NanoFunC - Controlling Selectivity via Nanostructuring of Multifunctional Model Catalysts

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A future vision is the rational design of nanostructured catalyst materials with improved selectivity and activity. Towards this aim we explore the potential of fundamental model studies in CO2-reforming and CO2-OCM (oxidative coupling) of methane. Inspired by empirical approaches involving multifunctional materials, novel multiply nanostructured model catalysts are developed, which integrate, for instance (a) redox sites (e.g. CeO2) (b) basic centres (e.g. MgO, BaO), (c) metallic sites (e.g. Rh, Pt) and (d) support sites (e.g. Al2O3) in a well-defined environment. The three-step strategy of this project is based on a unique portfolio of experimental techniques: (i) Multiply nanostructured model surfaces are prepared under UHV (ultrahigh vacuum) conditions and their structural and chemical properties (particle structure, size, density, defects, boundary sites, composite/isolated nanoparticles, etc.) are characterized in detail using UHV microscopies and a broad spectrum of surface science methods. (ii) The structural properties are correlated with elementary reaction kinetics, energetics and dynamics of selected key steps at the microscopic level, applying MB (molecular beam) techniques and time-resolved surface spectroscopies. (iii) Finally, the information on nanostructure and elementary kinetics is combined with systematic and quantitative kinetic studies, applying multi MB methods, reactor methods, and time-resolved in-situ surface-spectroscopies from UHV to ambient conditions (“pressure gap”). In all three steps, the experimental studies are closely linked with high-level DFT (density functional theory) calculations employing advanced recently developed realistic models of nanostructured reaction systems, which allow for adequate description of the latter.The aim of the project is to develop microscopically well-founded mechanistic models, which provide a consistent description of the complete reaction system. These models will explicitly incorporate kinetic control by nanostructuring and the mutual interplay of kinetic effects in multiply nanostructured systems. With respect to CO2-reforming and CO2-OCM the optimization of selectivity by nanostructuring is of primary interest, including aspects such as e.g. controlling deactivation by kinetically suppressing carbon formation. Beyond strong contribution to these specific target reactions, the project will result in conceptual insights guiding future design strategies towards tailor-made nanostructured catalysts.