the properties of nanomaterials are fundamentally related to size, controlling and predicting these properties will always be guess work until precision synthesis methods are developed. Metal nanoclusters are an important advance towards the goal of precision synthesis, but they are still prepared using a black box approach that makes control and prediction of structure problematic. The ubiquity of size-focusing processes that etch cluster mixtures to enable the isolation of one product illustrates a lack of control of synthetic parameters. We will approach this challenging problem through the use of well-defined metal precursors with robust, easily tunable ligands. These ligands, (N-heterocyclic carbenes: NHCs), form exceptionally strong bonds to transition elements, and, in the last 6 yrs, we have shown that they also form highly robust monolayers on planar gold surfaces. Here we explore their applicability on nanoparticles and clusters. Our goal is to design novel, logical routes to nanomaterials through the use of stable, well-defined organometallic precursors, and stoichiometric reducing agents. We will use the NHC to tune the redox potential of the starting material, and to affect the electronics of the resulting cluster. We will move away from gold, developing routes to nanoclusters and nanoparticles from non-noble metals (Cu, Pd, Ru, Fe) addressing reactions of significant importance such as CH activation, CO2 reduction and alkane metathesis. The impact will be significant since nanomaterials provide an important bridge between well understood molecular catalysts and less understood but industrially relevant heterogeneous catalysts. Structure/activity relationships obtained from nanomaterial catalysis will enable improvements in existing processes and the development of new ones such as alkane metathesis, which can convert plastic waste into valuable chemicals. This work is highly collaborative, providing exceptional learning opportunities for  graduate students and PDFs. We strive to understand the techniques employed by collaborators, which translates to students learning materials characterization techniques along with materials/organometallic synthesis. We currently have internal experts in X-ray photoelectron spectroscopy, electrochemistry, synthesis and nanocluster purification/crystallization. I strongly believe in research exchanges for PhD students, which may revolve around learning new techniques, and will provide these opportunities for my students.

金纳米颗粒的历史可追溯至罗马时代，当混合金盐和熔融玻璃时，纳米颗粒的无意形成给出了鲜红色的眼镜。这些程序使用了几个世纪，以使所有彩色玻璃窗都包含金属纳米颗粒。尽管现代纳米材料的合成中具有高水平的复杂水平，但这些材料仍然是混合的，其结构由大小分布而不是精确的化学配方。由于纳米材料的性质基本上与大小有关，因此控制和预测这些特性将始终是猜测工作，直到开发精确合成方法。金属纳米簇是朝着精确合成目标的重要进步，但是它们仍在使用黑匣子方法来制备，从而使结构的控制和预测有问题。蚀刻群集混合以使一种产品的分离的尺寸关注过程的无处不在，这说明了对合成参数的缺乏控制。我们将通过使用定义良好的金属前体和可调，易于调谐的配体来解决这个挑战问题。这些配体（N-杂环碳纤维：NHC）与过渡元件形成了异常牢固的键，并且在最后6年中，我们表明它们还在平面金表面上形成了非常强大的单层。在这里，我们探索它们在纳米颗粒和簇上的适用性。我们的目标是通过使用稳定，定义明确的有机前体和化学计量的还原剂来设计新颖的逻辑路线，以纳米材料为纳米材料。我们将使用NHC调整起始材料的氧化还原电位，并影响所得群集的电子。我们将从非缺失金属（Cu，Pd，Ru，Fe）的纳米簇和纳米颗粒中转移到黄金，开发到纳米群体和纳米颗粒，以解决重要性的反应，例如CH激活，CO2还原和烷烃分解。由于纳米材料提供了知识良好的分子催化剂和知识较少，但与工业相关的异质催化剂之间的重要桥梁，因此影响很大。从纳米材料催化获得的结构/活动关系将使现有过程和新过程的发展（例如烷烃元理）的发展，这些过程可以将塑料废物转化为有价值的化学物质。这项工作是高度协作的，为研究生和PDF提供了出色的学习机会。我们努力理解合作者使用的技术，这些技术转化为学生学习材料表征技术以及材料/有机金属合成的技术。我们目前拥有X射线光电子光谱，电化学，合成和纳米簇纯化/结晶方面的内部专家。我坚信博士生的研究交流可能围绕学习新技术，并将为我的学生提供这些机会。