Superoxide radicals mediated by high-spin Fe catalysis for organic wastewater treatment.

Water resources are indispensable basic resources and important environmental carriers; the presence of organic contaminants in wastewater poses considerable risks to the health of both humans and ecosystems. Although the Fenton-like reactions using H2O2 as the oxidant to destroy organic pollutants are attractive, there are still challenges in improving reaction activity under neutral or even alkaline conditions. Herein, we designed a H2O2 activation pathway with O2•- as the main active species and elucidated that the spin interaction between Fe sites and coordinated O atoms effectively promotes the generation of the key intermediate Fe-*OOH. Furthermore, we successfully captured and analyzed the Fe-*OOH intermediate by in situ Raman spectroscopy. When applying FBOB to a continuous-flow reactor, CIP removal efficiency remained at around 90% within 600 min of continuous operation, achieving excellent efficiency, stability, and pH tolerance in removing pollutants.

Boron-Nitrogen-Edged Biomass-Derived Carbon: A Multifunctional Approach for Colorimetric Detection of H2O2, Flame Retardancy, and Triboelectric Nanogenerator.

Enhancing the concentration and type of nitrogen (N) dopants within the Sp2-carbon domain of carbon recycled from biomass sources is an efficient approach to mimic CNT, GO, and rGO to activate oxidants such as H2O2, excluding toxic chemicals and limiting reaction steps. However, monitoring the kind and concentration of N species in the Sp2-C domain is unlikely with thermal treatments only. A high temperature for graphitization reduces N moieties, leading to low electron density. This inhibits H2O2 adsorption and activation on catalyst surfaces. In this study, coffee waste (CW) is converted into B, N-doped biochar (BXNbY) using boric acid-assisted pyrolysis (H3BO3 mass = X and carbonization temperature = Y) under N2 to overcome the challenge. The B dopant regulates the concentration and type of N, provides Lewis's acid sites, and converts graphitic-N to pyridine-N in BXNbY. The optimized B3Nb900 exhibits excellent colorimetric sensing performance toward H2O2 with a low detection limit (36.9 nM) and high selectivity in the presence of many interferences and milk samples due to high pyridinic-N and Sp2 domain sizes. Interestingly, B enhances other properties of N-containing CW-derived carbon and introduces self-extinguishing and tribopositive properties. Hence, BXNbY-coated polyurethane foam shows excellent flame retardancy and energy harvesting performance.

Spatially Decoupled H2O2 Activation Pathways and Multi-Enzyme Activities in Rod-Shaped CeO2 with Implications for Facet Distribution.

CeO2, particularly in the shape of rod, has recently gained considerable attention for its ability to mimic peroxidase (POD) and haloperoxidase (HPO). However, this multi-enzyme activities unavoidably compete for H2O2 affecting its performance in relevant applications. The lack of consensus on facet distribution in rod-shaped CeO2 further complicates the establishment of structure-activity correlations, presenting challenges for progress in the field. In this study, the HPO-like activity of rod-shaped CeO2 is successfully enhanced while maintaining its POD-like activity through a facile post-calcination method. By studying the spatial distribution of these two activities and their exclusive H2O2 activation pathways on CeO2 surfaces, this study finds that the increased HPO-like activity originated from the newly exposed (111) surface at the tip of the shortened rods after calcination, while the unchanged POD-like activity is attributed to the retained (110) surface in their lateral area. These findings not only address facet distribution discrepancies commonly reported in the literature for rod-shaped CeO2 but also offer a simple approach to enhance its antibacterial performance. This work is expected to provide atomic insights into catalytic correlations and guide the design of nanozymes with improved activity and reaction specificity.

Constructing Nano-Heterostructure with Dual-Site to Boost H2O2 Activation and Regulate the Transformation of Free Radicals.

A major issue with Fenton-like reaction is the excessive consumption of H2O2 caused by the sluggish regeneration rate of low-valent metal, and how to improve the activation efficiency of H2O2 has become a key in current research. Herein, a nano-heterostructure catalyst (1.0-MnCu/C) based on nano-interface engineering is constructed by supporting Cu and MnO on carbon skeleton, and its kinetic rate for the degradation of tetracycline hydrochloride is 0.0436 min-1, which is 2.9 times higher than that of Cu/C system (0.0151 min-1). The enhancement of removal rate results from the introduced Mn species can aggregate and transfer electrons to Cu sites through the electron bridge Mn-N/O-Cu, thus preventing Cu2+ from oxidizing H2O2 to form O2 •-, and facilitating the reduction of Cu2+ and generating more reactive oxygen species (1O2 and ·OH) with stronger oxidation ability, resulting in H2O2 utilization efficiency is 1.9 times as much as that of Cu/C. Additionally, the good and stable practical application capacity in different bodies demonstrates that it has great potential for practical environmental remediation.

