Fig. 3From: Enhanced Capacitive Performance of N-Doped Activated Carbon from Petroleum Coke by Combining Ammoxidation with KOH Activation a FT-IR spectra of NOAC at different temperatures. b XPS survey spectra of NOAC400. High-resolution XPS spectra of N 1s peak (c) and O 1s peak (d) for NOAC400Back to article page