Trends in Carbon Dioxide Capture and Conversion

Carbon dioxide capture and conversion is gaining increased attention due to climate change issues. The direct air capture of CO₂ may be accomplished with functionalized adsorbents that can work at atmospheric pressure and room temperature. The captured CO₂ may be converted into fuels and chemicals. CO₂ can be hydrogenated to methanol, which is a commodity used in the fuel and chemical sectors, over Cu.ZnO-based catalysts. Improvements to catalyst formulation are still needed to operate at lower temperatures. Dimethyl ether can be directly produced from CO₂ and H₂ through the use of bifunctional catalysts. Organic carbonates appear as promising compounds of wide use in the chemical sector. Cyclic carbonates may be produced from CO₂ and epoxides with the use of Lewis acids catalyst. Zeolites impregnated with metal halides appear to be a promising system to achieve high conversion and selectivity. Aliphatic organic carbonates can be produced from CO₂ and alcohols, but the reaction presents thermodynamic limitations. The role of oxygen vacancies on CeO₂-based catalysts and use of dehydrating agents in the production of dimethyl carbonate will be discussed in this account. The challenges and future perspectives for the direct air CO₂ capture and conversion into fuels and chemicals will be addressed.

Keywords:
CO₂; CCU; methanol; DME; organic carbonates; chitosan