Ultrafast Flame Exsolution of High-Density Metal Nanoparticles on Perovskite Oxides.

Kong, Dongjae; Li, Yuzhe; Ka, Dongwon; Ju, Kyoungjae; An, Jihwan; Zheng, Xiaolin · Nano Lett · 2026

basic_science · Level V

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Abstract

Exsolution of metal nanoparticles (NPs) is a powerful strategy for creating strongly attached catalysts for various energy-related applications, but the conventional exsolution methods based on thermal reduction are typically conducted at high temperatures for several hours to achieve sufficient NPs formation. Here, we introduce a new flame exsolution method that is exceptionally simple and rapid for decorating perovskite oxide surfaces with a high density of metal NPs under ambient conditions. By exposing perovskite oxides to a controlled fuel-rich methane-air flame (equivalence ratio, Φ = 1.45), we produced dense Ni NPs (∼500-550 μm<sup>-2</sup>) in just 1 min on both (La<sub>0.6</sub>Sr<sub>0.4</sub>)(Co<sub>0.2</sub>Fe<sub>0.8</sub>Ni<sub>0.05</sub>)O<sub>3-x</sub> (LSCF-5Ni) thin films and La<sub>0.43</sub>Ca<sub>0.37</sub>Ti<sub>0.94</sub>Ni<sub>0.06</sub>O<sub>3-x</sub> (LCTN) pellets. We further demonstrated that similar exsolution results were obtained for both perovskites using a common propane torch within 20 s, demonstrating the method's easy accessibility. This work establishes an ultrafast and transformative pathway to produce high-density metal NPs on perovskite oxides, overcoming the primary limitations of conventional exsolution techniques.