Effect of interaction between components of In2O3-CeO2 and SnO2-CeO2 nanocomposites on structure and sensing properties

The structure and conductometric sensing properties to hydrogen of In2O3-CeO2 and SnO2-CeO2 nanocomposites were investigated. Addition of small amounts of CeO2 to In2O3 nanocrystals is shown to result in a significant increase in the sensor response. On the other hand, addition of CeO2 to SnO2 matrix produces a sharp decrease in the sensor response, and at 3 wt% CeO2 concentration, the response of the SnO2-CeO2 composite to hydrogen is practically absent. The difference between the sensor response of In2O3-CeO2 and SnO2-CeO2 composites is shown to be mainly due to the different interactions between the CeO2 additives and the In2O3 or SnO2 matrix crystals in the composites. The probable mechanisms of the CeO2 effect on sensor response of the composites are discussed.