An in-situ electrochemical activation method was developed to activate the carbon fiber paper (CFP) for the highly efficient concentrated HNO3 reduction. The defects and heteroatoms were introduced onto the surface of carbon fiber resulting in a significant improvement in the reactivity. Furthermore, the surface wettability of electrode was adjusted to enhance the accessibility of the active surface. Owing to these advantages, the activated-CFP electrode exhibits a higher current density (464.1 mAcm(-2)) for the electroreduction of 4M HNO3 compared to the conventional Pt electrodes (75.39 mAcm(-2)). Based on scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and contact angle analysis, the HNO3 reduction mechanism on the activated CFP electrode was discussed. High activity as well as excellent electrochemical and chemical stability in the concentrated HNO3 make the activated-CFP as an effective alternative for noble-metal electrode in the future industrial applications. (c) 2018 Elsevier Ltd. All rights reserved.