Regulating Hydrogen/Oxygen Species Adsorption via Built‐in Electric Field ‐Driven Electron Transfer Behavior at the Heterointerface for Efficient Water Splitting.

Alkaline water electrolysis (AWE) plays a crucial role in the realization of a hydrogen economy. The design and development of efficient and stable bifunctional catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are pivotal to achieving high‐efficiency AWE. Herein, WC1‐x/Mo2C nanoparticle‐embedded carbon nanofiber (WC1‐x/Mo2C@CNF) with abundant interfaces is successfully designed and synthesized. Benefiting from the electron transfer behavior from Mo2C to WC1‐x, the electrocatalysts of WC1‐x/Mo2C@CNF exhibit superior HER and OER performance. Furthermore, when employed as anode and cathode in membrane electrode assembly devices, the WC1‐x/Mo2C@CNF catalyst exhibits enhanced catalytic activity and remarkable stability for 100 hours at a high current density of 200 mA cm−2 towards overall water splitting. The experimental characterizations and theoretical simulation reveal that modulation of the d‐band center for WC1‐x/Mo2C@CNF, achieved through the asymmetric charge distribution resulting from the built‐in electric field induced by work function, enables optimization of adsorption strength for hydrogen/oxygen intermediates, thereby promoting the catalytic kinetics for overall water splitting. This work provides promising strategies for designing highly active catalysts in energy conversion fields. [ABSTRACT FROM AUTHOR]