High-performance non-enzymatic hydrogen peroxide electrochemical sensor prepared with a magnetite-loaded carbon nanotube waterborne ink

Abstract

In this study, a non-enzymatic hydrogen peroxide sensor was developed employing a waterborne carbon nanotube ink containing catalytic submicrometric particles of magnetite. Magnetite particles were synthesized via a solvothermal method and characterized by scanning electron microscopy (SEM) and powder X-ray diffraction measurements (XRD). For the ink preparation, Fe3O4 particles were incorporated into a waterborne carbon nanotube ink and the mixture was drop casted onto a glassy carbon and used for coating ValoxTM strips to fabricate standalone electrodes. As a non-enzymatic amperometric sensor, the resulting Fe3O4/CNT ink coated electrodes exhibited high-performance values towards the detection of H2O2, presenting a limit of detection of 0.5 µM, a linear detection range up to 2 mM, a sensitivity of 1040 µA cm−2 mM−1 and tolerance to common interfering agents like ascorbic acid, glucose and Cl-/SO4-2 ions. Moreover, the Fe3O4/CNT electrodes presented a high stability, losing only 20% of their catalytic performance after three weeks.