Vanadium‐Incorporated CoP2 with Lattice Expansion for Highly Efficient Acidic Overall Water Splitting

Abstract A proton exchange membrane water electrolyzer (PEMWE) in acidic medium is a hopeful scenario for hydrogen production using renewable energy, but the grand challenge lies in substituting noble‐metal catalysts. Herein, a robust electrocatalyst of V−CoP 2 porous nanowires arranged on a carbon cloth is successfully fabricated by incorporating vanadium into the CoP 2 lattice. Structural characterizations and theoretical analysis indicate that lattice expansion of CoP 2 caused by V incorporation results in the upshift of the d‐band center, which is conducive to hydrogen adsorption for boosting the hydrogen evolution reaction (HER). Besides, V promotes surface reconstruction to generate a thicker Co 3 O 4 layer with an oxygen vacancy that enhances acid‐corrosion resistance and optimizes the adsorption of water and oxygen‐containing species, thus improving activity and stability toward the oxygen evolution reaction (OER). Accordingly, it presents a superior acidic overall water splitting activity (1.47 V@10 mA cm −2 ) to Pt−C/CC||RuO 2 /CC (1.59 V@10 mA cm −2 ), and remarkable stability. This work proposes a new route to design efficient non‐noble metal electrocatalysts for PEMWE.