Kinetics of exsolution of metal nanoparticles from perovskite oxides and novel non-reductive exsolution mechanisms

The proposed experiments will study the temperature dependence of exsolution of metal nanoparticles from a perovskite support using in situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). These techniques were successfully employed to track the structural evolution and chemical state of the exsolving metal, respectively, upon exsolution at 800°C in 4% H2 from our optimized model systems based on La0.2Ca0.7Ti0.95Cu0.05O3−δ in our previous experiments at BM31. Time-resolved quantification of exsolution at different temperatures combined with Fick’s laws of diffusion will allow us to extract quantitative information of the diffusion and growth processes, supported by in situ STEM and DFT simulations. The proposed experiments will also elucidate a novel type of non-reductive exsolution process, i.e., exsolution of copper oxides in air/inert atmospheres, as such processes were indicated in our previous experiment.