[en] Full text: Since the industrial revolution, the consume of fossil fuels led to an exponential increase of CO₂ and CH₄ emission into the atmosphere. In this context, the development of materials that are capable of capturing and storing CO₂ becomes essential. The absorption in porous solids requires materials with high surface area, high selectivity, thermal resistance, and moisture tolerance. Carbon nitrides as adsorbents present promising results due to their high chemical and physical stabilities along with their inexpensive and sustainable preparation methods. Furthermore, the acid-base interactions with CO₂, an acid molecule, are intensified with the presence of terminal amines on the defects in the graphitic carbon nitride (GCN) nanosheets. In this work, we present the syntheses of pure graphitic carbon nitrides, using different precursors and the application as a potential CO₂ adsorbent. Through a thermal polymerization method, the GCN were synthesized from melamine (MGCN), dicyandiamide (DGCN) and urea (UGCN). GCNs were characterized by X-ray diffraction, and showed two characteristics peaks at 2θ=27.3° (002) and 2θ=13.7° (100) associated with the distance and space between the graphitic materials sheets, respectively. TGA showed two predominant weight loss events, one at 150 ºC related to desorption of H2O molecules and the second one in the range of 560-600ºC, confirming the chemical stability of the basic units of heptazine. CO₂ adsorption studies were carried out at high and low pressures at 30 °C, and UGCN exhibited the best result among the three materials, 2.5 mmol/g CO₂ at 20 bar. The syntheses are being optimized to improve the adsorption capacities of this material. (author)