Robust and conductive mesoporous reduced graphene oxide-silica hybrids achieved by printing and the sol gel route

Abstract

Reduced graphene oxide (rGO) scaffoldings are used as templates to create lightweight 3D rGO/silica and rGO/silico-aluminate hybrids by a simple impregnation route and the sol-gel method. The printed rGO assemblies are infiltrated by the corresponding alkoxide precursor solution and gelled by exposure to ammonia vapours, producing an hybrid replica of the rGO structure. The hybrids show a significant prevalence of mesopores, with total porosity above 94 %, density of ∼ 0.1 g⋅cm−3 and high specific surface area (≥ 190 m2⋅g−1). As a result, the 3D composite materials show enhanced water adsorption capacity and hydrophilicity, display compressive strengths in the range 0.1 – 0.4 MPa, which scale with the proportion of silica (or Al-modified silica) on the hybrid scaffold, and electrical conductivities are above 60 S⋅m−1. These properties are very attractive for applications in the removal of pollutants, water filtering, catalysis, drug delivery, or energy production and storage.