Cost-effective copper-based materials with their abundant reserves, good electrical conductivity, and a wide range of redox properties that are promising for the electrochemical energy field, but they exhibit inertness and slow reaction kinetics for electrocatalysis. Therefore, improving the catalytic activity of Cu is prospective but still challenging. Herein, we developed a Ni and Fe-doped CuO/Cu₂O heterojunction catalyst with oxygen vacancies, which presented distinguished bifunctional catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. Remarkably, the adsorption/desorption energy of H₂O on surface of the catalyst had been definitely demonstrated via theoretical calculation and experiments, indicating that Fe, Ni bimetallic activated the inertness of the Cu-based materials. Fe doped corroded the Cu substrate and induced more oxygen vacancies, thereby increasing the electrochemically active area and ultimately enhancing the catalytic performance of the overall catalyst. Consequently, the cell voltage of Ni:Fe-CuO/Cu₂O catalysts for a current density of 10/20 mA·cm⁻² in an alkaline electrolyzer was just 1.51/1.69 V, and it exhibited an excellent stability. In addition, the cell voltage of the electrolyzer at of 10 mA·cm⁻² was just 1.30 V in simulated industrial hydrogen production via water electrolysis, and the current density can be as high as 1.8 A·cm⁻² at a voltage of 2.5 V. This study highlights the significant impact of electronic structure modulation and oxygen vacancies on copper-based catalysts, greatly enhancing the electrocatalytic activity of inert copper.

中文翻译：

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三元 Ni：Fe 活化惰性 Cu 基电催化剂作为用于水分解的高效双功能电催化剂


具有成本效益的铜基材料，具有丰富的储量、良好的导电性和广泛的氧化还原性能，在电化学能源领域很有前途，但它们在电催化方面表现出惰性和缓慢的反应动力学。因此，提高 Cu 的催化活性是有前景的，但仍然具有挑战性。在此，我们开发了一种具有氧空位的 Ni 和 Fe 掺杂 CuO/Cu₂O 异质结催化剂，它在碱性介质中对析氢反应 （HER） 和析氧反应 （OER） 表现出优异的双功能催化活性。值得注意的是，通过理论计算和实验明确证明了 H₂O 在催化剂表面的吸附/脱附能，表明 Fe、Ni 双金属活化了 Cu 基材料的惰性。Fe 掺杂腐蚀了 Cu 衬底并诱导了更多的氧空位，从而增加了电化学活性面积，最终增强了整体催化剂的催化性能。因此，在碱性电解槽中，当电流密度为 10/20 mA·cm⁻² 时，Ni：Fe-CuO/Cu₂O 催化剂的电池电压仅为 1.51/1.69 V，表现出优异的稳定性。此外，在模拟水电解工业制氢时，电解槽在 10 mA·cm⁻² 时的电池电压仅为 1.30 V，在 2.5 V 电压下电流密度可高达 1.8 A·cm⁻²。本研究强调了电子结构调制和氧空位对铜基催化剂的显着影响，大大提高了惰性铜的电催化活性。