Amperometric Oxygen Sensor Based on Bimetallic Pd-V/C/Nafion Electrode

A novel oxygen sensor based on bimetallic Pd-V/C/Nafion electrode was developed. Carbon-supported bimetallic Pd-V nanoparticles were prepared by chemical reduction method at low temperature and sprayed on the Nafion membrane as working electrode. Their morphologies, compositional and structural properties were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), thermogravimetric analysis (TGA) and x-ray diffraction (XRD). Chemical reduction conditions including reducing agents and pH values for maximum catalytic efficiency, electrode selectivity, and reproducibility were discussed. Results showed that the optimal operating condition to generate the bimetallic Pd-V/C/Nafion electrode was using sodium borohydride as reducing agent at pH 4. The Pd₆V₄/C/Nafion electrode with face-centered cubic (fcc) structure exhibited the highest sensitivity of 7.42 µA/ppm·cm². It has a linear relationship between response current and oxygen concentration in the detection range from 100 to 1000 ppm. The sensor also displayed good selectivity and reproducibility.