Regulating Surface Dipole Moments of TiO2 for the pH-Universal Cathodic Fenton-Like Process.

Although electro-Fenton (EF) processes can avoid the safety risks raised by concentrated hydrogen peroxide (H2O2), the Fe(III) reduction has always been either unstable or inefficient at high pH, resulting in catalyst deactivation and low selectivity of H2O2 activation for producing hydroxyl radicals (•OH). Herein, we provided a strategy to regulate the surface dipole moment of TiO2 by Fe anchoring (TiO2-Fe), which, in turn, substantially increased the H2O2 activation for •OH production. The TiO2-Fe catalyst could work at pH 4-10 and maintained considerable degradation efficiency for 10 cycles. Spectroscopic analysis and a theoretical study showed that the less polar Fe-O bond on TiO2-Fe could finely tune the polarity of H2O2 to alter its empty orbital distribution, contributing to better ciprofloxacin degradation activity within a broad pH range. We further verified the critical role of the weakened polarity of H2O2 on its homolysis into •OH by theoretically and experimentally investigating Cu-, Co-, Ni-, Mn-, and Mo-anchored TiO2. This concept offers an avenue for elaborate design of green, robust, and pH-universal cathodic Fenton-like catalysts and beyond.

Degradation of phenol by metal-free electro-fenton using a carbonyl-modified activated carbon cathode: Promoting simultaneous H2O2 generation and activation.

The low yield of hydrogen peroxide, narrow pH application range, and secondary pollution due to iron sludge precipitation are the major drawbacks of the electro-Fenton (EF) process. Metal-free electro-Fenton technology based on carbonaceous materials is a promising green pollutant degradation technology. Activated carbon cathodes enriched with carbonyl functional groups were prepared using a two-step annealing method for the degradation of phenol pollutants. The •OH in the activation process of H2O2 were identified using the EPR test technique. The action mechanism of carbonyl groups on H2O2 activation was investigated in conjunction with density functional theory (DFT) calculations. The EPR tests demonstrated that the modified activated carbon could promote the in-situ activation of H2O2 to •OH. And the results of material analysis and DFT showed that C=O could facilitate the activation of hydrogen peroxide through the electron transfer mechanism as an electron-donating group. Electrochemical tests showed that both the oxygen reduction activity and 2e-ORR selectivity of the modified activated carbons were significantly improved. Compared with the original activated carbon cathode and EF, the degradation efficiency of phenol in the ACNH-1000/GF cathode was increased by 58.10% and 45.61%, respectively. Compared with EF, ACNH-1000/GF metal-free electro-Fenton effectively expands the pH application range, and is proven to be less affected by solution initial pH, while avoiding secondary pollution. The metal-free electro-Fenton system can save more than a quarter of the cost of EF system. This study has a deep understanding of the reaction mechanism of the carbonyl modified activated carbon, and provides valuable insights for the design of metal-free catalysts, so as to promote its application in the degradation of organic pollutants.

Advanced Photodegradation of Azo Dye Methyl Orange Using H2O2-Activated Fe3O4@SiO2@ZnO Composite under UV Treatment.

