Amperometric Non-Enzymatic Hydrogen Peroxide Sensor Based on Aligned Zinc Oxide Nanorods

Abstract

Zinc oxide (ZnO) nanorods (NRs) have been synthesized via the hydrothermal process. The NRs were grown over a conductive glass substrate. A non-enzymatic electrochemical sensor for hydrogen peroxide (H₂O₂), based on the prepared ZnO NRs, was examined through the use of current-voltage measurements. The measured currents, as a function of H₂O₂ concentrations ranging from 10 μM to 700 μM, revealed two distinct behaviours and good performance, with a lower detection limit (LOD) of 42 μM for the low range of H₂O₂ concentrations (first region), and a LOD of 143.5 μM for the higher range of H₂O₂ concentrations (second region). The prepared ZnO NRs show excellent electrocatalytic activity. This enables a measurable and stable output current. The results were correlated with the oxidation process of the H₂O₂ and revealed a good performance for the ZnO NR non-enzymatic H₂O₂ sensor.

Keywords: hydrogen peroxide; nanorods; non-enzymatic biosensor; zinc oxide.

Figure 1

The XRD pattern of the prepared ZnO NRs on the AZO substrate.

Figure 2

I-V characteristics of the ZnO NR sensing electrode for H₂O₂ in concentrations ranging from 10 μM to 700 μM.

Figure 3

Response of the AZO/ZnO NR sensing electrode at bias voltages of 5 V in a diluted solution of H₂O₂ in concentrations ranging from 10 μM to 700 μM.

Figure 4

The amperometric response of the ZnO NR/AZO electrode upon successive additions of H₂O₂. The bias voltage was fixed at 5 V.