Gas Sensing Properties of Size Varying CoFe2O4 Nanoparticles

This paper reports on the gas sensing properties of CoFe2O4 nanoparticles toward liquefied petroleum gas, ethanol, and ammonia. The gas response of was studied as a function of the particle size, the temperature, and the gas flow rate. The gas response was found to attain a maximum at an intermediate temperature in the order of 250 degrees C and to drop off toward higher and lower temperatures. The maximum gas response was found to increase as the particle size is reduced from 28.6 to 5.8 nm. It was further observed that the gas response increases linearly as the gas flow rate is increased. The response and recovery time constants were also observed to be flow-rate-dependent: whereas the response times decreased with the gas flow rate, the recovery time constants increased.