空心ZnMn2O4纳米球和纳米立方体的室温合成及氧还原催化性能

摘要

This paper reported the room-temperature synthesis of ZnMn2O4 spinels. The formation of hollow ZnMn2O4 with nanospheres and nanocubes structures was accomplished by reduction of amorphous MnO2 precursors using NaBH4 in aqueous solution containing Zn2+. The structure, morphology, composition and surface properties of the as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy ( SEM ), transmission electron microscopy ( TEM ) and brunauer-emmett-teller (BET)measurements. It is found that the sizes of as-prepared hollow ZnMn2O4 nanospheres and nanoeubes are about 400-700 nm with wall thickness of 40 nm, and that the walls of the hollow ZnMn2O4 nanostructures are densely aggregated by tiny particles with diameter of 5-7 nm. Furthermore, the activities of oxygen reduction reaction(ORR) in alkaline media of the as-prepared hollow ZnMn2O4 nanospheres and nanocubes were also investigated. The experimental results show that the hollow ZnMn2O4 nanospheres exhibit better electrocatalysis performance with a high current density and an electron transferred number of 3. 5, indicating their promising application as low-cost catalysts for ORR.%室温下在含有Zn2+的溶液中,以空心结构的MnO2为前驱体,使用NaBH,还原剂合成了尖晶石型ZnMn2O4纳米空心球和纳米空心立方体.通过XRD,SEM,TEM 和BET 等测试手段对合成产物的结构、形貌、组成和表面积进行表征.结果表明,所制备的空心结构ZnMn2O4纳米球和纳米立方体的尺寸为400～700 am,空心结构的壳层是由粒径为5～7 nm 的颗粒紧密堆积而形成的,厚度约为40 nm.研究了所制备的空心结构纳米ZnMn2O4在碱性溶液中的氧还原电催化性能,结果显示,相对于ZnMn2O4纳米空心立方体,ZnMn2O4纳米空心球在氧还原反应中具有较大的电流密度和较高的电子转移数(n=3.5),表现出较好的氧还原电催化性能.