A 3D hierarchical network derived from 2D Fe-doped NiSe nanosheets/carbon nanotubes with enhanced OER performance for overall water splitting

Designing an earth-abundant electrode material with high activity and durability is a major challenge for water splitting to produce clean and green hydrogen energy. In this study, we report a novel high-performance electrocatalyst derived from a unique three-dimensional hierarchical network of two-dimensional iron-doped nickel selenide nanosheets (2D Fe-doped NiSe NSs) and high-quality carbon nanotubes (CNTs) grown on a carbon paper substrate. The synergistic effects derived from Fe doping and interfering effects between 2D NSs and CNTs produce an enrichment of electroactive sites and good electrical conductivity, thereby significantly improving the electrocatalytic oxygen evolution activities. As a result, the catalyst requires an overpotential of only 282.7 mV to achieve 10 mA cm-2 in 1.0 M KOH electrolyte. An electrolyzer of Pt/C(-)//Fe-doped NiSe NSs/CNTs(+) demonstrates a cell voltage of 1.57 V and effective durability, superior to the state-of-the-art Pt/C(-)//RuO2/C(+) system (1.66 V) as well as recently reported catalysts. The achievements indicate a prospective catalyst for enhancing the OER in overall water splitting application.