A novel nonenzymatic electrochemical sensor for the detection of hydrogen peroxide (H2O2) was developed based on free-standing nitrogen-doped carbon nanoparticles-embedded carbon nanofibers (NCNPFs) film, which were prepared by the carbonization of electrospun polypyrrole nanoparticles/polyacrylonitrile (PPy NPs/PAN) composite nanofibers. A series of NCNPFs-x samples with different mass concentration of PPy NPs to PAN (wt.%) were prepared. When the PPy NPs precursor is 12 wt.%, large amount of resulting NCNPs are embedded uniformly in NCNFs substrate without obvious aggregation. The as-obtained NCNPFs-12 wt.% has smaller diameter, higher content of pyrrolic-N and more defective sites, which result in high electrocatalytic activity for H2O2 reduction. The NCNPFs-12 wt.%-based H2O2 sensor shows a fast amperometric response within 2 s, and a wide linear range of 5.0 x 10(-6) to 2.7 x 10(-2) M with a high sensitivity of 383.9 mu A mu M-1 cm(-2). In addition, this nonenzymatic sensor displays good selectivity, high reproducibility and long-term stability. Because of the remarkable analytical performances, the NCNPFs-12 wt.%-based electrochemical sensor shows potential applications for the detection of H2O2 in human serum and disinfectant samples with satisfactory results. (C) 2015 Elsevier B.V. All rights reserved.