High-Valence Mo Doping and Oxygen Vacancy Engineering to Promote Morphological Evolution and Oxygen Evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical water oxidation is crucial for sustainable energy but requires efficient, low-cost electrocatalysts.
• Developing such catalysts for alkaline media presents significant challenges.

Purpose of the Study:

• To design and synthesize novel molybdenum-doped cobalt oxide nanosheet arrays.
• To investigate the effects of doping and oxygen vacancies on electrocatalytic performance.
• To explore the potential of these materials for efficient water oxidation.

Main Methods:

• Combined strategies of metal doping (Mo) and oxygen vacancy engineering.
• Synthesis of Mo-doped cobalt oxide nanosheet arrays with varying morphologies.
• Electrochemical characterization, including overpotential measurements at 50 mA cm^-2.
• Density Functional Theory (DFT) calculations to understand catalytic mechanisms.

Main Results:

• Mo doping induced a morphological transformation from 1D to 3D nanostructures.
• Oxygen vacancies enhanced electronic conductivity and modulated electronic states.
• The optimal catalyst (MoCoO-3) showed a significantly reduced overpotential (288 mV) compared to the undoped counterpart (418 mV).
• DFT confirmed improved conductivity and optimized adsorption energies contributed to enhanced activity.

Conclusions:

• Mo-doped cobalt oxide nanosheet arrays with oxygen vacancies are highly effective electrocatalysts for water oxidation in alkaline media.
• The rational design combining doping and vacancy engineering offers a promising strategy for developing advanced electrocatalysts.
• The developed catalyst demonstrates superior performance in a two-electrode electrolyzer system.