Carbon capture and storage (CCS) is vital to climate change mitigation, and has application across the economy, in addition to facilitating atmospheric carbon dioxide removal resulting in emissions offsets and net negative emissions. This contribution reviews the state-of-the-art and identifies key challenges which must be overcome in order to pave the way for its large-scale deployment.
Understanding and controlling the formation of nanoparticles at the surface of functional oxide supports is critical for tuning activity and stability for catalytic and energy conversion applications. Here we use a latest generation environmental transmission electron microscope to follow the exsolution of individual nanoparticles at the surface of perovskite oxides, with ultra-high spatial and temporal resolution. Qualitative and quantitative analysis of the data reveals the atomic scale processes that underpin the formation of the socketed, strain-inducing interface that confers exsolved particles their exceptional stability and reactivity. This insight also enabled us to discover that the shape of exsolved particles can be controlled by changing the atmosphere in which exsolution is carried out and additionally, this could also produce intriguing heterostructures consisting of metal-metal oxide coupled nanoparticles. Our results not only provide insight into the in situ formation of nanoparticles, but also demonstrate the tailoring of nanostructures and nano-interfaces.
Metal nanoparticles prepared by exsolution at the surface of perovskite oxides have been recently shown to enable new dimensions in catalysis and energy conversion and storage technologies owing to their socketed, well-anchored structure. Here we show that contrary to general belief, exsolved particles do not necessarily re-dissolve back into the underlying perovskite upon oxidation. Instead, they may remain pinned to their initial locations, allowing one to subject them to further chemical transformations to alter their composition, structure and functionality dramatically, while preserving their initial spatial arrangement. We refer to this concept as chemistry at a point and illustrate it by tracking individual nanoparticles throughout various chemical transformations. We demonstrate its remarkable practical utility by preparing a nanostructured earth abundant metal catalyst which rivals platinum on a weight basis over hundreds of hours of operation. Our concept enables the design of compositionally diverse confined oxide particles with superior stability and catalytic reactivity.
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