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

The work-function difference-induced formation of BEF can drive the asymmetrical charge distribution of heterostructure WC_1-x/Mo₂C@CNF catalysts through electronic transfer behaviors and manipulate the d band structure of active sites, thereby optimizing intermediate adsorption energy and accelerating reaction kinetics of the overall water splitting process.

Abstract

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, WC_1-x/Mo₂C nanoparticle-embedded carbon nanofiber (WC_1-x/Mo₂C@CNF) with abundant interfaces is successfully designed and synthesized. Benefiting from the electron transfer behavior from Mo₂C to WC_1-x, the electrocatalysts of WC_1-x/Mo₂C@CNF exhibit superior HER and OER performance. Furthermore, when employed as anode and cathode in membrane electrode assembly devices, the WC_1-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 WC_1-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.

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