Formation of large pores and their effect on electrical properties of SnO2 gas sensors

The effect of large pores on electrical properties of SnO2 gas sensors has been investigated. Large intergranular pores of 10-20 μm diameter were created in SnO2 gas sensors by adding starch powder in concentrations from 0 to 15 wt.%. Addition of starch powder did not change sintering behavior and resultant microstructure except for the formation of large pores. Gas sensitivity increased with starch addition. This result was attributed to enhanced diffusion of gases into the bulk SnO2 through the created large pores. Introduction of large pores in a bulk SnO2 matrix by adding starch can be a simple and useful way of microstructure control and sensitivity enhancement.