High-Density W Single Atoms in Two-Dimensional Spinel Oxide Break the Structural Integrity for Enhanced Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Oxygen evolution reaction (OER) catalyst performance relies on active site density and intrinsic properties, presenting design challenges.
• Developing efficient and robust OER catalysts is crucial for energy conversion technologies.
• Existing catalysts like Ni and NiFe have limitations in activity and stability.

Purpose of the Study:

• To develop a general strategy for preparing oxide-based 4d/5d transition metal single-atom 2D materials for OER.
• To investigate the use of oxygen vacancies for anchoring single atoms and enhancing catalyst performance.
• To evaluate the catalytic activity and stability of the synthesized W-Co3O4 material.

Main Methods:

• A novel oxygen-vacancy anchoring strategy using Keggin-structure polyoxometalate decomposition.
• In situ adherence of tungsten (W) single atoms to metal (Co, Fe, Ni) hydroxide surfaces.
• Annealing to form ultrathin 2D materials (e.g., W-Co3O4) and characterization of their structure and properties.

Main Results:

• Uniform distribution of W single atoms anchored by oxygen vacancies in M(OH)x.
• W-Co3O4 exhibits a 5-7 times higher specific surface area than pure Co3O4.
• The catalyst achieves a low overpotential (η10) of 261 mV and excellent stability (>290 h) in alkaline media.

Conclusions:

• The oxygen-vacancy anchoring strategy effectively stabilizes single atoms and enhances catalyst performance.
• W-Co3O4 demonstrates superior intrinsic activity and structural integrity for OER compared to pure Co3O4.
• This approach offers a promising pathway for designing highly efficient and robust OER catalysts.