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

金纳米粒子可以追溯到罗马时代，当时金盐和熔融的玻璃混合在一起，无意中形成了明亮的红色玻璃。这些程序被使用了几个世纪，因此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性很高，但这些材料仍然是混合物，其结构的特征是粒度分布，而不是精确的化学式。由于纳米材料的性能从根本上与尺寸有关，因此在开发出精确的合成方法之前，控制和预测这些性能一直是一项猜测工作。金属纳米团簇是迈向精确合成目标的重要进展，但它们的制备仍然使用黑盒方法，这使得结构的控制和预测成为问题。刻蚀簇混合物以分离一种产品的尺寸聚焦工艺无处不在，这表明缺乏对合成参数的控制。我们将通过使用定义明确的金属前驱体和坚固的、易于调节的配体来解决这一具有挑战性的问题。这些配体(N-杂环卡宾：NHC)与过渡元素形成了非常强的键，在过去的6年里，我们已经证明它们也在平面金表面形成了非常坚固的单分子膜。在这里，我们探索它们在纳米颗粒和团簇上的适用性。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比的还原剂来设计新的、合理的纳米材料路线。我们将使用NHC来调整起始材料的氧化还原电势，并影响所产生的团簇的电子学。我们将从黄金转向纳米团簇和非贵金属(铜、钯、Ru、铁)纳米颗粒，解决CH活化、二氧化碳还原和烷烃歧化等重要反应。这一影响将是巨大的，因为纳米材料在人们熟知的分子催化剂和不太了解但具有工业相关性的多相催化剂之间架起了一座重要的桥梁。通过纳米材料催化获得的结构/活性关系将使现有工艺的改进和新工艺的开发成为可能，例如烷烃化合作用，它可以将塑料废物转化为有价值的化学品。这项工作具有高度的协作性，为研究生和PDF提供了非凡的学习机会。我们努力了解合作者使用的技术，这意味着学生学习材料表征技术以及材料/有机金属合成。我们目前在X射线光电子能谱、电化学、合成和纳米团簇提纯/结晶方面拥有国内专家。我非常相信博士生的研究交流，这可能围绕学习新技术展开，并将为我的学生提供这些机会。

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.