Effects of Addition of CuxO to Porous SnO2 Microspheres Prepared by Ultrasonic Spray Pyrolysis on Sensing Properties to Volatile Organic Compounds
Soichiro Torai, Taro Ueda, Kai Kamada, Takeo Hyodo, Yasuhiro Shimizu
Abstract
Porous (pr-)SnO2-based powders were synthesized by ultrasonic spray pyrolysis employing home-made polymethylmethacrylate (PMMA) microspheres (typical particle size: 70 nm in diameter), and effects of the CuxO addition to the pr-SnO2 powder on the acetone and toluene sensing properties were investigated. Well-developed spherical pores reflecting the morphology of the PMMA microsphere templates were formed in the SnO2-based powders, which were quite effective in enhancing the acetone and toluene responses. The 0.8 wt% Cu-added pr-SnO2 sensor showed the largest acetone response at 350 °C among all the sensors. Furthermore, we clarified that the addition of CuxO onto the pr-SnO2 decreased the concentration of carrier electrons and the acetone-oxidation activity, leading to the improvement of the acetone-sensing properties of the pr-SnO2 sensor.