溶胶-凝胶法制备纳米LaMnO3的电催化活性

摘要

Lanthanum manganate (LaMnO3) catalysts for zinc-air battery were prepared by surfactant PEG-2000 assisted sol-gel method.The structure and electrocatalytic activity of LaMnO3 catalysts were studied by thermogravimetry-differential scanning calorimeter(TG-DSC),XRD,Fourier transform infrared spectroscopy (FTIR),transmission electron microscope (TEM) and polarization curves.The optimum preparation process:the initial pH value was 6.5,the ratio of surface active agent to metal ions was 0.018∶ 1.000,calcined at 700 ℃ for 3 h.The prepared LaMnO3 was perovskite-type structure,the crystal forming temperature was about 450 ℃ and grain size was at the nanometer level,it had fine electrocatalytic activity for oxygen reduction.The air electrode with LaMnO3 as catalyst had the output current density of 0.165 A/cm2 at the potential of-600 mV (vs.Hg/HgO).%采用表面活性剂聚乙二醇-2000辅助溶胶-凝胶法,制备锌-空气电池催化剂锰酸镧(LaMnO3).通过热重-差示扫描量热(TG-DSC)法、XRD、傅里叶变换红外光谱(FTIR)、透射电子显微镜(TEM)和极化曲线,研究催化剂LaMnO3的结构和电催化活性.较优的制备工艺为:初始pH值为6.5,表面活性剂与金属离子物质的量比为0.018∶1.000,在700℃下煅烧3h.制备的LaMnO3为钙钛矿结构,晶体成型温度在450℃左右、晶粒尺寸处于纳米级别,具有良好的氧还原电催化活性.以LaMnO3为催化剂的电极在电位为-600 mV(vs.Hg/ HgO)时的输出电流密度为0.165 A/cm2.