Conduction mechanism and gas sensing properties of CoFe2O4 nanocomposite thick films for H2S gas

► Polycrystalline CoFe2O4 nanomaterials have been prepared by sol-gel citrate method for H2S gas detection. ► Conductivity was higher for 0.2 wt% Sm and 1 0 wt% Ni doped CoFe2O4. ► The sensor shows high degree of selectivity towards H2S gas at an operating temperature 200 °C.