Graphene micro-aerogel based voltammetric sensing of p-acetamidophenol

Abstract

The authors describe a method for the fabrication of graphene micro-aerogels (GMA) using a multiple emulsion as a soft template. A mixed surfactant consisting of polymannitol oleate ester and polyoxyethylene castor oil was dissolved in toluene. An aqueous dispersion of graphene oxide was dropped into the above solution to produce a water-in-oil-in-water multiple emulsion. Hydrazine was used to reduce the graphene oxide. The partly reduced sheets of graphene oxide diffuse into the oil phase due to their low polarity. This induces the self-assembly of graphene sheets at the oil-water interface to finally form GMA. Following freeze drying and thermal annealing at 900 °C under Ar/H2, GMA is obtained which possesses a microcapsule-like structure, high electrical conductivity (3250 S m−1), a large specific surface (1253 m2 g−1) and a well-defined porous structure. A glassy carbon electrode modified with the GMA shows ultrahigh sensitivity for the electrochemical detection of p-acetamidophenol. The differential pulse voltammetric peak current increases linearly over the 1 × 10−8 to 8.0 × 10−5 M p-acetamidophenol concentration range, and the detection limit is 5.7 × 10−9 M (at an S/N ratio of 3). The sensitivity is much better than that of sensors based on the use of graphene, graphene aerogel, or high density graphene aerogel. The method was successfully applied to the determination of p-acetamidophenol in tablets. The study also provides promising prospects in terms of graphene aerogel materials with improved electrochemical performance in electrocatalysis, supercapacitors and lithium ion batteries.