Development of Enzymatic Ethanol Sensor Based on PdCu Electrodeposited Laser Induced Graphene Electrode

This paper presents fabrication and characterization of an ethanol sensor whose working electrode (W.E.) is made consists of electrodeposited PdCu on laser induced graphene (LIG) layer and drop-casted alcohol oxidase (AOx) enzyme. AOx reacts with ethanol to generate hydrogen peroxide and the electrodeposited PdCu works as an electrocatalyst of hydrogen peroxide in order to increase amperometric output current. The optimum conditions for the ratio between Pd and Cu, the drop-casted AOx amount, the pH value of PBS have been obtained by varying the fabrication conditions and comparing the output results. Field emission scanning electron microscope (FE-SEM) and Raman spectroscopy were used to confirm LIG electrode formation. Also, Energy-dispersive X-ray spectroscopy (EDS) was performed to verify the ratio of the electrodeposited Pd and Cu. Cyclic voltammetry (CV) analysis of the W.E. showed that the peak reduction current occurs at-0.045 V. and this voltage was chosen as an applied voltage in amperometric measurement. Electrochemical impedance spectroscopy (EIS) shows that the charge transfer resistance of the PdCu deposited LIG W.E. is lower than the bare LIG W.E., which also shows the output current accordingly. Chronoamperometric response of the fabricated sensor was measured at various ethanol concentrations in range of 0-12 mM, and the linear sensitivity was 17.99 ?mM-1cm-2. which is similar or better than those of the recently reported other ethanol sensors.