Modeling of activated carbon and multi-scale molecular simulation of its water vapor adsorption: A review

The combination of water vapor, which is ubiquitous, and activated carbons (ACs), the most common adsorbent, is widely used in several fields, including energy storage, dehumidification, and gas separation, among others. Exploring the water vapor adsorption mechanism of ACs at the microscopic level is essential for optimizing material design and improving adsorption performance. So far, a large number of simulation studies based on the Grand Canonical Monte Carlo (GCMC) method have preliminarily grasped the adsorption mechanism of water vapor on ACs. In recent years, molecular dynamics (MD) and density functional theory (DFT) simulations have provided new insights into the dynamic behavior of water molecules and the carbon-water interaction at the electronic scale. However, any single technique can merely offer a one-sided perspective and partial comprehension, while the absence of multi-scale simulations hinders the attainment of a comprehensive and profound understanding of the structure-function relationship between water vapor adsorption and ACs. On the other hand, the model and the force field, which determine the accuracy of the simulation, lack a review of their selection principles. Therefore, this paper reviews the current application status of common AC models and their progress in multi-scale simulation studies of GCMC, MD and DFT for adsorbed water vapor. On the one hand, the complete system of model-force field-simulation is reviewed. On the other hand, the multi-scale adsorption mechanism of water vapor on ACs is revealed, which is essential for advancing future simulation work in this field.