Water-Gas Shift Reaction to Capture Carbon Dioxide and Separate Hydrogen on Single-Walled Carbon Nanotubes

In view of the increasingly severe global warming and ocean acidification caused by CO2 emissions, we report a new procedure, named "reactive separation", to capture CO2. We used advanced Monte Carlo and molecular dynamics methods to simulate the water-gas shift reaction in single-walled carbon nanotubes. We found that (11,11) carbon nanotubes with a diameter of 0.75 nm have the best ability to capture CO2 generated in the water-gas shift reaction. When the feed water-gas ratio is 1:1, the pressure is 3 MPa, and the temperature is 473 K, the storage capacity of CO2 reaches 2.18 mmol/g, the molar fraction of CO2 and H-2 inside the carbon nanotube is 0.87 and 0.09, respectively, the conversion of CO in the pore is as high as 97.6%, and the CO2/H-2 separation factor is 10.3. Therefore, utilizing the reaction and separation coupling effect of carbon nanotubes to adsorb and store the product CO2 formed in the water-gas shift reaction, while separating the generated clean energy gas H-2, is a promising strategy for developing novel CO2 capture technologies.