The Fe3O4@SiO2@ZnO composite was synthesized via the simultaneous deposition of SiO2 and ZnO onto pre-prepared Fe3O4 nanoparticles. Physicochemical methods (TEM, EDXS, XRD, SEM, FTIR, PL, zeta potential measurements, and low-temperature nitrogen adsorption/desorption) revealed that the simultaneous deposition onto magnetite surfaces, up to 18 nm in size, results in the formation of an amorphous shell composed of a mixture of zinc and silicon oxides. This composite underwent modification to form Fe3O4@SiO2@ZnO*, achieved by activation with H2O2. The modified composite retained its structural integrity, but its surface groups underwent significant changes, exhibiting pronounced catalytic activity in the photodegradation of methyl orange under UV irradiation. It was capable of degrading 96% of this azo dye in 240 min, compared to the initial Fe3O4@SiO2@ZnO composite, which could remove only 11% under identical conditions. Fe3O4@SiO2@ZnO* demonstrated robust stability after three cycles of use in dye photodegradation. Furthermore, Fe3O4@SiO2@ZnO* exhibited decreased PL intensity, indicating an enhanced efficiency in electron-hole pair separation and a reduced recombination rate in the modified composite. The activation process diminishes the electron-hole (e-)/(h+) recombination and generates the potent oxidizing species, hydroxyl radicals (OH˙), on the photocatalyst surface, thereby playing a crucial role in the enhanced photodegradation efficiency of methyl orange with Fe3O4@SiO2@ZnO*.

Atomic-Layered Cu5 Nanoclusters on FeS2 with Dual Catalytic Sites for Efficient and Selective H2 O2 Activation.

Regulating the distribution of reactive oxygen species generated from H2 O2 activation is the prerequisite to ensuring the efficient and safe use of H2 O2 in the chemistry and life science fields. Herein, we demonstrate that constructing a dual Cu-Fe site through the self-assembly of single-atomic-layered Cu5 nanoclusters onto a FeS2 surface achieves selective H2 O2 activation with high efficiency. Unlike its unitary Cu or Fe counterpart, the dual Cu-Fe sites residing at the perimeter zone of the Cu5 /FeS2 interface facilitate H2 O2 adsorption and barrierless decomposition into ⋅OH via forming a bridging Cu-O-O-Fe complex. The robust in situ formation of ⋅OH governed by this atomic-layered catalyst enables the effective oxidation of several refractory toxic pollutants across a broad pH range, including alachlor, sulfadimidine, p-nitrobenzoic acid, p-chlorophenol, p-chloronitrobenzene. This work highlights the concept of building a dual catalytic site in manipulating selective H2 O2 activation on the surface molecular level towards efficient environmental control and beyond.

Remote Amino Acid Recognition Enables Effective Hydrogen Peroxide Activation at a Manganese Oxidation Catalyst.

Precise delivery of a proton plays a key role in O2 activation at iron oxygenases, enabling the crucial O-O cleavage step that generates the oxidizing high-valent metal-oxo species. Such a proton is delivered by acidic residues that may either directly bind the iron center or lie in its second coordination sphere. Herein, a supramolecular strategy for enzyme-like H2 O2 activation at a biologically inspired manganese catalyst, with a nearly stoichiometric amount (1-1.5 equiv) of a carboxylic acid is disclosed. Key for this strategy is the incorporation of an α,ω-amino acid in the second coordination sphere of a chiral catalyst via remote ammonium-crown ether recognition. The properly positioned carboxylic acid function enables effective activation of hydrogen peroxide, leading to catalytic asymmetric epoxidation. Modulation of both amino acid and catalyst structure can tune the efficiency and the enantioselectivity of the reaction, and a study on the oxidative degradation pathway of the system is presented.

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

The activity of heterogeneous photocatalytic H2 O2 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 H2 O2 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 H2 O2 conversion efficiency. Therefore, the optimized single atom catalyst exhibiting a higher ciprofloxacin degradation activity, which was up to 18 times that of pristine CN.

Directing a Non-Heme Iron(III)-Hydroperoxide Species on a Trifurcated Reactivity Pathway.

The reactivity of [FeIII (tpena)]2+ (tpena=N,N,N'-tris(2-pyridylmethyl)ethylenediamine-N'-acetate) as a catalyst for oxidation reactions depends on its ratio to the terminal oxidant H2 O2 and presence or absence of sacrificial substrates. The outcome can be switched between: 1) catalysed H2 O2 disproportionation, 2) selective catalytic oxidation of methanol or benzyl alcohol to the corresponding aldehyde, or 3) oxidative decomposition of the tpena ligand. A common mechanism is proposed involving homolytic O-O cleavage in the detected transient purple low-spin (S=1/2 ) [(tpenaH)FeIII O-OH]2+ . The resultant iron(IV) oxo and hydroxyl radical both participate in controllable hydrogen-atom transfer (HAT) reactions. Consistent with the presence of a weaker σ-donor carboxylate ligand, the most pronounced difference in the spectroscopic properties of [Fe(OOH)(tpenaH)]2+ and its conjugate base, [Fe(OO)(tpenaH)]+ , compared to non-heme iron(III) peroxide analogues supported by neutral multidentate N-only ligands, are slightly blue-shifted maxima of the visible absorption band assigned to ligand-to-metal charge-transfer (LMCT) transitions and, corroborating this, lower FeIII /FeII redox potentials for the pro-catalysts.

