微纳电子技术

以先水热后硫化的方法制备出基于石墨毡基底的镍钴基化合物(NiCo_2O₄/GF和NiCo_2S₄/GF)电极,探究不同水热温度对电极的催化特性的影响。通过扫描电子显微镜(SEM)、能量色散X射线光谱仪(EDS)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对样品表面形貌、结构、晶向及元素分布进行分析。通过循环伏安(CV)曲线、线性扫描伏安(LSV)曲线、Tafel曲线和电化学阻抗谱(EIS)研究其双功能催化特性。研究发现,水热温度130℃下,NiCo_2O₄/GF电极在析氢反应(HER)中表现优异,在10 mA·cm^-2的电流密度下具有52.2 mV的低过电位和87.6 mV·dec^-1的Tafel斜率;另外,水热温度140℃下,NiCo_2S₄/GF电极在析氧反应(OER)中也展示出卓越的性能,在10 mA·cm^-2的电流密度下具有215 mV的较低过电位和85.2 mV·dec^-1的Tafel斜率。同时两种电极的稳定性都表现极佳,在5 000次的CV循环中总的电荷转移电阻基本不变。结果表明,镍钴基化合物表现出更好的双功能电催化特性。

The nickel-cobalt-based compound electrodes(NiCo_2O₄/GF and NiCo_2S₄/GF) based on graphite felt were prepared by the method of first hydrothermal and then vulcanized to explore the influence of different hydrothermal temperatures on the catalytic properties of the electrodes. The scanning electron microscope(SEM), energy dispersive X-ray spectrometer(EDS), X-ray diffractometer(XRD) and X-ray photoelectron spectrometer(XPS) were performed to analyze the sample surface morphology, structure, crystal orientation and element distribution. The cyclic voltammogram(CV) curve, linear sweep voltammetry(LSV) curve, Tafel curve and electrochemical impedance spectroscopy(EIS) were used to study their bifunctional catalytic properties. It is found that the NiCo_2O₄/GF electrode at a hydrothermal temperature of 130 ℃ performs well in the hydrogen evolution reaction(HER), with a low overpotential of 52.2 mV and a Tafel slope of 87.6 mV·dec^-1 at a current density of 10 mA·cm^-2. In addition, the NiCo_2S₄/GF electrode at a hydrothermal temperature of 140 ℃ also shows excellent performance in the oxygen evolution reaction(OER), with a low overpotential of 215 mV and a Tafel slope of 85.2 mV·dec^-1 at a current density of 10 mA·cm^-2. At the same time, the stability of the two electrodes is excellent, and total charge-transfer resistance is basically unchanged during 5 000 CV cycles. The results show that nickel-cobalt-based compounds provide a new idea to better display bifunctional electrocatalytic properties.