Unidirectionally porous RGO aerogels as electrocatalyst support

2 figures.-- Abstract of the poster presented at the IX Carbocat 2022, 28th-30th June, Zaragoza, Spain.Interest in 3D-graphene structures is increasing as a way to translate the characteristics of individual graphene sheets onto the macroscale. Among them, graphene aerogels offer useful properties such as high specific surface area, open porous network allowing ion transport, flexibility, tough mechanical strength while constituting conductive framework structures.[1] Gelation of graphene oxide (GO) dispersions is the most common way to obtain graphene aerogels.[2] For this, GO dispersions are subjected to an hydrothermal treatment in an autoclave that leads to the removal of oxygenated functional groups. This reduction directly increases the hydrophobicity and reduces the amount of surface charges, producing the crosslinking of the reduced GO (RGO) sheets. Therefore, phase separation takes place inducing the hydrogel formation. Eventually, a further freeze-drying step allows to obtain the desired RGO aerogels. In this work, different conditions of the hydrothermal process such as time or pH have been studied. pH has been found to be key in the reduction degree and morphology of the final RGO hydrogel and subsequent transformation into an aerogel. Varying from acidic pH to basic pH, which is attained by the addition of ammonia during the hydrogel formation, an increase of the porosity, is observed.Spanish MICINN/AEI: PID2019- 104272RB-C51/AEI/10.13039/501100011033; Government of Aragón: Grupos Reconocidos DGA T03_20R and PhD grant of CC IIU/796/2019