Preparation and Gas Sensor Application of Ceramic Particles with Submicron-Size Spherical Macropores

摘要

Porous SnO{sub}2 and In{sub}2O{sub}3 powders (pr-SnO{sub}2 and pr-In{sub}2O{sub}3, respectively) were prepared by pyrolysis of atomized SnCI{sub}4 and In(NO{sub}3){sub}3 aqueous solutions containing polymethylmethacrylate (PMMA) microspheres (150 nm or 250 nm in diameter) as a template. Spherical macropores reflecting the morphology of the PMMA template could be formed in the pr-SnO{sub}2 and pr-In{sub}2O{sub}3 powders. H{sub}2 response of the pr-SnO{sub}2 was low, but addition of Pt was effective for improving the H{sub}2 response of the pr-SnO{sub}2. In addition, simultaneous loading of Pt and doping of Sb{sub}2O{sub}5 resulted in the largest H{sub}2 response along with relatively low resistance in air. On the other hand, a pr-In{sub}2O{sub}3 sensor showed much higher NO{sub}2 response than a conventional In{sub}2O{sub}3 sensor, which was fabricated with the non-porous powder prepared by hydrolysis of indium nitrate by an ammonia solution. These results show that introduction of macropores into ceramic powder used for sensor materials is very effective for improving their sensing properties.