Evaluation of Nitrogen-Doped Adsorbents Based on Reduced Graphene Oxide as Platforms for CO₂ Capture

CO₂ emissions into the atmosphere have been rapidly rising due to human activities, resulting in the escalation of global warming. To mitigate climate change, it is imperative to develop materials for CO₂ capture with high CO₂ capacity and low production costs. Herein, we developed a facile method to obtain adsorbents based on reduced graphene oxide (rGO) sheets, NrGO(1 – X)700, where X represents the mass of diethylenetriamine (DETA) (X = 1, 2 and 4 g) used in the preparation. The materials NrGO(1 – 1)700, NrGO (1 – 2)700, and NrGO(1 – 4)700 were obtained from graphene oxide dispersions, followed by DETA impregnation and chemical activation with K₂CO₃. N₂ isotherms demonstrated that the materials simultaneously presented micro and mesopores with similar values of specific surface area (280.16 to 310.32 m² g^–1), pore volume (0.26 to 0.28 cm³ g^–1) and pore size (3.78 to 3.80 nm). CO₂ sorption experiments revealed that the material NrGO(1 – 4)700, containing the highest amount of pyridinic, graphitic, and amino nitrogen functionalities, showed the best CO₂ adsorption capacity. Diffuse reflectance Fourier transformed infrared spectroscopy experiments indicated stronger solid-gas interactions for NrGO(1 – 4)700 than for the other materials.

Keywords:
CO₂ capture; porous materials; reduced graphene oxide; nitrogen-doped adsorbent