The effect of surface morphology on the response of Fe2O3-loaded vanadium oxide nanotubes gas sensor

The effect of surface morphology on the response of an ethanol sensor based on vanadium nanotubes surface loaded with Fe2O3 nanoparticles (Fe2O3/VONTs) was investigated in this work. The particle size of Fe2O3 loaded on VONTs was varied by using novel citric acid-assisted hydrothermal method. In the synthesis progress, citric acid was used as a surfactant and chelate agent, which ensured the growth of a uniform Fe2O3 loading on the nanotubes surface. The ethanol sensing properties was then measured for these Fe2O3/VONTs at 230–300 °C. The results showed that the sensor response increased with the particles size and the loading amount of Fe2O3. It appears that the load of Fe2O3 on the VONTs surface increases the concentration of oxygen vacancies and decreases the concentration of free electrons. The effects of morphology on the sensor resistance were interpreted in terms of the Debye length and the difference in the number of active sites.