Development of a hydrogen peroxide sensor based on palladium and copper electroplated laser induced graphene electrode

In this paper, we describe the fabrication and characterization of a hydrogen peroxide (H₂O₂) sensor based on palladium and copper (PdCu) electroplated laser induced graphene (LIG) electrodes. CO₂ laser was used to form LIG electrodes on a PI film. This fabrication method allows simple control of the LIG electrode size and shape. The PdCu was electrochemically deposited on the LIG electrodes to improve the electrocatalytic reaction with H2O2. The electrochemical performance of this sensor was evaluated in terms of selectivity, sensitivity, and linearity. The physical characterization of this sensor was conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), which confirmed that PdCu was formed on the laser induced graphene electrode. In order to increase the sensor sensitivity, the Pd:Cu ratio of the electroplated PdCu was varied to five different values and the condition of highest amperometric current at an identical of H2O2 concentration was chosen among them. The resulting amperometric current was highest when the ratio of Pd:Cu was 7:3 and this Pd;Cu ratio was employed in the sensor fabrication. The fabricated PdCu/LIG electrode based H2O2 sensor exhibited a sensitivity of 139.4 μA/mM·cm², a broad linear range between 0 mM and 16 mM of H2O2 concentrations at applied potential of –0.15 V, and high reproducibility (RSD = 2.6%). The selectivity of the fabricated sensors was also evaluated by applying ascorbic acid, glucose, and lactose separately onto the sensor in order to see if the sensor ourput is affected by one of them and the sensor output was not affected. In conclusion, the proposed PdCu/LIG electrode based H₂O₂ sensor seems to be suitable H2O2 sensor in various applications.