Anodic Shock-Triggered Exsolution of Metal Nanoparticles from Perovskite Oxide,Journal of the American Chemical Society

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Anodic Shock-Triggered Exsolution of Metal Nanoparticles from Perovskite Oxide
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2022-04-26 , DOI: 10.1021/jacs.1c12970
Weiwei Fan ₁ , Baoming Wang ₂ , Rui Gao ₁ , Georgios Dimitrakopoulos _{1,

3} , Jiayue Wang ₁ , Xianghui Xiao ₄ , Lu Ma ₄ , Kai Wu ₅ , Bilge Yildiz _{1,

2} , Ju Li _{1,

2}

Affiliation

Nanoparticles decorated electrodes (NDEs) are useful in fuel cells, electrolyzers, water treatment, and chemical synthesis. Here, we show that by rapidly bringing a mixed ionic-electronic conductor outside its electrochemical stability window, one can achieve uniform dispersion of metallic nanoparticles inside its bulk and at the surface and improve its electrocatalytic performance when back under normal functional conditions. Surprisingly, this can happen under anodic as well as cathodic current/voltage shocks in an ABO₃ perovskite oxide, La_0.4Ca_0.4Ti_0.88Fe_0.06Ni_0.06O_3−δ (LCTFN), across a wide range of H₂/O₂ gas environments at 800 °C. One possible mechanism for bulk Fe⁰/Ni⁰ precipitation under anodic shock condition is the incomplete oxygen oxidation (O^2– → O^α–, 0 < α < 2), migration and escape of oxygen to interfaces, and “whiplash” transition-metal reduction due to low electronic conductivity. We show that both cathodic and anodic shocks can produce NDEs to enhance electrocatalytic performance, potentially improving the flexibility of this approach in practical devices.

中文翻译：

钙钛矿氧化物中金属纳米颗粒的阳极冲击触发外溶

纳米粒子装饰电极 (NDE) 可用于燃料电池、电解槽、水处理和化学合成。在这里，我们表明，通过将混合的离子电子导体快速置于其电化学稳定性窗口之外，可以实现金属纳米粒子在其内部和表面的均匀分散，并在返回正常功能条件下提高其电催化性能。令人惊讶的是，这可能在 ABO ₃钙钛矿氧化物 La _0.4 Ca _0.4 Ti _0.88 Fe _0.06 Ni _0.06 O _3-δ (LCTFN) 中的阳极和阴极电流/电压冲击下发生，在很宽的 H ₂ /O _2范围内800 °C 的气体环境。阳极冲击条件下块状 Fe ⁰ /Ni ^{0沉淀的一种可能机制是不完全的氧氧化（O}^2- → O ^α- , 0 < α < 2）、氧向界面迁移和逸出以及“鞭打”过渡-由于电子电导率低而导致金属还原。我们表明，阴极和阳极冲击都可以产生 NDE 以增强电催化性能，从而有可能提高这种方法在实际设备中的灵活性。

更新日期：2022-04-26

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