Comprehensive study on graphene hydrogels and aerogels synthesis and their ability of gold nanoparticles adsorption

Abstract Graphene hydrogels were prepared by ascorbic acid-assisted gelation of graphene oxide (GO) aqueous suspensions both in acidic and basic conditions. Different mass ratio of ascorbic acid (AA) to GO was used (namely 20:1 and 10:1). In order to eliminate the influence of AA on the final structure of hydrogels, samples without AA were prepared by a hydrothermal gelation of GO in an autoclave. An in-depth structural characterization of the obtained materials was performed before and after supercritical drying by means of FTIR, XRD and SEM. Surface area of hydrogels was determined using the methylene blue adsorption method. BET surface area and pore volume analysis of aerogels was also performed. The effect of initial GO concentration and volume on the final graphene aerogels structure was determined. Electrochemical properties of samples were also evaluated. Finally, gold nanoparticles (Au NP) adsorption on graphene hydro- and aerogels was presented for the first time. Graphene hydrogels and aerogels are promising candidates for practical applications e.g. in the Au NP removal from wastewater.