Enhancement of the Sensing Properties of Chitosan Films as an Acetone Gas Sensor with the Addition of Tin Oxide (SnO2)

In this study, the sensing properties of the chitosan film sensor were successfully improved by adding tin oxide (SnO2). The addition of SnO2concentration to the chitosan solution was 0.01%, 0.05%, 0.1%, and 0.5% (w/v). The sensor is fabricated as a film using the electrodeposition method. The sensing properties of chitosan and chitosan-SnO2 film sensors were exposed to acetone gas with concentrations of 0.5; 1; 1.5; 2; 2.5; and 3 ppm. The testing results show that chitosan film's response and repeatability properties produced the highest output voltage of 514 mV at 1.5 ppm, while the lowest output voltage value was 499.72 at 0.5 ppm. The addition of SnO2 with the highest concentration of 0.5% increased the response and repeatability properties in the form of the highest output voltage to 569.34 mV at 3 ppm, while the SnO2 concentration of 0.01% resulted in the lowest sensor output voltage of 504.84 mV at 0.5 ppm. The reproducibility of chitosan film became better due to the addition of SnO2, which resulted in a low STDEV value of 0.005 compared to that of chitosan film without the addition of SnO2, namely 0.156. The sensitivity of the chitosan film added by SnO2 increased, indicated by the increase in the slope value of 17.142 compared to the chitosan film without the addition of SnO2, which was 1.82. The SEM characterization showed that adding SnO2 increased the number of pores formed on the film, which strengthened the ability to absorb acetone. This is also evidenced by the FTIR results, which show the presence of SnO2 in the peak range of the wavenumbers from 677-717 cm-1. Therefore, the chitosan film sensor with the addition of SnO2 concentration showed better-sensing properties than chitosan film, which could be applied as an acetone gas sensor.