Exploring advanced electrocatalysts for the hydrazine oxidation reaction (HzOR) could expedite the applications of direct hydrazine fuel cells (DHzFCs) for zero-carbon economics. Herein, we report a remarkable HzOR electrocatalyst based on low-coordinated Co arrays supported on Cu foam (p-Co/CF). The low-coordinated Co arrays were synthesized by the reduction of the Co(OH)F precursor with H₂ plasma to induce numerous few-atom vacancies, producing low-coordinated surface Co atoms as catalytic active sites. The as-prepared p-Co/CF electrode exhibits a low onset potential of −0.15 V (vs. RHE) and a small Tafel slope of 8.83 mV dec⁻¹ in 0.05 M N₂H₄/1 M KOH electrolyte, which are superior to those of most reported electrocatalysts toward the HzOR. Density functional theory (DFT) calculations have been employed to elucidate the HzOR process on metallic Co catalysts, suggesting that the improved catalytic activity would be attributed to the weakened adsorption of N₂H₃* on low-coordinated Co sites. Benefited by the superior catalytic activity of p-Co/CF, a prototype DHzFC has been demonstrated to deliver a high open circuit voltage of 1.1 V and a maximal power density of 186 mW cm⁻² at ambient temperatures. This work provides guidance for designing high-performance non-noble metal electrocatalysts toward viable direct hydrazine fuel cells.

中文翻译：

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用于高效肼电氧化的低配位钴阵列

探索用于肼氧化反应 (HzOR) 的先进电催化剂可以加快直接肼燃料电池 (DHzFC) 在零碳经济中的应用。在这里，我们报告了一种基于铜泡沫（p-Co/CF）上的低配位 Co 阵列的卓越的 HzOR 电催化剂。低配位Co阵列是通过用H ₂等离子体还原Co(OH)F前驱体以诱导大量少原子空位，产生低配位表面Co原子作为催化活性位点来合成的。所制备的 p-Co/CF 电极在 0.05 MN ₂ H ₄中表现出 -0.15 V 的低起始电位（相对于RHE）和 8.83 mV dec ^-1的小 Tafel 斜率。/1 M KOH 电解质，优于大多数报道的用于 HzOR 的电催化剂。密度泛函理论 (DFT) 计算已用于阐明金属 Co 催化剂上的 HzOR 过程，表明催化活性的提高归因于 N ₂ H ₃ * 在低配位 Co 位点上的吸附减弱。得益于 p-Co/CF 的优异催化活性，原型 DHzFC 已被证明可在环境温度下提供 1.1 V 的高开路电压和 186 mW cm ^{-2的最大功率密度。}这项工作为设计高性能非贵金属电催化剂以实现可行的直接肼燃料电池提供了指导。