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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742400
• 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.

金纳米粒子的历史可以追溯到罗马时代，当时将金盐和熔融玻璃混合，通过无意中形成的纳米粒子产生了明亮的红色玻璃。这些程序已经使用了几个世纪，以至于所有的彩色玻璃窗都含有金属纳米颗粒。尽管现代纳米材料合成的复杂程度很高，但这些材料仍然是混合物，其结构特征是尺寸分布而不是精确的化学式。由于纳米材料的性质从根本上与尺寸有关，因此在开发出精确的合成方法之前，控制和预测这些性质将始终是猜测工作。金属纳米团簇是实现精确合成目标的一个重要进展，但它们仍然是使用黑箱方法制备的，这使得结构的控制和预测成为问题。普遍存在的尺寸聚焦过程，蚀刻集群混合物，使一个产品的隔离说明了缺乏控制的合成参数。 我们将通过使用定义明确的金属前体与强大的，易于调谐的配体来解决这个具有挑战性的问题。这些配体（N-杂环卡宾：NHC）与过渡元素形成非常强的键，并且在过去的6年中，我们已经证明它们也在平面金表面上形成高度稳健的单层。在这里，我们探讨其适用性的纳米粒子和集群。 我们的目标是通过使用稳定的、定义明确的有机金属前体和化学计量的还原剂来设计新颖的、合乎逻辑的纳米材料路线。我们将使用NHC来调整起始材料的氧化还原电位，并影响所得簇的电子学。我们将远离黄金，开发从非贵金属（Cu，Pd，Ru，Fe）到纳米团簇和纳米颗粒的路线，解决重要的反应，如CH活化，CO2还原和烷烃复分解。 影响将是显著的，因为纳米材料提供了一个重要的桥梁之间的分子催化剂和不太了解，但工业相关的非均相催化剂。从纳米材料催化中获得的结构/活性关系将有助于改进现有工艺和开发新工艺，如烷烃复分解，可以将塑料废物转化为有价值的化学品。这项工作是高度协作的，为研究生和PDF提供了特殊的学习机会。我们努力理解合作者所采用的技术，这转化为学生学习材料表征技术沿着材料/有机金属合成。我们目前拥有X射线光电子能谱、电化学、合成和纳米团簇纯化/结晶方面的内部专家。我坚信博士生的研究交流，这可能围绕着学习新技术，并将为我的学生提供这些机会。