两步水热法制备纳米花状Ni_(3)Fe/Ni_(3)S_(2)高效电催化剂促进碱性电解水析氧反应

Two-step hydrothermal preparing nanoflower-like Ni_(3)Fe/Ni_(3)S_(2) high-efficiency electrocatalysts to enhance oxygen evolution reaction in alkaline media

分别以Fe(NO_(3))_(3)·9H_(2)O和Na_(2)S·9H_(2)O作为Fe源和S源,用镍网(nickle mesh,NM)作为Ni源与支撑基底,采用两步水热法合成Ni_(3)Fe/Ni_(3)S_(2)析氧催化剂,通过X射线衍射、X射线光电子能谱、扫描电镜和透射电镜分析催化剂的显微组织与形貌,用电化学工作站进行电化学性能测试。结果表明:两步水热法合成的Ni_(3)Fe/Ni_(3)S_(2)催化剂为丰富立体的纳米花形貌,这种形貌可提升催化剂的空间利用率。Ni_(3)S_(2)暴露出高折射率的{210}晶面,与Ni_(3)Fe的(111)晶面产生协同效应,从而提升了催化活性。在1 mol/L的KOH溶液(25℃)中,10 mA/cm^(2)电流密度下Ni_(3)Fe/Ni_(3)S_(2)/NM的析氧过电位为229 mV,在5.35 mol/L的KOH溶液(80℃)中,600 mA/cm^(2)电流密度下的过电位为335 mV,且经6000圈循环伏安法循环后,过电位衰减率仅为2.39%,说明该催化剂具有良好的析氧性能和稳定性。

Ni_(3)Fe/Ni_(3)S_(2)oxygen evolution catalysts were synthesized by two-step hydrothermal method using Fe(NO_(3))_(3)·9H_(2)O and Na_(2)S·9H_(2)O as Fe source and S source,respectively,and nickel mesh(NM)as the Ni source and support substrate.The microstructure and morphology of the catalysts were analyzed by XRD,XPS,SEM,and TEM,and the electrochemical properties were tested by an electrochemical workstation.The results demonstrate that the Ni_(3)Fe/Ni_(3)S_(2)catalyst synthesized by the two-step hydrothermal method has rich three-dimensional nanoflower morphology,which enhances the spatial utilization of the catalyst.Ni_(3)S_(2)exposes a high refractive index{210}crystalline surface,which contributes to the synergistic effect with the(111)crystalline surface of Ni_(3)Fe to enhance the catalytic activity.The oxygen evolution overpotential is 229 mV at a current density of 10 mA/cm^(2)in 1 mol/L KOH(25℃),the overpotential is 335 mV for a current density of 600 mA/cm^(2)in 5.35 mol/L KOH(80℃),and the decay rate of the overpotential is only 2.39%after 6000 cyclic voltammetry cycles.It demonstrates that the catalyst has good oxygene evolution performance and stability.