Self-Etching Synthesis of Superhydrophilic Iron-Rich Defect Heterostructure-Integrated Catalyst with Fast Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient catalysts is key for electrocatalytic water oxidation and large-current water splitting.
• Metal defects, hydrophilicity, and grain boundaries are critical catalyst properties.

Purpose of the Study:

• To synthesize and characterize a novel heterostructure catalyst for enhanced water oxidation and splitting.
• To investigate the role of metal defects, hydrophilicity, and grain boundaries in catalyst performance.

Main Methods:

• Utilized pH-controlled etching and gas-phase phosphating to create a flower-like Ni2P-FeP4-Cu3P modified nickel foam heterostructure.
• Characterized catalyst properties including hydrophilicity, defect concentration, and grain boundaries.
• Evaluated electrocatalytic performance for water oxidation and overall water splitting in an electrolyzer.

Main Results:

• The synthesized catalyst exhibits pronounced hydrophilicity and a high concentration of Fe defects.
• Achieved low overpotentials (156 mV at 10 mA/cm2, 210 mV at 100 mA/cm2) for water oxidation with 200h stability.
• Demonstrated excellent overall water splitting performance (400 mA/cm2 at 1.73 V) and 60h stability at 500 mA/cm2.
• Identified high-valence oxyhydroxides/phosphides of Ni, Fe, and Cu as active species.

Conclusions:

• Abundant Fe defects, strong hydrophilicity, and numerous grain boundaries synergistically enhance electrocatalytic water oxidation kinetics.
• The novel catalyst offers a promising pathway for efficient and stable large-current water splitting applications.