铬掺杂黄钾铁矾微球的制备及OER性能研究

Research on Preparation and OER Properties of Chromium-doped Jarosite Microspheres

采用水热合成法制备出不同微观形貌的铬掺杂黄钾铁矾纳米球(KFe_(3-x)Cr_(x)(SO_(4))_(2)(OH)_(6))。利用XRD、SEM、FTIR和Raman对催化剂的微观结构及物理化学性质进行了表征,使用电化学工作站对样品进行电催化析氧性能(OER)测试。结果表明,Cr^(3+)取代部分Fe^(3+)的位置,随着摩尔比n(Fe^(3+)/Cr^(3+))的提高,黄钾铁钒由不规则的纳米颗粒转变成尺寸均一的纳米球。当n(Fe^(3+)/Cr^(3+))=2时,合成的KFe_(2)Cr_(1)(SO_(4))_(2)(OH)_(6)表面光滑、直径约为450~550 nm。当电流密度为10 mA/cm^(2)时,过电位为362 mV,塔菲尔斜率为73 mV·dec^(-1);恒电位测试20 h后电压无明显变化,基本趋于稳定。说明KFe_(2)Cr_(1)(SO_(4))_(2)(OH)_(6)微球表现出良好的OER催化活性和稳定性,为黄钾铁矾的应用提供了新的方向。

A series of chromium-doped jarosite nanospheres KFe_(3-x)Cr_(x)(SO_(4))_(2)(OH)_(6))with diverse microstructures were prepared by hydrothermal synthesis method.Microstructure and physicochemical properties of catalyst were investigated with the aid of XRD,SEM,FT-IR and Raman,and electrocatalytic oxygen evolution performance(OER)of samples were measured through electrochemical workstation.The results show that Cr^(3+)replaces part of Fe^(3+),and with the increase of the molar ratio of n(Fe^(3+)/Cr^(3+)),morphology of jarosite transforms from irregular nanoparticles to uniformly sized nanospheres.When n(Fe^(3+)/Cr^(3+))=2,the synthesized KFe_(2)Cr_(1)(SO_(4))_(2)(OH)_(6) is a nano-microsphere with smooth surface and diameter is about 450~550 nm.When the current density is 10 mA/cm^(2),the over potential is 362 mV and the Tafel slope is 73 mV·dec^(-1),meanwhile,the voltage does not change significantly after 20 h of constant potential test and basically stabilized,which indicates that KFe_(2)Cr_(1)(SO_(4))_(2)(OH)_(6) microsphere exhibits excellent OER catalytic performance and stability,and providing a new direction for application of jarosite.