Electrospinning is a very versatile and efficient method of fabricating nanofibers with the desired properties. Polyvinylpyrrolidone (PVP) in ethanol solution was electrospun into nanofibers and used as a precursor for the preparation of carbon nanofibers. Cobalt chloride was also incorporated with PVP nanofibers to produce carbon nanofiber composites with enhanced electrical conductivity and electrochemical properties. The surface morphology and physical properties of the electrospun nanofibers, carbonized nanofibers, and their composites were observed by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The electrochemical behavior of the carbon nanofiber composites was studied by drop-casting on a working surface of the screen-printed carbon electrode and examined by cyclic voltammetry and electrochemical impedance spectroscopy. The results indicated that carbon nanofiber composites were decorated with cobalt nanoparticles and enhanced the charge-transfer efficiency on the electrode surface. (C) 2017 Wiley Periodicals, Inc.