Superior Performance of Copper Based MOF and Aminated Graphite Oxide Composites as CO₂ Adsorbents at Room Temperature

New composites Cu-BTC MOF and graphite oxide modified with urea (GO-U) are developed and tested as CO₂ adsorbents at room temperature. The composite containing GO-U with the highest nitrogen content exhibits an excellent CO₂ uptake (4.23 mmol/g) at dynamic conditions. The incorporation of GO-U into MOF changes the chemistry and microstructure of the parent MOF and results in synergistic features beneficial for CO₂ retention on the surface. To identify these features the initial and exhausted materials were extensively characterized from the points of view of their porosity and chemistry. Although the adsorption forces are relatively strong, the results indicate that CO₂ is mainly physisorbed on the composites at dry dynamic conditions at ambient temperature and pressure. The primary adsorption sites include small micropores specific for the composites, open Cu sites, and cage window sites.