JIAO Wanli，ZHANG Lei
(School of Material Science and Engineering, Shandong University of Technology, Zibo 255049, Shandong, China)

Abstract: Due to the importance of morphology of nanoparticles to gas-sensing performance, flower-like SnO₂ nanopowders were prepared by a hydrothermal method, and the effects of pH value, hydrothermal temperature/time, and surfactants on crystal structure and morphology of the SnO₂ nanopowders were investigated. The crystal structure and morphology of the samples were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results indicated in the absence of surfactants, the rutile phase SnO₂ nano particles were of flower-like structure, consisting of nano-rods with the diameter of 40 nm and the length of 100 nm, when the pH value was 4, the hydrothermal temperature and time were 220 °C and 12 h, respectively. The surfactants changed the conglomeration growth morphology of SnO₂ nano-rods. The SnO₂ sensor has a better response, up to 6.5, for 70 μL·L^-1 ethanol gas at the optimal working temperature, 300 °C. The fast response time and recovery time are 2 s and 20 s, respectively.

Key words: SnO₂ nanopowders; hydrothermal method; flower-like structure; surfactant; gas-sensing performance