高效析氧电催化剂Co3O4@NiMn-LDH异质结构阵列的制备

我们合理设计和制备了一种新型的高性能析氧电催化剂——泡沫镍负载Co_3O_4@NiMn-LDH(层状双金属氢氧化物)三维异质结构阵列(Co_3O_4@NiMn-LDH/NF)。这种基于泡沫镍基底的三维异质结构催化剂经简单的两步水热反应即可制得。对比Co_3O_4、NiMn-LDH及传统RuO2催化剂,所制备的Co_3O_4@NiMn-LDH/NF催化剂展示出更优异的电催化析氧性能。在1 mol·L~(-1)KOH溶液中,电流密度为50 mA·cm~(-2)时的过电势仅为282 mV,塔菲尔斜率为64 mV·dec~(-1)。通过有效的界面工程设计,使异质结构陈列Co_3O_4@NiMn-LDH发挥出Co_3O_4和NiMn-LDH各自优异的电催化性能。其中,基于泡沫镍基底生长的活性组分Co_3O_4纳米线阵列作为中间核支撑结构,保持了良好的空隙率,不仅有利于暴露更多的活性位点,而且有利于电解液的扩散和气体产物的释放;而依附于Co_3O_4纳米线阵列上的NiMn-LDH异质结构纳米片层则富有更多的亲水性基团,使得活性位点更易与水结合,从而促进氧析出反应的进行。

Preparation of Co3O4@NiMn-LDH Heterostructured Arrays as Efficient Oxygen Evolution Electrocatalyst

In this paper, we report the rational design and preparation of a new type of high-performance oxygen evolution electrocatalyst, namely 3D heterostructured Co₃O₄@NiMn-LDH (layered double metal hydroxide) arrays supported on Ni foam (Co₃O₄@NiMn-LDH/NF). It was prepared via facile two-step hydrothermal reactions. Compared with Co₃O₄, NiMn-LDH and traditional RuO₂ electrocatalysts, the as-prepared Co₃O₄@NiMn-LDH/NF presents better electrocatalytic oxygen evolution performance, achieving a low overpotential of 282 mV at 50 mA·cm^-2 with a Tafel slope of 64 mV·dec^-1 in 1 mol·L^-1 KOH solution. Through designing effective interface engineering, the Co₃O₄@NiMn-LDH/NF combines synergistically the excellent electrocatalytic activity of Co₃O₄ and NiMn-LDH. The Co₃O₄ nanowire array based on Ni foam as a core structure with abundant void spaces not only exposes more active sites, but also ensures easy diffusion of electrolyte and fast release of gas products. And the NiMn-LDH nanosheets on the Co₃O₄ nanowire array provide rich hydrophilic groups and active sites for easy access of water molecules, thus facilitating efficient oxygen evolution reaction.