Efficient Alkaline Freshwater/Seawater Hydrogen Production via Heterogeneous N-Doped FeMoO4/Mo2N Rod-Shaped Electrocatalysts

Graphical A high-performance heterogeneous N-doped FeMoO 4 -Mo 2 N electrocatalyst was synthesized and applied as HER electrocatalyst in alkaline freshwater and alkaline seawater. Benefiting from the individual properties of both N-doped FeMoO 4 and Mo 2 N, the optimized FeMoO 4 -Mo 2 N electrocatalyst requires low overpotentials of 23 and 29 mV to afford 10 mA cm −2 in 1 M KOH freshwater and seawater electrolytes, respectively. Durable and efficient Fe-based electrocatalysts in alkaline freshwater/seawater electrolysis is highly desirable but persists a significant challenge. Herein, we report a durable and robust heterogenous nitrogen-doped FeMoO 4 /Mo 2 N rod-shaped catalyst on nickel foam (denoted NF@FMO/MN) affording hydrogen evolution reaction (HER) low overpotentials of 23/29 mV@10 mA cm −2 and 112/159 mV@100 mA cm −2 in both alkaline freshwater/seawater electrolytes, respectively. These results are significantly superior to the pristine FeMoO 4 catalyst. Theoretical calculations consistently reveals that the combination of N-FeMoO 4 and Mo 2 N effectively reduces water activation energy barrier, modulates the sluggish water-dissociation kinetics and accelerates the hydrogen adsorption process for efficient HER. The enhanced HER performance of the as-designed NF@FMO/MN catalyst is attributed to the in situ hetero-interfacial engineering between N-doped FeMoO 4 and Mo 2 N. This present work nurtures the progress of FeMo-based electrocatalysts in alkaline freshwater/seawater electrolysis.