Synthesizing High-Volume Chemicals from CO₂ without Direct H₂ Input.

Area of Science:

• Chemical Engineering
• Green Chemistry
• Catalysis

Background:

• Decarbonizing the chemical industry necessitates utilizing carbon dioxide (CO2) as a chemical feedstock.
• Current CO2 utilization often involves reduction via renewable hydrogen, which is energy-intensive.

Purpose of the Study:

• To review chemical processes that employ CO2 as an oxidant for hydrocarbon upgrading.
• To explore hydrogen-free CO2 utilization pathways for synthesizing valuable chemicals.

Main Methods:

• Discussion of catalytic systems and reactor designs for CO2 oxidation of hydrocarbons.
• Analysis of overcoming thermodynamic limitations, over-oxidation, coking, and heat management challenges.

Main Results:

• Identified potential synthesis of eight emission-intensive molecules, including olefins and epoxides, using CO2 as an oxidant.
• Demonstrated that hydrocarbons can inherently reduce CO2 in these reactions, eliminating the need for external reducing agents like H2.

Conclusions:

• Hydrogen-free CO2 utilization as an oxidant presents a viable strategy for decarbonizing the chemical industry.
• These processes show a potential CO2 abatement of ~1 gigaton/year and avoid consuming 1.24 PWh of renewable electricity.