| 초록 |
Here, a hierarchical nanostructure composed of Ni:FeOOH nanosheets coupled with N-doped graphite foam (NGF) is demonstrated as a self-supported, metal-free electrocatalyst for highly efficient and durable water oxidation for the first time. A facile, one-step directional growth of catalytically active Ni:FeOOH nanosheets on highly conducting, three-dimensional (3D) NGF results in a fully integrated, hierarchical, nanostructured electrocatalyst with i) the high intrinsic activity of Ni:FeOOH, ii) the outstanding electrical conductivity of NGF, and iii) a well-defined porous structure with an enhanced active surface area. As a result, the self-supported, metal-free Ni:FeOOH/NGF electrocatalyst exhibit remarkable electrocatalytic activity for the oxygen evolution reaction (OER) in an alkaline solution with an overpotential of 214 mV at 10 mA/cm2, a high stability for over 60 h, a low Tafel slope of 36.2 mV dec-1, and capable of delivering a high current density of 300 mA/cm2 at an overpotential of 368 mV. In contrast to photodeposition, electrodeposition and hydrothermal methods for the formation/integration of oxyhydroxides, this facile solution strategy for designing an attractive and highly efficient structure with a highly active metal oxyhydroxide and the excellent conductivity of NGF provides a pathway to develop other earth-abundant electrocatalysts for a multitude of energy-conversion-device applications. |
