Carbon encapsulated FeWO4-Ni3S2 nanosheets as a highly active catalyst for overall water splitting at large current density

Carbon encapsulated FeWO4-Ni3S2 with 3D spherical flower-like nanosheets structure as bifunctional catalyst for water splitting at large current density under simulated industrial condition. [Display omitted] •Carbon encapsulated FeWO4-Ni3S2/NF is prepared for the first time.•Carbon layer can adjust electronic structure to improve the stability and activity.•3D spherical flower-like nanosheets can efficiently enhance water splitting performance.•Great stability after testing for 100 h at 1,000 mA cm−2 under simulated industrial condition (6.0 M KOH solution, 60 °C). Exploring highly active and stable non-precious-metal catalysts for water splitting is significant, especially at large current density. Herein, a carbon-encapsulated FeWO4-Ni3S2 with 3D spherical flower-like nanosheets structure is prepared by solvothermal and calcination. It only needs low overpotentials for both oxygen evolution reaction (OER, η10 = 200 mV) and hydrogen evolution reaction (HER, η10 = 50 mV) in 1.0 M KOH. Besides, it could operate stably for 100 h at large current density of 1,000 mA cm−2 in industrial condition (6.0 M KOH, 60 °C) for overall water splitting (OWS), suggesting great industrial potential. Such good performance could be owing to: (1) Carbon-encapsulated structure can prevent the catalyst from corrosion in alkaline environment; (2) The modification of Ni3S2 to FeWO4 can enhance the intrinsic activity; (3) The unique 3D spherical flower-like nanosheets morphology could offer numerous active sites, and is beneficial for enhancing the stability by the desorption of bubbles. This work thus provides a strategy to manufacture decent performance non-precious-metal catalyst for water splitting.