Defect and doping synergistic optimization for efficient and durable alkaline seawater hydrogen production

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Seawater electrolysis is crucial for freshwater and hydrogen production.
• Chloride ions in seawater cause electrode degradation and parasitic reactions, limiting stability.
• Developing robust electrocatalysts for direct seawater splitting is essential.

Purpose of the Study:

• To design and synthesize a highly efficient and stable electrocatalyst for seawater electrolysis.
• To investigate the synergistic effects of vanadium doping and oxygen vacancies on cobalt oxide performance.
• To address the challenges posed by chloride ions in alkaline seawater electrolysis.

Main Methods:

• Hydrothermal synthesis of nanoflower-structured Co3O4.
• Controlled annealing to introduce vanadium (V) doping and oxygen vacancies (Ov).
• Electrochemical characterization of the V-Co3O4(Ov)-250 catalyst in freshwater and seawater.

Main Results:

• The V-Co3O4(Ov)-250 catalyst exhibited low overpotentials for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline seawater.
• Achieved a low cell voltage of 1.68 V at 100 mA cm-2 for seawater electrolysis.
• Demonstrated excellent long-term stability (>100 h) in alkaline seawater.
• Theoretical analysis confirmed enhanced catalytic activity due to V doping and Ov synergy.

Conclusions:

• Vanadium doping and oxygen vacancies synergistically enhance the catalytic activity and stability of Co3O4 for seawater electrolysis.
• The developed catalyst offers a promising non-precious metal alternative for efficient hydrogen production from seawater.
• This work provides a viable strategy for overcoming the limitations of direct seawater electrolysis.