This proposal aims to develop a generic synthesis approach for core-shell nanoparticles by unravelling the relevant mechanisms. Core-shell nanoparticles have high potential in heterogeneous catalysis, energy storage, and medical applications. However, on a fundamental level there is currently a poor understanding of how to produce such nanostructured particles in a controllable and scalable manner.The main barriers to achieving this goal are understanding how nanoparticles agglomerate to loose dynamic clusters and controlling the agglomeration process in gas flows during coating, such that uniform coatings can be made. This is very challenging because of the two-way coupling between agglomeration and coating. During the coating we change the particle surfaces and thus the way the particles stick together. Correspondingly, the stickiness of particles determines how easy reactants can reach the surface.Innovatively the project will be the first systematic study into this multi-scale phenomenon with investigations at all relevant length scales. Current synthesis approaches – mostly carried out in the liquid phase – are typically developed case by case. I will coat nanoparticles in the gas phase with atomic layer deposition (ALD): a technique from the semi-conductor industry that can deposit a wide range of materials. ALD applied to flat substrates offers excellent control over layer thickness. I will investigate the modification of single particle surfaces, particle-particle interaction, the structure of agglomerates, and the flow behaviour of large number of agglomerates. To this end, I will apply a multidisciplinary approach, combining disciplines as physical chemistry, fluid dynamics, and reaction engineering.