A novel 1D/2D Bi2S3/g-C3N4 core–shell nanocomposite as a highly performing H2O2 non-enzymatic electrochemical sensor

We report the synthesis of a new non-enzymatic H2O2 electrochemical sensor based on the Bi2S3/g-C3N4 core–shell nanocomposite. The Bi2S3/g-C3N4 nanocomposite was synthesized via the solvothermal process. It was characterized by XRD and TEM to identify its phase and to determine its morphology. The response of Bi2S3/g-C3N4 nanocomposite to hydrogen peroxide was investigated using the cyclic voltammetry and amperometry techniques. The obtained results show that the association of g-C3N4 nanosheets with Bi2S3 nanorods enhances the electrochemical behavior and the overall performance of the sensor. Indeed, we noted an enhanced electrochemical signal of the Bi2S3/g-C3N4 core–shell nanocomposite shown by the appearance of a H2O2 oxidation peak at around 0.26 V. Moreover, the modified Bi2S3/g-C3N4 electrode sensor demonstrated a wide linear range for H2O2 from 0.5 to 950 μM with a sensitivity of 1011 μA mM−1cm−2 and a detection limit of 78 nM. These performances are much better than those for Bi2S3 and g-C3N4 taken separately. The improved electrocatalytic activity of the sensor towards hydrogen peroxide oxidation is mainly attributed to the morphology of the core–shell nanostructure leading to the enrichment of electroactive sites for the catalytic reaction of H2O2. Additionally, the proposed sensor was successfully tested in skimmed milk and human urine samples. The novelty of this work is the simple way to synthesis Bi2S3/g-C3N4 core–shell nanostructure and its use as a H2O2 sensor, which paves the way for the synthesis of new nanomaterial heterostructures used as electrochemical sensors for detecting other molecules.