Preparation and characterization of hollandite thin film

Thin films of hollandite-type KxGaxSn8−xO16 (KGSO) were prepared by spin-coating method. Favorite thin films were obtained using YSZ substrate. Those are colorless, transparent and smooth, and about 100–150 nm thick at minimum, consisting of KGSO primary particles with a few tens of nanometers in average size. The adsorption behavior of NO on the thin film was examined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The films were preheated at 968 K in a mixture gas of N2 and O2 prior to NO adsorption. As the oxygen ratio in the mixture gas increased up to 40%, the absorption bands came to occur and got stronger in the range from 1000 to 1500 cm−1. Those bands were assigned to NO2 species in chelating and nitrito form, referring to the literature about NO on La2O3. It was found that the coexistence of oxygen remarkably improved the adsorption ability of NO on KGSO thin films.