Fabrication and Photodegradation Application of Isopropanol-Functionalized Poly (Triazine Imide)

This study reported the fabrication and photodegradation application of surface-functionalized poly (triazine imide) (PTI). PTI was obtained through a single-step thermal decomposition process, followed by mild isopropanol (IPA) oxidation treatments at various temperatures. The PTI structure was retained after the surface functionalization; however, the crystallinity deteriorated. The IPA-treated samples exhibited carbon-to-nitrogen ratios similar to those exhibited by pristine PTI. Furthermore, they displayed the morphology of tetragonal tubes and layered nanosheets. Triazine units were confirmed by conducting Fourier transform infrared spectroscopy. The analyses of ¹³C cross-polarization magic angle spinning solid-state nuclear magnetic resonance and x-ray photoelectron spectroscopy validated the formation of functional groups of C=O and –COOH or –COOR on the PTI surface. After IPA oxidation at 120°C (IPA-120), the sample exhibited reliable photodegradation of methylene blue with a degradation rate constant (k) of approximately 0.01 min⁻¹, which was almost 2.5 times higher than that of pristine PTI. Our study revealed that a low recombination of photogenerated electron–hole pairs was crucial to induce synergistic photocatalysis; however, the sample also exhibited a high specific surface area, enhanced visible light absorption, and a reduced band gap (approximately 2.3 eV). Furthermore, the constructed energy band diagram supported the observations in the photodegradation and scavenger studies.