| Summary: | Three types of In<sub>2</sub>O<sub>3</sub> nanoparticles decorated with Au, Pd and Pt nanoparticles, respectively, were synthesized by thermal decomposition method, and the effects of metal nanoparticles on their phase, microstructure, chemical state, carrier types were investigated with XRD, SEM/TEM, and XPS. Additionally, sensing properties to CO gas, such as sensitivity, etc., were examined with sensing apparatus. Au-decorated In<sub>2</sub>O<sub>3</sub> nanoparticles exhibited the highest sensitivity to CO gas, with S = 5.59 at a 10 ppm CO gas concentration at 50 °C compared to Pd or Pt-decorated In<sub>2</sub>O<sub>3</sub> nanoparticles. This can be interpreted as a much higher adsorption of oxygen molecules on the In<sub>2</sub>O<sub>3</sub> surface due to the high oxygen vacancies in the In<sub>2</sub>O<sub>3</sub> lattice, which generates an electron depletion region in the outer layer of In<sub>2</sub>O<sub>3</sub> to sharply increase the resistance or the spill-over effect due to Au nanoparticles on In<sub>2</sub>O<sub>3</sub>. Au nanoparticles were observed in the TEM images and confirmed by XPS analysis.
|
|---|
