Enhancement in room-temperature ammonia sensor activity of size-reduced cobalt ferrite nanoparticles on γ-irradiation

The cobalt ferrite (CoFe2O4) nanoparticle sensors, synthesized using cost-effective sol-gel auto-combustion method, are irradiated with 2 and 5 kGy γ-doses. Effect of γ-irradiation on the structure, morphology and porosity is studied initially and in the later stage, methanol, acetone, ammonia, ethanol and toluene volatile organic gases are exposed for monitoring their selectivity and sensitivity with pristine and γ-irradiated CoFe2O4 nanoparticle-pellet sensors. The 5 kGy γ-irradiated CoFe2O4 sensor reveals 70% response for ammonia (100 ppm) gas, with high selectivity and room-temperature chemical and environmental stabilities. For knowing the changes in the structure, morphology, porosity and gas sensing performance of CoFe2O4 sensors on γ-irradiation theoretical model has also been proposed and explored. Proposed γ-irradiation approach can be used for enhancing the sensitivity of other gas sensors at room-temperature.