Challenging thermodynamics: combining immiscible elements in a single-phase nano-ceramic.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38326434.
- Also identified by DOI 10.1038/s41467-024-45413-w and PMC identifier 10850329.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The Hume-Rothery rules governing solid-state miscibility limit the compositional space for new inorganic material discovery. Here, we report a non-equilibrium, one-step, and scalable flame synthesis method to overcome thermodynamic limits and incorporate immiscible elements into single phase ceramic nanoshells. Starting from prototype examples including (NiMg)O, (NiAl)O<sub>x</sub>, and (NiZr)O<sub>x</sub>, we then extend this method to a broad range of Ni-containing ceramic solid solutions, and finally to general binary combinations of elements. Furthermore, we report an "encapsulated exsolution" phenomenon observed upon reducing the metastable porous (Ni<sub>0.07</sub>Al<sub>0.93</sub>)O<sub>x</sub> to create ultra-stable Ni nanoparticles embedded within the walls of porous Al<sub>2</sub>O<sub>3</sub> nanoshells. This nanoconfined structure demonstrated high sintering resistance during 640 h of catalysis of CO<sub>2</sub> reforming of methane, maintaining constant 96% CH<sub>4</sub> and CO<sub>2</sub> conversion at 800 °C and dramatically outperforming conventional catalysts. Our findings could greatly expand opportunities to develop novel inorganic energy, structural, and functional materials.