Structure and Sensing Properties of Nanostructured SnO2–In2O3 Composites Synthesized by the Impregnation Method

The structure and sensing properties of SnO2–In2O3 composites synthesized by the impregnation method are studied. These composites consist of In2O3 nanocrystals comprising SnO2 nanoclusters with a size of 5–7 nm on their surface. Using energy-dispersive X-ray spectroscopy, it is found that the SnO2 nanoclusters contain indium ions, which provide an increase in the number of catalytically active oxygen vacancies in them. The maximum efficiency of the synthesized composites for hydrogen detection in air is achieved at a SnO2 content in the composite of about 40 wt %. In this case, the high sensor sensitivity of the composite is attributed to the catalytic activity of SnO2 clusters containing indium ions and the high specific surface area of SnO2 aggregates, which provide the conductivity of the composite.