A simple preparation of N-doped reduced graphene oxide as an electrode material for the detection of hydrogen peroxide and glucose

Abstract

This paper presents a method of simple and facile preparation of N-doped reduced graphene oxide (N-rGO), which can be applied as a metal-free electroactive electrode material for the detection of hydrogen peroxide and glucose. Two different N-rGO samples (N-rGO_850 and N-rGO_950) were obtained by gaseous NH3-assisted thermal modification of reduced graphene oxide (rGO) at temperatures of 850 °C and 950 °C for 4 and 8 h, respectively. The structural properties of the samples obtained were characterized by Raman spectroscopy, XPS, and N2 adsorption-desorption techniques. Taken together, these analyses demonstrate that, compared to the N-rGO_850 sample, N-rGO_950 possesses a considerably higher amount of quaternary nitrogen species, higher surface area, and a greater amount of structural imperfections, which contribute to its excellent electrochemical activity in the detection of H2O2 and glucose. The sensor based on N-rGO_950 displays a fast response time (∼ 6 s) to sensitive detection of H2O2, a wide linear range (0.1 – 10.7 mM), a sufficiently low limit of detection (LOD) of 26.0 μM, and a superior sensitivity (305 μA mM−1 cm−2). When the same sensor platform used in glucose detection after GOx immobilization results in LOD of 24.7 μM with a linear range of 0.01 – 3.38 mM and a sensitivity of 60.2 μA mM−1 cm−2. Moreover, the proposed (bio)sensor demonstrates satisfactory selectivity, reproducibility, repeatability, and stability.