Abstract
Urea-derived graphitic carbon nitride (g-C₃N₄) underwent to chemical treatment in a strongly oxidizing H₂SO₄/HNO₃/H₂O₂ environment, followed by dialysis against water. XRD and SEM measurements revealed significant disruption of the layered polymeric framework, including loss of hydrogen-bond-mediated order, partial depolymerization into melem-based units, and the formation of rod-like melem-hydrate superstructures. FTIR spectra indicated that chemical treatment resulted in the loss of the heptazine structure and emergence of melem/triazine vibrations. Consistent disruption of the C–N framework was also observed in XPS spectra, which showed a reduced contribution of nitrogen species associated with inter-triazine bridging. Mott–Schottky analysis yielded potential values suggesting the presence of additional electronic states in the chemically treated sample. This aligns with EPR spin-trapping results, which showed approximately a 2.5-fold decrease in superoxide radical anion generation upon visible light irradiation compared to the parent compound.