Pressurized synthesis of composite carbon foams based on calcium salts

This study proposes an innovative and ecological approach for the synthesis of carbon-contained composite foams from glucose through thermal decomposition under pressure. Calcium chloride reaction through foam treatment in CO₂- NH₃-H₂O vapors provides additional functions of the material. CaCl₂ conversion enables advanced gas absorption applications. These findings clearly demonstrate the material’s capacity for effective absorption of both water vapor and volatile acids concurrently allowing their use as phase transformation materials (PCMs). The porous and hydrophilic nature of the carbon foam increases the contact surface of the concentrated CaCl₂ solution-wet air interface, increasing the absorption speed of water vapors and simultaneously preventing the leakage of the formed liquid. The compression testing shows that the mechanical strength of the foam is influenced by the glucose – CaCl₂ ratio. The X-ray diffraction and Fourier Transform Infrared analyses confirmed the compositional changes in the foam after CO₂ treatment. According to X-ray diffraction analysis, the formation of calcite as a single crystalline phase, can be clearly observed. After prolonged heating of the foams initially treated in CO₂ and NH₃ vapors, no traces of NH₄Cl are detected, indicating its complete sublimation during the thermal treatment. The results obtained show that the carbon foams synthesized by this method have multiple uses, including different gas capture and thermal management. This work was supported by a grant of the Ministry of Research, Innovation, and Digitization, CCCDI-UEFISCDI, project number PN-IV-P8-8.3-PM-RO-BE-2024-0004 within PNCDI IV.