CO₂ gas sensing properties of Na₃BiO₄-Bi₂O₃ mixed oxide nanostructures

In this paper, we report Na3BiO4-Bi2O3 mixed oxide nanoplates for carbon dioxide gas sensing applications. These nanoplates have been synthesized using electrochemical deposition with potentiostatic mode on ITO substrate and characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to analyze their surface morphology and structure. SEM study shows the presence of horizontally aligned nanoplates stacked on top of one another (thickness ≈ 40 to 75 nm). XRD pattern shows the presence of monoclinic Na3BiO4 and Bi2O3. The gas percentage response is evaluated by measuring the change in electrical resistance of the nanoplates in the presence of carbon dioxide for different pressures at 50 °C, 75 °C, and 100 °C. Percentage response of more than 100% is seen at 30 psi gas pressure which increases to ≈ 277% at 90 psi at 100^◦C.