Fe-doped two-dimensional graphite carbon nitride: An effective nanozymetic catalyst for electrochemical detection of cell-released H2O2

Abstract

In this work, a simple one-step pyrolysis process was designed to synthesize Fe-doped graphite carbon nitride (Fe–C3N4) nanosheets with FeCl3 as Fe source. The resulted samples were characterized by various characterization techniques, and the results showed that Fe species might form Fe–N bonds with N atoms of C3N4, which was similar to the iron (II) porphyrin active center of horseradish peroxidase. Then Fe–C3N4 nanosheet was further mixed with carbon nanotube (CNT) to obtain Fe–C3N4@CNT nanocomposite, which was further modified on the self-made flexible printed electrode (PE) to construct the flexible working electrode. Fe–C3N4 nanosheets show good catalytic activity for H2O2 and the introduction of CNT can effectively improve the electron transfer efficiency at the modified electrode interface. By combining with wireless portable electrochemical workstation, the sensor shows a wider detection range (10.0 μmol L−1–20.0 mmol L−1) and a lower limit of detection (0.38 μmol L−1, S/N = 3) for the H2O2 analysis. Furthermore, the sensor can be applied to the real time and in-situ analysis of H2O2 secreted from live cells. In word, this self-supported sensing electrode shows great potential applications in monitoring the pathological and physiological dynamics of cancer cells.