In situ single iron atom doping on Bi2WO6 monolayers triggers efficient photo-fenton reaction.

Developing an efficient photocatalytic system for hydrogen peroxide (H2O2) activation in Fenton-like processes holds significant promise for advancing water purification technologies. However, challenges such as high carrier recombination rates, limited active sites, and suboptimal H2O2 activation efficiency impede optimal performance. Here we show that single-iron-atom dispersed Bi2WO6 monolayers (SIAD-BWOM), designed through a facile hydrothermal approach, can offer abundant active sites for H2O2 activation. The SIAD-BWOM catalyst demonstrates superior photo-Fenton degradation capabilities, particularly for the persistent pesticide dinotefuran (DNF), showcasing its potential in addressing recalcitrant organic pollutants. We reveal that the incorporation of iron atoms in place of tungsten within the electron-rich [WO4]2- layers significantly facilitates electron transfer processes and boosts the Fe(II)/Fe(III) cycle efficiency. Complementary experimental investigations and theoretical analyses further elucidate how the atomically dispersed iron induces lattice strain in the Bi2WO6 monolayer, thereby modulating the d-band center of iron to improve H2O2 adsorption and activation. Our research provides a practical framework for developing advanced photo-Fenton catalysts, which can be used to treat emerging and refractory organic pollutants more effectively.

Critical role of zero-valent iron in the efficient activation of H2O2 for 4-CP degradation by bimetallic peroxidase-like.

Peroxidase-like based on double transition metals have higher catalytic activity and are considered to have great potential for application in the field of pollutant degradation. First, in this paper, a novel Fe0-doped three-dimensional porous Fe0@FeMn-NC-like peroxidase was synthesized by a simple one-step thermal reduction method. The doping of manganese was able to reduce part of the iron in Fe-Mn binary oxides to Fe0 at high temperatures. In addition, Fe0@FeMn-NC has excellent peroxidase-like mimetic activity, and thus, it was used for the rapid degradation of p-chlorophenol (4-CP). During the degradation process, Fe0 was able to rapidly replenish the constantly depleted Fe2+ in the reaction system and brought in a large number of additional electrons. The ineffective decomposition of H2O2 due to the use of H2O2 as an electron donor in the reduction reactions from Fe3+ to Fe2+ and from Mn3+ to Mn2+ was avoided. Finally, based on the experimental results of LC-MS and combined with theoretical calculations, the degradation process of 4-CP was rationally analyzed, in which the intermediates were mainly p-chloro-catechol, p-chloro resorcinol, and p-benzoquinone. Fe0@FeMn-NC nano-enzymes have excellent catalytic activity as well as structural stability and perform well in the treatment of simulated wastewater containing a variety of phenolic pollutants as well as real chemical wastewater. It provides some insights and methods for the application of peroxidase-like enzymes in the degradation of organic pollutants.

Partially oxidized mackinawite/biochar for photo-Fenton organic contaminant removal: Synergistically improve interfacial electron transfer and H2O2 activation.

Immobilizing Fe-based nanoparticles on electron-rich biochar has becoming an attractive heterogeneous Fenton-like catalysts (Fe/BC) for wastewater decontamination. However, the insufficient graphitization of biochar causing low electron transfer and by slow H2O2 activation limited its application. Herein, we firstly constructed FeS/biochar composite through all-solid molten salt method (Fe/MSBCs), which can provide strong polarization force and liquid reaction environment to improve carbonization. As expected, the obtained Fe/MSBCs exhibits high surface area and fast interfacial electron transfer between FeS and biochar. More importantly, the partially oxidized FeS (001) facet facilitate H2O2 adsorption and thermodynamically easily decomposition into •OH. Such a synergistic effect endowed them excellent photo-Fenton degradation performance for methyl orange (MO) with large kinetic rate constants (0.079 min-1) and high H2O2 utilization efficiency (95.9%). This study first demonstrated the critical regulatory role of molten salt method in iron-based biochar composites, which provide an alternative for H2O2 activator in water pollutant control.

