Enhanced CO₂ Capture of Poly(amidoamine)-Modified Graphene Oxide Aerogels with the Addition of Carbon Nanotubes

Innovative dendrimer-modified graphene oxide (GO) aerogels are reported by employing generation 3.0 poly(amidoamine) (PAMAM) dendrimer and a combined synthesis approach based on the hydrothermal method and freeze-casting followed by lyophilization. The properties of modified aerogels were investigated with the dendrimer concentration and the addition of carbon nanotubes (CNTs) in varying ratios. Aerogel properties were evaluated via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The obtained results indicated a strong correlation of the N content with the PAMAM/CNT ratio, where optimum values were revealed. The CO₂ adsorption performance on the modified aerogels increased with the concentration of the dendrimer at an appropriate PAMAM/CNT ratio, reaching the value of 2.23 mmol g^-1 at PAMAM/CNT ratio of 0.6/0.12 (mg mL^-1). The reported results confirm that CNTs could be exploited to improve the functionalization/reduction degree in PAMAM-modified GO aerogels for CO₂ capture.