Visible-light-assisted generation of high-valent iron-oxo species anchored axially on g-C3N4 for efficient degradation of organic pollutants

As highly active species, in theory, hydroxyl radicals ( OH) can move freely and destroy almost all organic compounds, including catalysts with a conjugate structure. Therefore, a system that can generate oxidative species with a high activity, but where the active species is anchored to avoid autooxidation, is urgently required. In this work, we fabricated a novel visible-light-assisted advanced oxidation process based on high-valent iron species (Fe(IV) O) over graphitic carbon nitride (g-C 3 N 4 ) that was coordinated to iron hexadecachlorophthalocyanine (FePcCl 16 ) through imidazole ligands (IMD). Under visible-light excitation, the phthalocyanine ring of the g-C 3 N 4 -IMD-FePcCl 16 /hydrogen peroxide (H 2 O 2 ) can be motivated to an excited state FePcCl 16 ∗ , in which active H 2 O 2 and the generation of anchored Fe(IV) O species are used for the degradation of carbamazepine (CBZ). Because the molecular movement of transient Fe(IV) O species is restricted, the possibility of oxidative collision is minimized, which provides good stability. An analysis of the electron paramagnetic resonance, gas chromatography/mass spectrometry, photoluminescence spectra, periodic on/off photocurrent density response and the photo-assisted catalytic active experiments, indicates that the rapid generation of Fe(IV) O species occurs as the catalyst contacts the H 2 O 2 , which inhibits the conduction-band electrons of the g-C 3 N 4 from reacting with H 2 O 2 and generating OH. This study provides insight into the construction of suitable structures that will enhance visible-light-assisted catalytic oxidation activity and allow for the fabrication of an anchored highly active species.