A Strategy Integrating "Electronic Modulation-Defect Engineering-Interfacial Water Reconstruction" for Designing...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient hydrogen production via anion exchange membrane (AEM) water electrolysis requires advanced electrocatalysts to overcome sluggish water dissociation kinetics.
• Current catalysts often face challenges in activity, cost-effectiveness, and long-term stability.

Purpose of the Study:

• To develop a highly active and cost-effective electrocatalyst for enhanced hydrogen evolution reaction (HER) in AEM water electrolysis.
• To investigate the synergistic effects of electronic modulation, defect engineering, and interfacial water reconstruction on catalyst performance.

Main Methods:

• Density functional theory (DFT) simulations guided the design strategy.
• Synthesis of fluorine-doped/phosphorus-vacancy-rich cobalt phosphide (F-CoPv) with a dandelion-like structure on carbon paper.
• Characterization using ab initio molecular dynamics simulations and X-ray absorption fine structure spectroscopy.

Main Results:

• F-CoPv/CP demonstrated superior HER activity with an overpotential (η₁₀₀) of 79 mV and excellent long-term stability (>600 h at 500 mA cm^-2).
• Fluorine doping restructured interfacial water and weakened O-H bonds by modulating electronic structure.
• Phosphorus vacancies exposed active cobalt sites, enhancing hydrogen desorption.
• An AEM electrolyzer (F-CoPv||NiFeO_x) achieved a low voltage of 2.098 V at 1000 mA cm^-2 at 60 °C.

Conclusions:

• The synergistic design strategy effectively enhances HER performance.
• F-CoPv/CP presents a promising electrocatalyst for efficient and stable hydrogen production in AEM water electrolysis.
• This approach offers new insights for designing high-performance HER catalysts.