S-doped reduced graphene oxide: a novel peroxidase mimetic and its application in sensitive detection of hydrogen peroxide and glucose.

This article presents a novel peroxidase mimetic by doping S atoms into reduced graphene oxide (rGO), which was synthesized through a facile hydrothermal reaction without any templates or surfactants. The peroxidase-like activity of S-doped rGO (S-rGO) is greatly boosted compared with the pristine rGO, demonstrating the peroxidase-like active sites are dominantly originated in sulfur-containing groups. The steady-state kinetic studies further indicate that S-rGO obeys the typical Michaelis-Menten curves and has a much smaller Michaelis constant (Km) for hydrogen peroxide (H2O2) and 3, 3', 5, 5'-tetramethylbenzidine (TMB). In view of the outstanding performance of S-rGO as a peroxidase mimetic, an efficient and sensitive colorimetric detection platform for H2O2 and glucose has been successfully established. The linear detection for H2O2 is obtained in a range of 0.1-1 μM with an extremely lower detection limit of 0.042 μM, and glucose can be measured in a linear range of 1-100 μM, giving a detection limit of 0.38 μM. This study not only provides a new avenue for the reasonable design of heteroatom-doped carbon-based nanomaterials but also offers meaningful reference for detecting the important biomolecules in biotechnology. Graphical abstract.