Preparation of near room temperature gas sensor based on regular octahedral porous ZnO/SnO2 composite

Abstract

ZnO/SnO 2 often is used as the gas sensitive materials, but the gas sensors based on ZnO/SnO 2 shows the gas sensing property at the higher temperature because of its much higher initial resistance. In this study, porous ZnO/SnO 2 material with regular octahedral structure was successfully prepared, and the ZnO was wrapped into SnO 2 to form the heterostructure which improved the separation efficiency of electron-hole to decrease the initial resistance in the prepared materials. The prepared material showed much better gas sensing property at the room and near-room temperatures (35 °C, NRT). The response of the octahedral ZnO/SnO 2 to 100 ppm ethanol gas was 17.8, and the response time was only 1 s at NRT. Moreover, the prepared gas sensor had the much better gas selectivity to ethanol gas detection. The excellent gas sensing performance could be attributed to which the porous structure, the large specific surface area and the n-n heterojunctions could provide the more gas adsorption active sites and the electronic transmission channels to make the gas sensor with the better gas sensitive response to the target gas. • Regular octahedral ZnO/SnO 2 composite is prepared. • This sensor exhibits the higher gas-sensitive property at the lower operating temperature (35 °C). • The composite has high response speed and fast response/recovery process. • The composite has the larger specific surface area and the n-n heterojunction.