CO₂ Hydrogenation on Ru Single-Atom Catalyst Encapsulated in Silicalite: a DFT and Microkinetic Modeling Study

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Rising CO2 emissions necessitate innovative capture and conversion strategies.
• Porous materials like zeolites and MOFs are key for CO2 capture.
• Converting captured CO2 into valuable fuels supports a circular economy.

Purpose of the Study:

• To investigate the catalytic CO2 hydrogenation mechanism over Ru single-atom catalysts (SACs) encapsulated in silicate (Ru1@S-1).
• To elucidate the reaction pathways, rate-determining steps, and product selectivity using computational methods.

Main Methods:

• Proposed a detailed mechanism with 47 elementary reactions.
• Employed periodic density functional theory (DFT) calculations.
• Utilized microkinetic modeling simulations under varying temperatures and pressures.

Main Results:

• Carbon monoxide (CO) is the primary gas product, followed by formic acid and formaldehyde.
• CO formation predominantly occurs via direct CO2 dissociation (redox mechanism).
• Desorption of CO and formaldehyde are the rate-limiting steps for their respective formations.

Conclusions:

• Ru1 SACs exhibit high selectivity towards CO production.
• The findings align with experimental and theoretical studies on Ru SACs for CO2 conversion.
• Understanding these mechanisms is crucial for designing efficient catalysts for CO2 utilization.