Au decorated In2O3 hollow nanospheres: A novel sensing material toward amine

This study demonstrates a hollow structure constructed by Au nanoparticles decorated on the surface of the In2O3 hollow nanospheres. This structure is prepared via calcination of solid organic precursors and in-situ reduction of Au nanoparticles on the metal oxide surface. The In2O3 hollow nanospheres are with the diameter of (similar to)200 nm and the shell thickness of 30 nm, while the Au nanoparticles on the surface of In2O3 hollow spheres are with the size of (similar to)10 nm. XPS indicates that the Au modification can increase the deficient oxygen vacancy ratio, and the presence of the positive Au ions (Au delta(+)) in the composites helps to trap the electrons and further improve the sensing performance. The gas sensing tests indicate that the Au decorated In2O3 hollow nanocomposites show excellent sensitivity (26.3 of 100 ppm) and selectivity toward 1-butylamine at the optimized temperature of 340 degrees C. The decoration of Au nanoparticles can lower the optimized working temperature and shorten the response/recovery times. The enhanced sensing mechanism can be attributed to electronic and chemical sensitization. The decoration of Au nanoparticles on the In2O3 surface can cause the Schottky barrier at the interface. The existence of positive Au ions can boost the barrier by trapping extra electrons. These results tender the promising hollow structure for sensing organic amine vapor in field-based use.