CO₂ Hydrogenation to Methanol over Cd₄/TiO₂ Catalyst: Insight into Multifunctional Interface.

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Supported metal catalysts are effective for CO2 conversion due to stability and multifunctionality.
• Understanding catalytic mechanisms is crucial for optimizing CO2 hydrogenation to methanol.
• The Cd4/TiO2 catalyst presents a novel system for CO2 reduction.

Purpose of the Study:

• To investigate the catalytic reaction mechanisms of CO2 hydrogenation to methanol over Cd4/TiO2.
• To identify the active sites and dominant reaction pathways for methanol synthesis.
• To determine the rate-determining step in the CO2 to CH3OH conversion process.

Main Methods:

• Density functional theory (DFT) calculations were employed to explore reaction energetics and intermediates.
• Microkinetic modeling was utilized to simulate the catalytic process and identify rate-limiting steps.
• The study focused on the Cd4/TiO2 catalyst system.

Main Results:

• The metal-oxide interface of Cd4/TiO2 acts as the active center for CO2 hydrogenation.
• Methanol formation predominantly occurs via the formate pathway, outcompeting the reverse water-gas shift (RWGS) pathway.
• Formate species on the Cd4/TiO2 surface are key intermediates, and CH2O formation is the rate-determining step.

Conclusions:

• The Cd-TiO2 interface plays a critical role in controlling CO2 reduction reactivity and methanol selectivity.
• The formate pathway is the preferred route for methanol synthesis over this catalyst.
• Identifying the rate-determining step provides insights for catalyst design and process optimization.