Using grand canonical Monte Carlo simulations, computational screening of hundreds of pure silica zeolites were conducted to identify materials that show enhanced CO2 uptake under humid conditions. Herein, we show that CO2 adsorption performance can be either enhanced or degraded depending on the CO2/H2O binding site separations and characteristics of CO2-H2O interaction energies. As expected, CO2 adsorption capacity is significantly degraded when its binding sites overlap with the H2O sites. On the other hand, CO2 adsorption performance is enhanced when CO2/H2O binding sites are clearly separated as shown from the molecular simulations. However, we show that there are zeolite structures where CO2 enhancement is observed despite the close distance between the CO2 and H2O binding sites. It is demonstrated that favorable long-range Coulomb interaction between CO2 and H2O molecules is responsible for enhanced CO2 adsorption performance in these materials.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the financial support from the Saudi Aramco-KAIST CO2 Management Center. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility Supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
© 2016 American Chemical Society.