Bi-functional co-sensitization of graphene oxide sheets and Ir nanoparticles on p-type Co3O4 nanofibers for selective acetone detection

Abstract

We report the highly sensitive and selective acetone detection achieved by sensitizing p-type Co3O4 nanofibers (NFs) with Ir nanoparticles (NPs) and graphene oxide (GO) sheets for potential diagnosis of diabetes. Co3O4 NFs mixed with Ir NPs (1 wt%, average particle size 6 nm) were further functionalized by GO sheets (1 wt%) to investigate the dual-sensitization effect on cross sensitivity for acetone, pentane, NO, NH3, CO, and NO2. These Ir- and GO-co-functionalized Co3O4 NF composites exhibited a high acetone response (R-gas/R-air = 2.29) at 5 ppm. This value was 58% and 36% greater than that of the pristine Co3O4 NFs (R-gas/R-air = 1.45) and Ir-functionalized Co3O4 NFs (R-gas/R-air = 1.69), respectively. The detection limit of Ir- and GO-co-functionalized Co3O4 NF sensors is predicted to be as low as 120 ppb, presenting the response value of 1.18 at 300 degrees C. Furthermore, superior acetone selectivity, in competition with interfering gases such as pentane, NO, NH3, CO, and NO2, was investigated. This work demonstrates that optimized co-sensitization of two catalysts (i.e., Ir NPs and GO sheets) on p-type metal oxide NFs enables the precise detection of exhaled breath gases for the diagnosis of diabetes.