Size dependent electronic, structural and catalytic properties of nanostructured supported metal oxide clusters

纳米粒子/团簇的最重要的应用之一是多相催化，其中可以利用大的表面积与体积比。大多数情况下，然后将簇沉积在一些基底上，这使得对催化反应的细节进行详细的理论和/或实验研究非常困难。催化反应中最重要的一类是某些体系的氧化反应。对于这些反应，使用金属氧化物作为催化剂是有优势的。本项目的目标是对一个简单的模型反应--CO的氧化反应进行原子理解。作为催化剂，将研究钛和钒氧化物簇，它们依次沉积在石墨烯或二氧化硅上。应研究不同的M（x）O（y）团簇，其中N = x+y高达约50。应研究化学计量团簇（M = Ti时y/x = 2，M = V时y/x = 2.5）以及富氧或贫氧的近化学计量团簇。第一个挑战将是确定集群的结构。为此，我们将应用无偏的方法，我们已经用于孤立的纳米粒子在气相中，因为几年。作为一种方法，我们将对随后将沉积在衬底上的气相中的颗粒使用这些方法。作为替代方案，我们将确定直接在基底上形成的这种团簇的最佳结构。随后，我们将研究CO的氧化。这一部分将与印度同事Neetu Goel博士密切合作完成，他的经验将对该项目大有裨益。几年来，她一直致力于催化的理论研究，这一经验以极好的方式补充了我们的经验。应研究不同类型催化剂的催化反应：气相中的孤立簇、沉积在基片上的簇和直接生长在基片上的簇。金属氧化物团簇中的氧在催化反应中起积极作用，是化学计量的还是接近化学计量的（贫氧或富氧）簇是更好的催化剂，底物对于催化反应有多重要。

One of the most important applications of nanoparticles / clusters is that of heterogeneous catalysis, for which the large surface-to-volume ration can be exploited. Most often, the clusters are then deposited on some substrate, which makes detailed theoretical and/or experimental studies of the details of the catalytic reactions very difficult. One of the most important classes of catalytic reactions is the oxidation of some system. For those reactions, it can be of advantage to use metal oxides as catalysts.The goal of the proposed project is to develop an atomistic understanding of a simple model reaction, the oxidation of CO. As catalysts, titanium and vanadium oxide clusters will be studied that in turn are deposited on either graphene or silica. Different M(x)O(y) clusters with N = x+y up to around 50 shall be studied. Both stoichiometric clusters (y/x = 2 for M = Ti, y/x = 2.5 for M = V) as well as near-stoichiometric either O rich or O poor shall be studied. The first challenge will be to determine the structures of the clusters. To this end, we shall apply the unbiased methods that we have been used for isolated nanoparticles in the gas phase since several years. As one approach we shall use exactly those methods for the particles in the gas phase that subsequently shall be deposited on the substrate. As an alternative we shall determine the optimal structures for such clusters when created directly on the substrate.Subsequently, we shall study the oxidation of CO. This part shall be done in close collaboration with an Indian colleague, Dr. Neetu Goel, whose experience will be of great benefit to the project. Since several years she has been working on theoretical studies of the catalysis, an experience that in excellent way complements our own. The catalytic reaction shall be studied for different types of catalysts: isolated clusters in the gas phase, such clusters deposited on the substrate, and clusters grown directly on the substrate.The project is expected to address the following issues: does oxygen of the metal oxide clusters play an active role in the catalytic reaction, are stoichiometric or near-stoichiometric (oxygen-poor or -rich) clusters the better catalysts, how important are the substrates for the catalytic reaction.