Effect of Ag+-doped on the Conductance and Gas-Sensing Properties of CdFe2O4

CdFe2O4and its Ag+-doped nano-powders were prepared by sol-gel method, the preparation conditions, phase constituents, microstructures, conductance and gas-sensing properties were also investigated. The results show that Cd1-xAgxFe2O4(0≤x≤0.04) solid solution nano-materials can be obtained when gel powder is calcined for 2h at 800℃, which is made from preheating gels at 350℃for 2hr and gets rid of surviving lemon acid. Measuring conductance shows that the material assumes behavior of the surface-resistance-controlled n-type semiconductor because of ionization of defect AgCd×(→AgCd′+ h·). The positive holes nullify free electrons (h·+ e′→null). The conductance of Ag+-doped solid solution is much lower than that of pure CdFe2O4at same temperature; Sensitivity of the element made from Cd0.98Ag0.02Fe2O4to 45μmol/L C2H5OH is 11 times larger than the petrol interfering gas of same concentration at 330℃. It is hoped to develop a new type information sensitive material of C2H5OH.