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.