Removal of bisphenol A in a heterogeneous Fenton system via biochar synthesized using different Fe precursors: Properties, effects, and mechanisms.

The reactivity and mechanism of the Fe-doped biochar (FeBC) Fenton reaction are typically influenced by the amount and type of Fe species in materials. This study investigated the effects of different Fe precursors (FeSO4, Fe(NO)3, FeCl2, and FeCl3) used to prepare Fenton catalyst FeBCs (FeSBC, FeNBC, FeC2BC, and FeC3BC) on the physicochemical characteristics, pH resistance, and reactivity for bisphenol A (BPA) removal. In addition to the FeSBC/H2O2 (0.007 min-1) system, FeNBC/H2O2 (1.143 min-1), FeC2BC/H2O2 (0.278 min-1), and FeC3BC/H2O2 (0.556 min-1) completely removed BPA within 20 min under the optimal conditions (FeBCs: 0.1 g/L; H2O2: 1 mM; BPA: 20 mg/L; pH 3). FeBCs/H2O2 systems demonstrated good stability and resistance to inorganic anions and natural organic matter under appropriate initial pH conditions. However, FeC2BC and FeC3BC exhibited better pH applicability than FeNBC. Characterization results indicated that the physicochemical properties of FeBCs were dependent on the Fe precursor, which correlated with the degree of Fe corrosion and the production of distinct reactive oxygen species (ROS). Quenching experiments and electron spin resonance detection results indicated that OH, 1O2, and O2- species were all engaged in BPA removal; the ROS concentrations were significantly influenced by the initial pH and Fe precursor. The results indicate that Fe precursors significantly impact the performance and characteristics of Fe-based biochar materials, which are tailorable to specific applications.

Sulfur doping-induced morphological and electronic structure modification of polyoxometalate FeWO4 for enhanced removal of organic pollutants from water.

Wolframite (FeWO4), a typical polyoxometalate, serves as an auspicious candidate for heterogeneous catalysts, courtesy of its high chemical stability and electronic properties. However, the electron-deficient surface-active Fe species in FeWO4 are insufficient to cleave H2O2 via Fe redox-mediated Fenton-like catalytic reaction. Herein, we doped Sulfur (S) atom into FeWO4 catalysts to refine the electronic structure of FeWO4 for H2O2 activation and sulfamethoxazole (SMX) degradation. Furthermore, spin-state reconstruction on S-doped FeWO4 was found to effectively refine the electronic structure of Fe in the d orbital, thereby enhancing H2O2 activation. S doping also accelerated electron transfer during the conversion of sulfur species, promoting the cycling of Fe(III) to Fe(II). Consequently, S-doped FeWO4 bolstered the Fenton-like reaction by nearly two orders of magnitude compared to FeWO4. Significantly, the developed S-doped FeWO4 exhibited a remarkable removal efficiency of approximately 100% for SMX within 40 min in real water samples. This underscores its extensive pH adaptability, robust catalytic stability, and leaching resistance. The matrix effects of water constituents on the performance of S-doped FeWO4 were also investigated, and the results showed that a certain amount of Cl-, SO42-, NO3-, HCO3- and PO43- exhibited negligible effects on the degradation of SMX. Theoretical calculations corroborate that the distinctive spin-state reconstruction of Fe center in S-doped FeWO4 is advantageous for H2O2 decomposition. This discovery offers novel mechanistic insight into the enhanced catalytic activity of S doping in Fenton-like reactions and paves the way for expanding the application of FeWO4 in wastewater treatment.

Electron cycling mechanism in Fe/Mn DSAzyme accelerates BPA degradation and nanoenzyme regeneration.

