Abstract The most energy-inefficient step in the oxygen evolution reaction (OER), which involves a complicated four-electron transfer process, limits the efficiency of the electrochemical water splitting. Here, well-defined Ni/Co3O4 nanoparticles coupled with N-doped carbon hybrids (Ni/Co3O4@NC) were synthesized via a facile impregnation-calcination method as efficient electrocatalysts for OER in alkaline media. Notably, the impregnation of the polymer with Ni and Co ions in the first step ensured the homogeneous distribution of metals, thus guaranteeing the subsequent in situ calcination reaction, which produced well-dispersed Ni and Co3O4 nanoparticles. Moreover, the N-doped carbon matrix formed at high temperatures could effectively prevent the aggregation and coalescence, and regulate the electronic configuration of active species. Benefiting from the synergistic effect between the Ni, Co3O4, and NC species, the obtained Ni/Co3O4@NC hybrids exhibited enhanced OER activities and remarkable stability in an alkaline solution with a smaller overpotential of 350 mV to afford 10 mA cm−2, lower Tafel slope of 52.27 mV dec−1, smaller charge-transfer resistance, and higher double-layer capacitance of 25.53 mF cm−2 compared to those of unary Co3O4@NC or Ni@NC metal hybrids. Therefore, this paper presents a facile strategy for designing other heteroatom-doped oxides coupled with ideal carbon materials as electrocatalysts for the OER.

中文翻译：

---

金属镍和钴氧化物与氮掺杂碳纳米球的协同效应用于高效析氧

摘要 析氧反应 (OER) 中能量效率最低的步骤涉及复杂的四电子转移过程，限制了电化学水分解的效率。在这里，通过简单的浸渍-煅烧方法合成了明确定义的 Ni/Co3O4 纳米粒子与 N 掺杂的碳杂化物（Ni/Co3O4@NC）作为碱性介质中 OER 的有效电催化剂。值得注意的是，第一步用Ni和Co离子浸渍聚合物确保了金属的均匀分布，从而保证了随后的原位煅烧反应，从而产生了分散良好的Ni和Co3O4纳米颗粒。此外，在高温下形成的 N 掺杂碳基体可以有效地防止聚集和聚结，并调节活性物种的电子构型。受益于 Ni、Co3O4 和 NC 物种之间的协同作用，获得的 Ni/Co3O4@NC 杂化物在碱性溶液中表现出增强的 OER 活性和显着的稳定性，较小的过电位为 350 mV，可提供 10 mA cm-2，更低的与一元 Co3O4@NC 或 Ni@NC 金属杂化物相比，Tafel 斜率为 52.27 mV dec-1，电荷转移电阻更小，双电层电容更高，为 25.53 mF cm-2。因此，本文提出了一种设计其他杂原子掺杂氧化物与理想碳材料作为 OER 电催化剂的简便策略。与一元 Co3O4@NC 或 Ni@NC 金属杂化物相比，具有较低的 52.27 mV dec−1 的 Tafel 斜率、较小的电荷转移电阻和较高的 25.53 mF cm−2 双层电容。因此，本文提出了一种设计其他杂原子掺杂氧化物与理想碳材料作为 OER 电催化剂的简便策略。与一元 Co3O4@NC 或 Ni@NC 金属杂化物相比，具有 52.27 mV dec-1 的较低 Tafel 斜率、较小的电荷转移电阻和较高的 25.53 mF cm-2 双层电容。因此，本文提出了一种设计其他杂原子掺杂氧化物与理想碳材料作为 OER 电催化剂的简便策略。