A layered CoSeO₃ pre-catalyst for electrocatalytic water oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic water oxidation is crucial for energy conversion.
• Surface reconstruction of electrocatalysts under anodic potential is a significant challenge affecting performance.
• Understanding the relationship between catalyst structure and its transformation is vital for designing stable and efficient catalysts.

Purpose of the Study:

• To investigate the influence of geometric structure on the surface reconstruction of cobalt selenite electrocatalysts during water oxidation.
• To compare the electrocatalytic performance and reconstruction behavior of two distinct cobalt selenite structures: CoSeO₃ and CoSeO₃·2H₂O.
• To elucidate the fundamental reasons behind the differential surface reconstruction observed in the studied cobalt selenites.

Main Methods:

• Synthesis of two cobalt selenite materials with different structures (CoSeO₃ and CoSeO₃·2H₂O).
• Electrochemical characterization including cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy.
• In-situ/operando characterization techniques (though not explicitly detailed, implied by studying reconstruction).
• Analysis of ion diffusion, surface interaction with hydroxide anions, and charge transfer kinetics.

Main Results:

• Layered CoSeO₃ exhibits cross channels that facilitate easier surface reconstruction compared to CoSeO₃·2H₂O.
• CoSeO₃ demonstrates a larger ion diffusion coefficient, increased surface contact with hydroxide anions, and faster charge transfer kinetics.
• These properties in CoSeO₃ contribute to its distinct surface reconstruction behavior and potentially improved electrocatalytic activity.

Conclusions:

• The geometric structure of cobalt selenites significantly influences their surface reconstruction behavior during electrocatalytic water oxidation.
• Layered CoSeO₃'s structure provides pathways for enhanced ion diffusion and surface interactions, leading to different reconstruction dynamics.
• This study offers a valuable paradigm for understanding and controlling pre-catalyst reconstruction by tailoring the geometric structure for improved electrocatalyst design.