Nano-sized PdO loaded SnO2 nanoparticles by reverse micelle method for highly sensitive CO gas sensor

A reverse micelle method was investigated for preparing nano-sized PdO loaded on SnO2 nanoparticles. PdO–SnO2 nano-composite was prepared by precipitating Pd(OH)2 and Sn(OH)4 inside a reverse micelle. The microstructure and the gas sensing properties of obtained nanoparticles were investigated. Although the particle size of SnO2 was as same as ca. 10 nm at each observed sample, the particle size of PdO got larger as increasing with loading amount of PdO because of agglomeration of PdO nanoparticles each other. As a result of the gas sensing measurement, it was found that the particle size of PdO on SnO2 nanoparticle influences the gas sensing property closely. That is, the sensor response declined gradually with increasing the particle size of PdO although the maximum of the sensor response was obtained in PdO = 0.1 mol%. In this method, small amount of PdO loading can be achieved as compared with PdO-loaded SnO2 sensor prepared by the conventional impregnation method.