Electrochemical anodic oxidation of nitrogen doped carbon nanowall films: X-ray photoelectron and Micro-Raman spectroscopy study

► Surface oxidation and morphology modification of CNW films was controlled. ► The CNW specific capacitance was enhanced in ranges ([0-1] and [0-1.5] vs. SCE). ► Conversion of pyridinic nitrogen to pyridonic nitrogen upon cycling is revealed.