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

Abstract

• Magnetite-loaded carbon nanotube waterborne ink with peroxidase-like activity. • Mechanical stability allowing determinations in forced convection/quiescent conditions. • Ease of preparation, suitable for inkjet and screen-printing methods. • Remarkable analytical figures of merit towards the detection of hydrogen peroxide. • Composite’s formulation optimized to maximize its catalytic properties. 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, Fe 3 O 4 particles were incorporated into a waterborne carbon nanotube ink and the mixture was drop casted onto a glassy carbon and used for coating Valox TM strips to fabricate standalone electrodes. As a non-enzymatic amperometric sensor, the resulting Fe 3 O 4 /CNT ink coated electrodes exhibited high-performance values towards the detection of H 2 O 2 , 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 Fe 3 O 4 /CNT electrodes presented a high stability, losing only 20% of their catalytic performance after three weeks.