Increasing the efficiency of reduced graphene oxide obtained via high temperature electrospun calcination process for the electrochemical detection of dopamine

Abstract

• XRD confirms the crystalline nature of reduced graphene oxide by using thermal annealing at 500 °C and 600 °C. • XPS analysis confirmed the successful removal of oxygenated groups from the surface of polymeric membrane at higher temperature. • The removal of excess oxygenated groups such as epoxy, carboxyl and hydroxyl resulted in the improved conduction of graphite structure in rGO. • Application of the developed material for the electrochemical detection of dopamine after modification of screen printed carbon electrode. Reduced graphene oxide (rGO) has attracted significant attention for electrochemical sensing applications. In this work, rGO was obtained by thermal annealing of electrospun polymeric nanofiber membrane at 500 and 600 °C. The XRD patterns reveals the phase and crystalline formation of rGO. The interlayer spacing decreases at higher temperature that indicates the removal of oxygen containing moieties. FTIR spectrum shows the absence of epoxy, carboxyland hydroxylgroups for rGO-600 that resembles the surface feature of rGO. XPS further corroborates the XRD and FTIR results and quantifies the predominant functional groups in rGO-500 and rGO-600 °C. The synthesized materials were applied for the electrochemical sensing of dopamine (DA) by cyclic voltammetry. In the case of rGO-500/SPCE, a linear relationship for the DA concentration wasobserved in the range of 0.5 µM to 20 µM with a detection limit of 1.11 µM. Whereas, rGO-600/SPCEalso gave a linear relationship for the DA concentration in the range of 0.5 µM to 20 µM with 1.23 µM detection limit. These electrodes showed good electrocatalytic activity for the oxidation of DA with a minute variation in their detection limit. Therefore, the annealed material rGO can be efficiently used for the quantitative analysis of dopamine after carefully controlling the surface functional groups.