Peroxidase-like (POD-like) as a kind of new Fenton-like catalyst can effectively activate H2O2 to degrade organic pollutants in water, but improving the catalytic activity and stability of POD-like remains a challenging task. Here, we synthesized a novel dual single-atom nanoenzyme (DSAzyme) FeMn/N-CNTs with Fe-N4 and Mn-N4 bimetallic single-atom active centers by mimicking the active centers of natural enzymes and taking advantage of the synergistic effect between the dual metals. FeMn/N-CNTs DSAzyme showed significantly enhanced POD-like activity compared to monometallic-loaded Fe/N-CNTs and Mn/N-CNTs. Within the FeMn/N-CNTs/H2O2 system, bisphenol A (BPA) could be removed 100 % within 20 min. DFT calculations show that Mn-N4 in FeMn/N-CNTs can readily adsorb negatively charged BPA molecules and capture electrons. Meanwhile, Fe-N4 sites can easily adsorb H2O2 molecules, leading to their activation and splitting into strongly oxidizing hydroxyl radicals (·OH). Throughout this process, electrons are continuously recycled in BPA → Mn-N4 → Fe-N4 → H2O2, effectively promoting the regeneration of Fe2+. Practical studies on wastewater and cycling experiments have demonstrated the great potential of this method for remediating water environments.

H2 O2 -Inducible DNA Cross-linking Agents Capable of Releasing Multiple DNA Alkylators as Anticancer Prodrugs.

Three compounds with arylboronate esters conjugated with two equivalent nitrogen mustards [bis(2-chloroethyl)methylamine, HN2] have been synthesized and characterized. These inactive small molecules selectively react with H2 O2 to produce multiple DNA cross-linkers, such as two HN2 molecules alongside a bisquinone methide (bisQM), leading to efficient DNA ICL formation. In comparison to other amine functional groups, using HN2 as a leaving group greatly improves the DNA cross-linking efficiency of these arylboronate esters as well as cellular activity. The introduction of HN2 in these arylboronate ester analogues favored the generation of bisQM that can directly cross-link DNA. Two equivalents of HN2 are also generated from these compounds upon treatment with H2 O2 , which directly produces DNA ICL products. The cumulative effects of HN2 and bisQM on DNA cross-linking makes these molecules highly effective H2 O2 -inducible DNA ICL agents. The three compounds with HN2 as a leaving group showed greatly enhanced cytotoxicity towards cancer cells in comparison to those containing trimethyl amine as a leaving group. This provides an effective strategy for further design of novel potential ROS-activated anticancer prodrugs.

A Nano-Autophagy Inhibitor Triggering Reciprocal Feedback Control of Cholesterol Depletion for Solid Tumor Therapy.

Solid tumors are characterized by enhanced metabolism of lipid, particularly cholesterol, inspiring the exploration of metabolic therapy through cholesterol oxidase (COD)-mediated cholesterol deprivation. However, the therapeutic efficacy of COD is limited due to the hypoxic tumor microenvironment and the protective autophagy triggered by cholesterol deprivation. Herein, a combination therapy for metabolically treating solid tumors through COD in conjunction with molybdenum oxide nanodots (MONDs), which serve as both potent oxygen generators and autophagy inhibitors, is reported. MONDs convert H2 O2 (arising from COD-mediated cholesterol oxidation) into O2 , which is then recycled by COD to form reciprocal feedback for cholesterol depletion. Concurrently, MONDs can overcome autophagy-induced therapeutic resistance frequently occurring in conventional nutrient deprivation therapy by activating AKT/mTOR pathway phosphorylation. Combination therapy in the xenograft model results in an ≈5-fold increase in therapeutic efficiency as compared with COD treatment alone. This functionally cooperative metabolic coupling strategy holds great promise as a novel polytherapy approach that will benefit patients with solid tumors.

Construction of a novel ferrihydrite/MoS2 heterogeneous Fenton-like catalyst for efficient degradation of organic pollutants under neutral conditions.

In this work, we have fabricated a novel Fenton-like ferrihydrite/MoS2 (Fh/MoS2) composite and verified that the introduction of a small amount of iron on the surface of MoS2 can directly promote the exposure of Mo4+, finally enhancing the catalytic activity of the catalyst. Even though the content of iron element is only 1.19% in the composite, the reaction rate constant of Fh/MoS2 system for the degradation of environmental pollutants, such as organic dyes, antibiotic, and ionic liquid, is all much better than that of pure MoS2 system, which is attributed to much more generation of reactive oxygen species derived from synergistic effect of Fe3+/Fe2+ and Mo4+/Mo6+ redox cycles. The results of XPS and low-temperature EPR confirm that the exposure amount of Mo4+ active sites of 10% Fh/MoS2 is greatly increased, which is conducive to the conversion of Fe3+ to Fe2+ in the reaction process, thus effectively promoting the activation of H2O2.