In this work, catalytic Rh2O3-functionalized WO3 nanofibers (NFs) were synthesized via an electrospinning route and used as a highly selective acetone-sensing layer for potential diagnosis of diabetes. Catalytic rhodium nanoparticles (Rh NPs) with average diameters of 5.0 +/- 0.52 nm, which were synthesized by the polyol process, were dispersed in water with W precursor and poly(vinylpyrrolidone) (PVP) for electrospinning. As-spun Rh NP-loaded W precursor/PVP composite NFs were calcined at 600 degrees C for 1 h in air atmosphere to achieve Rh2O3-decorated WO3 NFs. Microstructure evolution and chemical composition of Rh2O3-decorated WO3 NFs as a function of Rh-loading amounts, i.e., 0.01 wt%, 0.05 wt%, 0.10 wt%, and 0.15 wt%, were examined using energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The mean size (30 nm) of the WO3 crystallites in Rh2O3-decorated WO3 NFs was much smaller than that (60 nm) of the WO3 crystallites in pristine WO3 NFs. The Rh2O3-decorated WO3 NFs showed outstanding acetone (CH3COCH3) sensing response (R-air/R-gas = 41.2 to 5 ppm), which was 4.6 times higher than the response (R-air/R-gas = 9.0 to 5 ppm) of pristine WO3 NFs at highly humid atmosphere (95% RH). In addition, superior acetone cross-sensitivity of the Rh2O3-decorated WO3 NFs was observed in other interfering gases such as pentane (n-C5H12), ammonia (NH3), toluene (C6H5CH3), carbon monoxide (CO), and ethanol (C2H5OH) at 5 ppm. These results are highly promising for the accurate and selective detection of acetone in exhaled breath for potential diagnosis of diabetes. (C) 2015 Elsevier B.V. All rights reserved.