Promoting water dissociation for efficient solar driven CO₂ electroreduction via improving hydroxyl adsorption.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrocatalysts are crucial for CO2 electroreduction.
• Understanding reaction mechanisms, especially water dissociation and surface species, is key but remains unclear.

Purpose of the Study:

• To promote protonation in CO2 electroreduction using oxygen vacancy engineering.
• To investigate the role of oxygen vacancies in enhancing formate production.

Main Methods:

• Oxygen vacancy engineering on Bi2O2CO3.
• Electrochemical measurements (Faradaic efficiency, partial current density).
• Electron spin resonance and in situ Raman spectroscopy with isotopic labeling.

Main Results:

• Achieved >90% Faradaic efficiency and 162 mA cm-2 partial current density for formate production.
• Oxygen vacancies accelerate water dissociation and reduce the CO2 electroreduction energetic span.
• Identified CO3* as the key surface species in formate formation.
• Solar-to-formate conversion efficiency reached 13.3% when coupled with a photovoltaic device.

Conclusions:

• Oxygen vacancy engineering is an effective strategy to enhance CO2 electroreduction to formate.
• Accelerated water dissociation and reduced energetic span contribute to improved performance.
• Fundamental understanding of reaction intermediates is achieved through advanced characterization techniques.