Mo掺杂柔性高熵合金析氧反应电催化性能研究

Electrocatalytic Oxygen Evolution Performance of Mo-Doped Flexible High-Entropy Alloys

摘要:

析氧反应（oxygen evolution reaction，OER）的动力学迟缓严重制约了水分解与金属-空气电池的实际应用效能。采用磁控溅射技术在碳布衬底上成功制备了系列CrFeCoNiMo_x（x=0，0.2，0.5，1）柔性高熵合金一体化电极，系统研究了Mo掺杂量对其析氧反应电催化性能的影响。实验结果表明，适量Mo掺杂能显著提升电极的OER活性，其中CrFeCoNiMo_0.5表现最优，达到10 mA/cm²电流密度仅需过电位212 mV，Tafel斜率为37.4 mV/dec，且在100 mA/cm²高电流密度下稳定运行140 h未见明显衰减。通过XPS、TEM、原位拉曼等表征方法发现，Mo掺杂可有效调节Fe、Ni等3d金属的电子结构，提高了其氧化态，促进了电极表面非晶化重构，增强了对反应中间体的吸附能力。结合密度泛函理论（density functional theory，DFT）的计算表明，Mo掺杂优化了反应路径，降低了氧空位形成能垒。该研究为柔性高熵合金电极在能源转换领域的应用提供了实验依据与理论支持。

Abstract:

The intrinsically sluggish kinetics of the oxygen evolution reaction (OER) severely restricts the practical efficiencies of water splitting and metal-air batteries. In this research, a series of flexible CrFeCoNiMo_x (x=0, 0.2, 0.5, 1) high-entropy alloy (HEA) monolithic electrodes were directly fabricated on carbon cloth by magnetron sputtering, and the influence of Mo doping content on their OER electrocatalytic performance was investigated. The results show that the appropriate Mo doping can significantly enhance the OER activity of the electrode. Among the prepared electrodes, CrFeCoNiMo_0.5 exhibits the highest catalytic activity, delivering a current density of 10 mA/cm² at an overpotential of only 212 mV with a Tafel slope of 37.4 mV/dec. Moreover, the electrode operates stably at 100 mA/cm² for 140 h without noticeable degradation. XPS, TEM and in-situ Raman analyses reveal that Mo doping tailors the electronic structure of 3d metals (Fe, Ni), elevates their oxidation states and promotes surface amorphization/reconstruction, thereby strengthening the adsorption of reaction intermediates. Density functional theory (DFT) calculations further demonstrate that Mo doping optimizes the reaction pathway and lowers the energy barrier for oxygen-vacancy formation. These findings provide both experimental evidence and theoretical support for the application of flexible HEA electrodes in advanced energy-conversion devices.