CO gas sensing properties of In4Sn3O12 and TeO2 composite nanoparticle sensors.

A simple hydrothermal route was used to synthesize In4Sn3O12 nanoparticles and In4Sn3O12-TeO2 composite nanoparticles, with In(C2H3O2)3, SnCl4, and TeCl4 as the starting materials. The structure and morphology of the synthesized nanoparticles were examined by X-ray diffraction and scanning electron microscopy (SEM), respectively. The gas-sensing properties of the pure and composite nanoparticles toward CO gas were examined at different concentrations (5-100ppm) of CO gas at different temperatures (100-300°C). SEM observation revealed that the composite nanoparticles had a uniform shape and size. The sensor based on the In4Sn3O12-TeO2 composite nanoparticles showed stronger response to CO than its pure In4Sn3O12 counterpart. The response of the In4Sn3O12-TeO2 composite-nanoparticle sensor to 100ppm of CO at 200°C was 10.21, whereas the maximum response of the In4Sn3O12 nanoparticle sensor was 2.78 under the same conditions. Furthermore, the response time of the composite sensor was 19.73s under these conditions, which is less than one-third of that of the In4Sn3O12 sensor. The improved sensing performance of the In4Sn3O12-TeO2 nanocomposite sensor is attributed to the enhanced modulation of the potential barrier height at the In4Sn3O12-TeO2 interface, the stronger oxygen adsorption of p-type TeO2, and the formation of preferential adsorption sites.