Two-step solid-state synthesis of tin oxide and its gas-sensing property

Tin oxide (SnO2) nanocrystals have been synthesized by two-step solid-state reactions. In the first step, the SnO fine particles are synthesized from the reaction of SnCl2·2H2O precursor with KOH in the size range of ca. 500 nm. Then the fine particles are oxidized into nano-sized SnO2 crystals with O2. It is an environment friendly, convenient, inexpensive and efficient preparation of SnO2 nanocrystals with grain size of ca. 20 nm. The prepared SnO2-based gas sensors have an excellent ability of discriminating EtOH from gasoline.