Co3O4-RuO2 composite nanofibers (NFs) were synthesized by an electrospinning method and were calcinated at 400 degrees C for 1 hr in air. Scanning electron microscopy and high-resolution transmission electron microscopy (HRTEM) examinations show that all the synthesized NFs have uniform surface morphology and their diameters are in the range of similar to 30-similar to 70 nm. X-ray diffraction (XRD) results show that crystalline Co3O4 phase and RuO2 phase coexist in the composite NF matrix which is confirmed by X-ray photoemission spectroscopy. In addition, the HRTEM energy-dispersive X-ray spectroscopy mapping results show that the Co3O4 and RuO2 phases are uniformly distributed across the NF matrix. (C) 2010 Elsevier B.V. All rights reserved.