Fabrication of highly sensitive and selective acetone sensor using (p)-Co3O4 nanoparticle-decorated (n)-ZnO nanowires

Abstract (p)-Co3O4 nanoparticle-decorated (n)-ZnO nanowires were synthesized by two step process. ZnO nanowires and Co3O4 nanoparitcles were synthesized using a vapor-liquid-solid method and hydrothermal method, respectively. To decorate Co3O4 nanoparticles on ZnO nanowires, several amount of Co3O4 nanoparticle-suspended solution was dropped to ZnO nanowires, and this process was repeated to several times to find optimum amount of Co3O4 nanoparticles. As a result, Gas sensing response of ZnO nanowire-based sensor presented 1.73, 2.44, 3.07, 4.09, and 5.13 when exposed to 0.1 ppm, 0.5 ppm 1 ppm, 5 ppm, and 10 ppm acetone gas, respectively, whereas presented 5.38, 10.1, 15.81, 31.85, and 43.86 in case of three times of Co3O4 nanoparticle-decorated ZnO nanowire-based sensor to exposed to same condition of gas. In this paper, detailed method for synthesis of (p)-Co3O4 nanoparticle-decorated (n)-ZnO nanowires were introduced, and its enhanced acetone sensing mechanisms followed by decoration of optimum amount of Co3O4 nanoparticles on ZnO nanowires were discussed.