LIU Jianhua, WANG Bingshan
(Department of Bio-chemistry of Jingdezhen University, Jingdezhen 333000, Jiangxi, China)

Abstract: ZnSnO₃ nanosheets and monodisperse Pt nanocrystals sol were first synthesized by hydrothermal method and reflux reduction method respectively, and then the precious metal Pt nanocrystals were assembled onZnSnO₃ nanosheets by a chemical self-assembly method.X-ray diffraction, scanning electron microscopy and high resolution transmission electron microscopy have been employed to characterize the crystal structure and morphology of the as-synthesized Pt/ZnSnO₃ anosheets composites. The results show that Pt nanocrystals were successfully loaded on ZnSnO₃ nanosheets by chemical self-assembly method, and also achieved relatively uniform distribution. Through the controlled addition of monodisperse Pt nanocrystals sol, different distribution density of Pt nanocrystals on Pt/ZnSnO₃  nanosheets can also be obtained. The as-fabricated Pt/ZZnSnO₃ nanosheets-based sensor composites with different Pt content were tested. Results showed that the nano Pt/ZnSnO₃  composite with 0.4% of Pt has the best sensing properties at the optimal working temperature of 300 ℃, and has good response to 0.1 ppm ethanol and 0.3 ppm formaldehyde. When the concentration of ethanol and formaldehyde is 10 ppm, it sensitivity was 50.9 and 15.3 respectively. The detection limit, sensitivity, selectivity and so on are improved greatly compared with those of pure ZnSnO₃  nanosheets.

Key words: chemical self-assembly; Pt- nanocrystals; ZnSnO₃ nanosheets; gas-sensing properties