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

Abstract

The activity of heterogeneous photocatalytic H2O2 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 (Fe1‐Nv/CN, single Fe atoms dispersed on carbon nitride with abundant nitrogen vacancies) for the activation of H2O2 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 H2O2 conversion efficiency. Therefore, the optimized single atom catalyst exhibiting a higher ciprofloxacin degradation activity, which was up to 18 times that of pristine CN.

A Unique Fe–N4 Coordination System Enabling Transformation of Oxygen into Superoxide for Photocatalytic CH Activation with High Efficiency and Selectivity

“…The same results are displayed in the Fe 2p XPS spectrum (Figure S7, Supporting Information). [49][50][51] The N 1s XPS spectrum of SA-Fe-TCN features three peaks at 395.1, 396.4, and 397.8 eV (Figure 3b). The first two peaks are typically found in CN and can be assigned to pyrrolic and pyridinic N, respectively.…”

Recent Advances in ZIF‐Derived Atomic Metal–N–C Electrocatalysts for Oxygen Reduction Reaction: Synthetic Strategies, Active Centers, and Stabilities

“…[ 43,44 ] However, the Fenton‐like reactions that occur between Fe 2+ and H 2 O 2 generating active free radicals is a severe concern, which likely causes the performance decline of the electrocatalysts and degradation of organic ionomers within electrodes. [ 45 ]…”

“…Generally, there are two kinds of commonly used strategies: (i) local coordination by adjusting the center metal structure, the introduction of impurity atoms, the synergy between dual‐ or multi‐metals, creating more edge carrying M–N x sites, enhancing the intrinsic activity of atomic metal active site; [ 53,54,64,68,80,108,122,123 ] and (ii) stabilizing individual metal site by improving the interactions between metal atoms and support, introducing additional defects or dopants, and using spatial constraint strategies to increase the amount of atomic metal site. [ 6,9,11,13–16,45,49 51,82,97,100,102,103,105,110,112,118,127,129 ]…”

Electronic Metal‐Support Interaction Directing the Design of Fe(III)‐Based Catalysts for Efficient Advanced Oxidation Processes by Dual Reaction Paths

“…Rapid and efficient elimination of anthropogenic organic pollutants in various types of wastewaters is of great significance to deal with the ever‐growing environmental pollution and the scarcity of fresh water resources. [ 1 ] Various treatment methods, including adsorption, [ 2 ] ultrafiltration, [ 3 ] flocculation, [ 4 ] biological methods, [ 5 ] photoelectrocatalysis, [ 6,7 ] and advanced oxidation processes (AOPs), [ 8–10 ] have been developed to deal with contaminated water. Among them, the radical‐based AOPs, especially the hydroxyl radicals (•OH) and sulfate radicals (SO 4 •− )‐based AOPs which are commonly generated by absorbing electrons from ferrous/ferric (Fe(II)/Fe(III)) redox cycle, have received increasing attention.…”

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significance to deal with the ever-growing environmental pollution and the scarcity of fresh water resources. [1] Various treatment methods, including adsorption, [2] ultrafiltration, [3] flocculation, [4] biological methods, [5] photoelectrocatalysis, [6,7] and advanced oxidation processes (AOPs), [8][9][10] have been developed to deal with contaminated water. Among them, the radical-based AOPs, especially the hydroxyl radicals (•OH) and sulfate radicals (SO 4•−

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