Preparation of macroporous SnO2 films using PMMA microspheres and their sensing properties to NOx and H2

Among the films prepared, mp-SnO2(P-250) exhibited the largest response to NO and NO2 in air at 225 °C, whereas its response transients were relatively slow, indicating low adsorption and desorption speeds of negatively charged chemisorbed NOx species on the SnO2 surface. On the other hand, mp-SnO2(P-800) showed the largest H2 response among the sensors at temperatures higher than 400 °C. It has been revealed that the thickness and porous structure of the SnO2 thick films are important factors to determine the sensing properties to NO2 and H2.