Regulating Local Electron Density of Iron Single Sites by Introducing Nitrogen Vacancies for Efficient Photo‐Fenton Process

Abstract

The activity of heterogeneous photocatalytic H 2 O 2 activation in Fenton-like processes is closely related to the local electron density of reaction centre atoms. However, the recombination of electron-hole pairs arising from random charge transfer greatly restricts the oriented electron delivery to active center. Here we show a defect engineered iron single atom photocatalyst (Fe 1 -N v /CN, single Fe atoms dispersed on carbon nitride with abundant nitrogen vacancies) for the activation of H 2 O 2 under visible light irradiation. Based on DFT calculations and transient absorption spectroscopy results, the engineered nitrogen vacancies serve as the electron trap sites, which can directionally drive the electrons to concentrate on Fe atoms. The formation of highly concentrated electrons density at Fe sites significantly improves the H 2 O 2 conversion efficiency. Therefore, the optimized single atom catalyst exhibiting a higher ciprofloxacin degradation activity, which was up to 18 times that of pristine CN.

Slow-release synthesis of Cu single-atom catalysts with the optimized geometric structure and density of state distribution for Fenton-like catalysis

“…The as-synthesized Cu/NC-MMT also displayed a great superiority in both apparent reaction rate constant ( k obs , min −1 ) and mass activity of monatomic Cu (normalized k obs , min −1 g −1 Cu) for Fenton-like catalysis over numerous state-of-the-art reports, including Cu-C 3 N 4 , Cu 5 /FeS 2 , CoFe 2 O 4 /MoS 2 , and Fe 1 -NV/CN ( SI Appendix , Fig. S32 and Table S7 ) ( 44 , 49 – 51 ). Other factors such as pH, temperature, concentration, toxicity, and stability, which might affect the technical reliability, were further considered ( Fig.…”

Unraveling the Synergy Mechanism between Photocatalysis and Peroxymonosulfate Activation on a Co/Fe Bimetal-Doped Carbon Nitride

“…This conclusion is in good agreement with the aforementioned PL experimental results. In addition, the LUMOs in the Co-and Fe-doped g-C 3 N 4 are distributed in the corresponding metal element sites, indicating that the photogenerated electrons can directly interact with these sites, 12 thus realizing the synergy between photocatalysis and Fenton-like catalysis.…”

“…Graphitic carbon nitride (g-C 3 N 4 ), a conjugated polymer with semiconductor properties that can be excited by visible light, has shown great application potential in various environmental and energy catalysis fields. − In addition, the N elements with lone pairs of electrons on g-C 3 N 4 can easily coordinate with metal elements to form M–N x structures, thus forming stable atomically dispersed metal active sites and inhibiting the loss of metal elements. − Therefore, g-C 3 N 4 is an ideal support and platform for the fabrication and study of photo-Fenton-like catalysts. − Yet, due to the limited performance of traditional catalysts, various strategies have been applied to construct an efficient photo-Fenton-like catalyst, including constructing heterojunction, − doping, defect engineering, and so on. However, all of the reported works indicated that the degradation efficiency of pollutants was higher when photocatalysis and Fenton-like catalysis were employed simultaneously.…”