KOH碱化处理对Fe3N纳米颗粒电催化制氢性能影响

采用KOH溶液在通电条件下对Fe₃N纳米颗粒表面改性的方法, 探究了碱化处理对Fe₃N纳米颗粒电催化性能的影响。采用XRD、TEM、EDX、XPS、拉曼光谱和傅立叶变换红外光谱对碱化前后的Fe₃N样品进行形貌和成分的表征, 采用时间电流曲线、LSV曲线、Tafel斜率、交流阻抗法和CV曲线对碱化前后的Fe₃N样品进行电催化制氢(HER)性能的分析。结果表明, 用KOH处理的Fe₃N样品, 平均晶粒尺寸由(80±10) nm缩小为(70±10) nm, 形状由破碎的链状结构变为椭圆形结构, 物相由ε-Fe₃N相部分转变为α-Fe₂O₃相; 尺寸、形貌和成分的改变, 使得碱化后的样品有更多的电催化活性位点暴露。由电流密度为10 mA/cm²的过电位0.429 V降为0.204 V, Tafel斜率由103 mV/dec降为95 mV/dec。过电势降低, 交流阻抗变小, 电化学活性面积增大, 表明KOH碱化处理后的样品电催化制氢的能力得到大大提高。

KOH Alkalized Fe3N Nanoparticles on Electrocatalytic Hydrogen Evolution Reaction

Surface modification of Fe₃N nanoparticles by KOH solution under electrification conditions was carried out, and effect of alkalization on the catalytic performance of Fe₃N nanoparticles was investigated. Morphology and composition of Fe₃N nanoparticles and alkalized Fe₃N nanoparticles were characterized by XRD, TEM, EDX, XPS, Raman spectra, and Fourier Transform Infrared spectroscopy. Electrocatalytic hydrogen evolution reaction (HER) performance of Fe₃N nanoparticles and alkalized Fe₃N nanoparticles was analyzed by time-current curve, linear sweep voltammetry, Tafel slope, AC impedance method, and CV curve. It was found that, for alkalized Fe₃N nanoparticles, their average grain sizes decreased from (80±10) nm to (70±10) nm. Their morphology changed from broken chain structure to elliptical structure, while their the phase changed partly from ε-Fe₃N to α-Fe₂O₃, which brought about more exposed electrocatalytic activity sites when compared with the Fe₃N before alkalization. Overpotential at 10 mA/cm² the alkalized Fe₃N nanoparticles was reduced from 0.429 V to 0.204 V and Tafel slope was reduced from 103 mV/dec to 95 mV/dec. Low opening voltage, small Tafel slope, low over-potential, small AC impedance and larg chemically active surface area were achieved by the alkalized Fe₃N nanoparticles, demonstrating that alkalized Fe₃N is a promising excellent electrocatalyst for water splitting.