The electrocatalysis of the oxygen evolution reaction (OER) at the surface of oxidized metal electrocatalysts is highly dependent on the structure and composition of the surface oxide. Here, Au core‐ Co branched nanoparticles were synthesized using a cubic‐core hexagonal‐branch growth approach in a slow reductive solution synthesis, resulting in highly crystalline metallic hcp Co branches. Electrochemical surface oxidation of the Co branched nanoparticles resulted in formation of Co(OH)₂ that enable the formation of a higher number of active sites under OER conditions compared to Co₃O₄. Differently from polycrystalline spherical Au−Co core‐shell nanoparticles, the oxidized structure on the Co branched nanoparticle surface is retained with electrochemical cycling, resulting in improved OER activity and stability.

中文翻译：

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增加在高结晶度的Co支化纳米颗粒上的活性位点的形成，以改善氧释放反应的电催化作用

氧化的金属电催化剂表面的氧释放反应（OER）的电催化高度依赖于表面氧化物的结构和组成。在这里，Au核-Co支链纳米粒子是通过立方核六角形分支生长方法以缓慢还原溶液合成的方式合成的，从而产生了高度结晶的金属hcp Co支链。Co支化纳米粒子的电化学表面氧化导致形成Co（OH）₂，与Co ₃ O ₄相比，该化合物能够在OER条件下形成更多数量的活性位点。与多晶球形Au-Co核壳纳米颗粒不同，Co支化纳米颗粒表面的氧化结构通过电化学循环得以保留，从而提高了OER活性和稳定性。