To reveal the mechanism of energy storage in the water/graphene system and water/grapheme-oxide system, the processes of rapid evaporation of water molecules on the sheets of graphene and graphene-oxide are investigated by molecular dynamics simulations. The results show that both the water/graphene and water/grapheme-oxide systems can store more energy than the pure water system during evaporation. The hydroxyl groups on the surface of graphene-oxide are able to reduce the attractive interactions between water molecules and the sheet of graphene-oxide. Also, the radial distribution function of the oxygen atom indicates that the hydroxyl groups affect the arrangement of water molecules at the water/graphene-oxide interface. Therefore, the capacity of thermal energy storage of the water/graphene-oxide system is lower than that of the water/graphene system, because of less desorption energy at the water/graphene-oxide interface. Also, the evaporation rate of water molecules on the graphene-oxide sheet is slower than that on the graphene sheet. The Leidenfrost phenomenon can be observed during the evaporation process in the water/grapheme-oxide system.

Incomplete hydration shells facilitate the hydrolysis of CO₃²⁻to be not only thermodynamically favorable but also kinetically favorable.

In the quest to mitigate carbon dioxide emissions, it becomes essential to address the existing atmospheric CO₂. Effective and economical methodologies, particularly those without additional energy consumption, are crucial. Currently, a leading method is the direct capture of CO₂ using ion exchange resins, which achieve the adsorption and desorption of carbon dioxide simply by using the humidity variations. This technology, though minimizing additional energy cost, still needs improvement in its efficiency in CO₂ capture capacity and compared to other methods. In this work, we develop low-cost techniques to reduce the AmberLite™ IRA900 Cl (IRA-900) anion exchange resin to micro size, and observe significant performance enhancement on CO₂ capture efficiency contingent on reducing the particle diameters. This performance disparity is attributed to the differential water adsorption capacities inherent in particles of diverse diameters. Our results reveal that smaller resin particles outperform their larger counterparts, exhibiting accelerated adsorption rates and expedited transitions from wet to dry states. Notably, these smaller particles display a quintupled enhancement in adsorption efficacy relative to non-treated particles and a marked increase in relative adsorption capacity. Upon treatment, IRA-900 demonstrates robust CO₂ processing efficiency, achieving a peak adsorption rate of 1.28 g/mol·h and a maximum desorption rate of 1.18 g/mol·h. Also, the material is subjected to almost 100 cycles of testing, and even after 100 cycles, the resin particles maintain a capacity of 100%. Moreover, our material can be fully regenerated to 100% efficiency by simply immersing it in water. Simultaneously, storing it in water allows for the long-term maintenance of its performance without other treatment methods. A key observation is the resin’s sustained performance stability post extended exposure to humid conditions. These outcomes offer substantial practical implications, emphasizing the relevance of our study in practical environmental applications.

A new phosphorous allotrope, closed-edged bilayer phosphorene nanoribbon, is proposed via radially deforming armchair phosphorene nanotubes. Using molecular dynamics simulations, the transformation pathway from round PNTs falls into two types of collapsed structures: arc-like and sigmoidal bilayer nanoribbons, dependent on the number of phosphorene unit cells. The fabricated nanoribbions are energetically more stable than their parent nanotubes. It is also found via ab initio calculations that the band structure along tube axis substantially changes with the structural transformation. The direct-to-indirect transition of band gap is highlighted when collapsing into the arc-like nanoribbons but not the sigmoidal ones. Furthermore, the band gaps of these two types of nanoribbons show significant size-dependence of the nanoribbon width, indicative of wider tunability of their electrical properties.