High-performance multidimensional-structured N-doped nickel modulated Mo2N/FeOxNy bifunctional electrocatalysts for efficient alkaline seawater splitting

Realizing effective alkaline water/seawater electrolysis through efficient hydrogen and oxygen evolution reaction (HER and OER) electrocatalysts is demanding but attracts significant task. Herein, a novel NNNF@Mo2N/FeOxNy electrocatalyst comprising of Mo2N/FeOxNy interfacial rod-shaped structure on nitrogen-doped nickel nanosheets modified nickel foam (NF) (denoted NNNF) with remarkable HER and OER catalytic performance is reported. The nanosheet-rod structure coupled with multidimensional interfacial boundaries enriches the optimized NNNF@Mo2N/FeOxNy catalyst with rich active sites. As a result, the as-prepared NNNF@Mo2N/FeOxNy catalyst demands low overpotentials of 22/130 mV and 28/142 mV to drive current densities of 10/100 mA cm−2 for the HER, 222/348 mV and 239/361 mV for the OER in 1 M alkaline freshwater/seawater electrolytes, respectively. The catalyst also reveals excellent HER and OER stability for 100 h at a constant high current density of 100 mA cm−2 in both electrolytes. The catalyst also acts as bifunctional catalyst in overall water electrolytic devices requiring low overall voltages of 1.42/1.47 V@20 mA cm−2 in alkaline freshwater/seawater electrolytes, as well as considerable voltages of 1.50/1.81 V@100/500 mA cm−2 in 6 M KOH seawater electrolyte at 60 °C for industrial conditions.