The FeOOH Decorated Fe-Doped Nickel Selenide Hierarchical Array for High-Performance Water Oxidation

For production hydrogen with water electrolysis to promote the development of a hydrogen-energy economy, it is crucial to develop efficient, durable, and non-noble metal electrocatalysts for the oxygen evolution reaction (OER). Transition metal selenides have been considered as promising alternatives for OER due to their excellent conductivity. Herein, FeOOH-decorated Fe-doped NiSe on NiFe foam (FeOOH@Fe-NiSe@NiFe) was synthesized with an autologous growth approach, where the NiFe foam was used as an Fe and Ni resource. The FeOOH@Fe-NiSe@NiFe electrode exhibits excellent electrocatalytic performance with an overpotential of 224 mV at 10 mA cm–2, a small Tafel slope of 52.67 mV dec–1, and remarkable stability. Results confirm that the morphology and electronic structure of designed electrocatalysts can be significantly tailored due to the introduction of Fe. The designed FeOOH@Fe-NiSe@NiFe electrode also possesses superior aerophobicity, which ensures fast mass transfer during water splitting processes. As a result, the electrocatalytic activity is improved remarkably. In addition, the actual active sites of designed electrocatalysts were also systematically investigated. Experimental studies demonstrate that the Fe/NiOOH on the surface of Fe-NiSe, which in situ converses from Fe-NiSe, can serve as the intrinsic active sites toward the OER. Thus, this work can provide a new methodology to designing durable and efficient electrocatalysts.