Metastable nanostructures are kinetically trapped in local energy minima featuring intriguing surface and material properties. To unleash their potential, there is a need for non-equilibrium processes capable of stabilizing a large range of crystal phases outside thermodynamic equilibrium conditions by closely and flexibly controlling atomic reactant composition, spatial temperature distribution and residence time. Here, we demonstrate the capture of metastable pseudo-binary metal oxides at room temperature with scalable combustion-aerosol processes. By a combination of X-ray diffraction, electron microscopy and online flame characterization, we investigate the occurrence of metastable CoCu2O3 with controlled crystal size (4-16 nm) over thermodynamically stable CuO and Co3O4. Immediate practical impact is demonstrated by exceptional sensing and catalytic performance for air pollutant detection (e.g., 15 parts-per-billion benzene). This approach can be extended to various binary, ternary and high entropy oxides with even more components to access novel materials also promising for actuators, energy storage or solar cells.
@article{arxiv.2406.10588,
title = {Metastable CoCu$_2$O$_3$ for molecular sensing and catalysis},
author = {Matteo D'Andria and Tiago Elias Abi-Ramia Silva and Edoardo Consogno and Frank Krumeich and Andreas T. Guentner},
journal= {arXiv preprint arXiv:2406.10588},
year = {2024}
}