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

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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.