Single Ce atom-assisted oxygen vacancies as active and stable sites for CO₂ conversion

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Oxygen vacancies are key active sites for CO2 conversion.
• Engineering these vacancies for enhanced activity and stability, especially under harsh conditions (high temperature, H2S presence), remains challenging.
• Previous research has scarcely investigated vacancy promotion strategies.

Purpose of the Study:

• To engineer oxygen vacancies in MgO nanocrystals for improved CO2 conversion.
• To investigate the role of atomically dispersed Ce atoms in promoting these vacancies.
• To assess catalyst performance and stability under demanding reaction conditions.

Main Methods:

• Synthesis of defective MgO nanocrystals ( < 20 nm) with atomically dispersed Ce atoms.
• Characterization of catalyst structure and defect sites.
• Evaluation of catalytic performance for CO2 conversion using mechanistic studies, chemical kinetics, and theoretical modeling.

Main Results:

• Atomically dispersed Ce atoms significantly promote oxygen vacancies in MgO nanocrystals.
• The resulting single-atom-assisted oxygen vacancies (SA-Ov) catalysts exhibit high CO2 conversion rates.
• Exceptional stability was observed, even in the presence of 300 ppm H2S.

Conclusions:

• Single Ce atoms act as promoters for oxygen vacancies, enhancing CO2 adsorption and H2 activation.
• The SA-Ov mechanism is responsible for the high catalytic performance and stability.
• This work opens new avenues for designing advanced catalysts for CO2 conversion.