One-step in situ hydrothermal preparation of graphene–SnO<inf>2</inf> nanohybrid for superior dopamine detection

Abstract: In this work, we report a facile and one -step hydrothermal method to decorate SnO2 nanostructures on few-layered graphene for superior dopamine detection. The structural and morphological properties of the prepared nanohybrids illustrated the tetragonal crystal system of SnO2, reconstruction of graphene layers with oxygen containing functional groups, increased ID/IG ratio, and uniform decoration of SnO2 nanostructures on graphene layers. The prepared nanohybrids exhibited a high electrochemical activity toward dopamine oxidation in comparison with individual graphene sheets. This enhanced performance can be due to the presence of SnO2 nanostructures between the graphene layers, which efficiently avoid the restacking and increase the surface area accessibility. The fabricated nanohybrid-based sensor showed an increase in current with respect to the increased analyte concentration over the wide range of 0.005–0.20 × 10−6 M. The sensor exhibits excellent catalytic activity toward dopamine with the lowest detection limit of 6.3 nm. Further, the modified electrode exhibited good stability, reproducibility, and better recovery of 99 % in human urine samples suggesting the real-time usability of the sensor. Graphical Abstract: Schematic representation of SnO2 nanohybrids formation. The modified electrode exhibits superior catalytic activity. The oxidation peak current increased linearly in the concentration range of 0.005–0.019 × 10−6 M with LOD of 6.3 nm.[Figure not available: see fulltext.]