Computational Modelling of the Formation and Stability of Supported Particles of Catalytic Importance

由于现代社会要求在高效技术和清洁能源的基础上提高生活质量，当代科学家关注的是在环保条件下具有特定性能的新材料。尺寸小于100纳米的结构表现出与块状材料不同的性能。这种规模在一个不断发展的领域开辟了新的研究边界，具有广泛的影响。例如，当前工业在制造大量日常产品时使用纳米材料。在化学工业中，这些细小颗粒通常是分散在支撑材料上的金属，在产品制造过程中降低了成本和废物产量。然而，科学家们主要采用“混合和尝试”的方法来合成，因为形成过程的复杂性和纳米结构的稳定性受到多种参数的影响，如温度、压力和金属前驱体。颗粒的性能取决于它们的大小和形状。因此，我们的目标是通过计算确定影响特定表面上金属颗粒生长和稳定性的热力学和动力学描述符。这个项目将使我们能够解开支撑、金属和纳米颗粒尺寸的影响，同时考虑颗粒的形状和在表面上的扩散，这将有助于理解在工作条件下催化剂的烧结和失活等过程。特别是，我们建议将一些晚期过渡金属与表征良好的表面结合起来，因为它们在工业催化中的重要性和广泛的实验数据可用。这项具有挑战性的任务的第一个目标是了解从粒子生长的地方建立稳定簇所需的机制。我们将研究粒子在表面的相互作用和扩散，以及附近粒子聚集的可行性。第二个主要目标是确定沿特定方向改变生长过程的参数，从而导致不同的颗粒形状，如片状，线状，片状。这些结构的反应性也将对常见分子（如分子氧和水）进行评估，因为这两种分子都存在于氧化反应和能量收集系统中。对分子氧的活化和解离的活性对于减少与氧化过程有关的工业废物是重要的。最后一个目标是将之前的结果结合到动力学模型中，以预测耐用的纳米结构在工业和能源技术中的应用。我们将结合一系列信息学工具，以有效和可靠的方式进行这项研究，这些工具提供纳米结构和支撑表面的原子级分辨率，并提供精确的细节，例如金属在支撑界面上的氧化状态。这些计算方法的结合将使我们能够研究控制金属颗粒成核、生长和形状的因素。结果将由我们在卡迪夫催化研究所和英国催化中心的实验合作伙伴进行验证。随着这项创新研究的成功，我们将详细了解控制支撑结构烧结的参数，从而导致诸如催化性能损失等不良性能。从这项研究中获得的知识适用于许多化学工业和学术研究人员。我们将把这项工作推广到广泛的领域。在卡迪夫催化研究所和与英国催化中心协会提供的协助下，我们将扩大和吸引公众参与，这将在这样一个主题的项目中非常重要。

Since modern society demands a higher quality of life base on efficient technology and clean energy, contemporary scientists focus on new materials with particular properties performing under environmental friendly conditions. Structures of less than 100 nano-meters in size present different properties from those of bulk materials. This scale has opened new research boundaries in a growing field, with wide-ranging implications. For example, current industries use nano-materials during the fabrication of a large number of everyday-products. In chemical industries these fine particles are commonly dispersed metals on support materials reducing the cost and waste yields during product manufacture. However, scientists follow primarily a ''mix and try'' approach for the synthesis because of the complexity of the formation process and stability nano-structures, which are affected by multiple parameters, such as temperature, pressure and metal precursor. Particle performance is dependent on their size and shape. Therefore we aim to identify computationally the thermodynamic and kinetic descriptors affecting the growth and stability of metal particles supported on specific surfaces. This project will allow us to unravel the effects of the support, the metal and the size of nano-particles while considering e.g. particles shape and diffusion across the surface, which will help to understand processes such as sintering and deactivation of the catalyst under working conditions. In particular, we propose to combine a number of late transition metals with well-characterised surfaces because of their importance in industrial catalysis and the extensive experimental data available. The first goal of this challenging task is to understand the mechanism needed to build stable clusters from where the particle will grow. We will study the particles' interaction and diffusion on the surface and the feasibility of nearby particles to agglomerate. The second major goal is to identify the parameters modifying the growth processes along particular directions leading to different particle shapes such as sheets, wires, flakes. The reactivity of these structures will also be evaluated against common molecules such as molecular oxygen and water as both are present in oxidation reactions and in energy harvesting systems. The activity towards the activation and dissociation of molecular oxygen is important for reducing industrial waste related with oxidation processes. The last goal is to combine the previous results in a kinetic model to predict a durable nano-structure with applications in industry and energy technologies.We will carry out this investigation in an effective and reliable way by combining a range of informatics tools which provide atomic-level resolution of the nano-structures and the supporting surface with accurate details e.g. oxidation state of the metal at the interface with the support. The combinations of these computational methods will allow us to study the factors controlling nucleation, growth and the shape of the supported metallic particles. The results will be validated by our experimental partners in the Cardiff Catalysis Institute and at the UK Catalysis Hub. With the success of this innovative research, we will provide detailed understanding of the parameters controlling the sintering of supported structures leading to undesirable properties e.g. loss of catalytic performance. The knowledge derived from this research is applicable to many chemical industries and academic researchers. We will disseminate the work across a wide range of fields. Within Cardiff Catalysis Institute and the assistance provided by association with the UK Catalysis Hub, we will outreach and engage the public which will be of importance in a project on such a topical theme.