Synthesis and characterization of ammonia strengthened and ambient dried N-doped hydrophilic graphene aerogel with good electrical conductivity

Abstract

We present a novel ‘one-pot’ approach for strengthening reduced graphene oxide (rGO) hydrogels by nitrogen doping. Ammonia is directly added to the precursor reaction mixture prior to hydrothermal gel formation, as opposed to treating as-synthesised rGO hydrogel by ammonia in a second hydrothermal process. This process ensures that the resulting hydrogels are sufficiently robust that aerogels may then be produced by natural drying under ambient temperture and pressure. The as-formed rGO aerogel possesses a Young's modulus as high as 28 kPa and exhibits superelasticity, withstanding strains of up to 95 %. Moreover, the strengthed graphene aerogel possesses an electrical conductivity of up to 1.5 S cm⁻¹ and a specific surface area of 280.0 m² g⁻¹. Although the rGO aerogel was sufficiently reduced to provide good electrical conductivity, it retains a water contact angle of 47 ± 1°, indicating hydrophilic behaviour.