Hydrothermal-Freeze-Casting of Poly(amidoamine)-Modified Graphene Aerogels towards CO2 Adsorption

This article presents novel poly(amidoamine) (PAMAM) dendrimer-modified with partially-reduced graphene oxide (rGO) aerogels, obtained using the combined solvothermal synthesis-freeze-casting approach. The properties of modified aerogels are investigated with varying synthesis conditions, such as dendrimer generation (G), GO:PAMAM wt. ratio, solvothermal temperature, and freeze-casting rate. Scanning electron microscopy, Fourier Transform Infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy are employed to characterize the aerogels. The results indicate a strong correlation of the synthesis conditions with N content, N/C ratio, and nitrogen contributions in the modified aerogels. Our results show that the best CO2 adsorption performance was exhibited by the aerogels modified with higher generation (G7) dendrimer at low GO:PAMAM ratio as 2:0.1 mg mL(-1) and obtained at higher solvothermal temperature and freeze-casting in liquid nitrogen. The enclosed results are indicative of a viable approach to modify graphene aerogels towards improving the CO2 capture.

Automated summary

This study introduces a novel approach to modify graphene aerogels by using a combined solvothermal synthesis-freeze-casting method to obtain PAMAM dendrimer-modified rGO aerogels. The properties of the aerogels are found to be strongly correlated with the synthesis conditions, with the best CO2 adsorption performance exhibited by aerogels modified with higher generation dendrimers under specific conditions.