Effect of MgO Doping on the Conductance and Gas-sensing Properties of In2 O3

Micro-powder of In2O3 doped with MgO is prepared by chemical coprecipitation, effects of Mg2+ on the conductance and gas-sensing properties of In2O3 was investigated. The results demonstrated that limite solid solution In2-xMgxO3(0≤x≤0.40) can be formed between MgO and In2O3. Positive protons produced i the ionization process of MgIn×can null the electrons in the conductive gap and this decrease the electrical conductance of the micro-powder significantly. The sensor based on then(Mg2+)∶n(In3+)=1∶2 chemical coprecip tation raw powder sintered at 900℃ for 4 h, to 45μmol/L C2H5OH can be 102.5 at 320~370℃. This is twelve times more than that of same concentration petrol.