CO₂ Adsorption and Photocatalytic Reduction Mechanisms on TiO₂‑Terminated CaTiO₃(100): A Density Functional Theory...

Area of Science:

• Materials Science
• Catalysis
• Computational Chemistry

Background:

• Photoreduction of carbon dioxide (CO2) is crucial for mitigating global warming.
• Efficient photocatalysts are needed to improve CO2 conversion efficiency and selectivity.
• Calcium titanate (CaTiO3) is a promising semiconductor catalyst for CO2 photoreduction.

Purpose of the Study:

• Investigate the reaction mechanisms for CO2 photoreduction on CaTiO3.
• Determine the pathways for producing valuable byproducts like HCOOH, CO, CH3OH, and CH4.
• Understand the factors influencing the selectivity of different products.

Main Methods:

• First-principles electronic structure calculations.
• Analysis of adsorption, activation, and reduction reactions.
• Focus on TiO2-terminated CaTiO3 (100) surface.

Main Results:

• CO2 activation via electron transfer forms a CO2 radical anion (CO2·−).
• Formate (HCOO−) intermediate is formed, but subsequent hydrogenation to HCOOH is energetically unfavorable.
• CO production is facilitated by CO2 decomposition.
• CO photoreduction can lead to CH4, while CH3OH formation is hindered by strong adsorption and decomposition.

Conclusions:

• CaTiO3 shows potential for CO2 photoreduction, primarily yielding CO and CH4.
• Energy barriers and intermediate stability dictate product selectivity.
• Further catalyst design is needed to enhance HCOOH and CH3OH production.