Metallic Active Sites on MoO2(110) Surface to Catalyze Advanced Oxidation Processes for Efficient Pollutant Removal

Recent advances in catalyst design, performance, and challenges of metal-heteroatom-co-doped biochar as peroxymonosulfate activator for environmental remediation

The escalation of global water pollution due to emerging pollutants has gained significant attention. To address this issue, catalytic peroxymonosulfate (PMS) activation technology has emerged as a promising treatment approach for effectively decontaminating a wide range of pollutants. Recently, modified biochar has become an increasingly attractive as PMS activator. Metal-heteroatom-co-doped biochar (MH-BC) has emerged as a promising catalyst that can provide enhanced performance over heteroatom-doped and metal-doped biochar due to the synergism between metal and heteroatom in promoting PMS activation. Therefore, this review aims to discuss the fabrication pathways (i.e., internal vs external doping and pre-vs post-modification) and key parameters (i.e., source of precursors, synthesis methods, and synthesis conditions) affecting the performance of MH-BC as PMS activator. Subsequently, an overview of all the possible PMS activation pathways by MH-BC is provided. Subsequently, Also, the detection, identification, and quantification of several reactive species (such as, •OH, SO4•-, O2•-, 1O2, and high valent oxo species) generated in the catalytic PMS system by MH-BC are also evaluated. Lastly, the underlying challenges associated with poor stability, the lack of understanding regarding the interaction between metal and heteroatom during PMS activation and quantification of radicals in multi-ROS system are also deliberated.

Iron-decorated covalent organic framework as efficient catalyst for activating peroxydisulfate to degrade 2,4-dichlorophenol: Performance and mechanism insight

Herein, a novel two-dimensional double-pore covalent organic framework (JLNU-305) was synthesized using N,N,N',N'-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TAPD) and 2,2'-bipyridine-5,5'-dicarboxaldehyde (BPDA). The extended π-π conjugated structure and nitrogen-riched pyridine in JLNU-305 (JLNU = Jilin Normal University) provide abundant binding sites for Fe doping. The obtained JLNU-305-Fe exhibited high and recycled catalytic efficiency for peroxydisulfate (PDS) activation to completely degrade 10 mg/L 2,4-dichlorophenol (2,4-DCP) within 8 min. The JLNU-305-Fe/PDS system showed excellent catalytic activity and cyclic stability. The capture experiments and electron paramagnetic resonance (ESR) analysis indicated that the catalytic behavior of JLNU-305-Fe/PDS is contributed to the synergistic effect between free radicals and non-free radicals. It is the first time to activate PDS for covalent organic frameworks (COFs) being used to degrade 2,4-DCP, which has a great potential for development and practical application in related water environment remediation.

Defect-Driven Efficient Selective CO2 Hydrogenation with Mo-Based Clusters

Synthetic fuels produced from CO2 show promise in combating climate change. The reverse water gas shift (RWGS) reaction is the key to opening the CO2 molecule, and CO serves as a versatile intermediate for creating various hydrocarbons. Mo-based catalysts are of great interest for RWGS reactions featured for their stability and strong metal-oxygen interactions. Our study identified Mo defects as the intrinsic origin of the high activity of cluster Mo2C for CO2-selective hydrogenation. Specifically, we found that defected Mo2C clusters supported on nitrogen-doped graphene exhibited exceptional catalytic performance, attaining a reaction rate of 6.3 gCO/gcat/h at 400 °C with over 99% CO selectivity and good stability. Such a catalyst outperformed other Mo-based catalysts and noble metal-based catalysts in terms of facile dissociation of CO2, highly selective hydrogenation, and nonbarrier liberation of CO. Our study revealed that as a potential descriptor, the atomic magnetism linearly correlates to the liberation capacity of CO, and Mo defects facilitated product desorption by reducing the magnetization of the adsorption site. On the other hand, the defects were effective in neutralizing the negative charges of surface hydrogen, which is crucial for selective hydrogenation. Finally, we have successfully demonstrated that the combination of a carbon support and the carbonization process synergistically serves as a feasible strategy for creating rich Mo defects, and biochar can be a low-cost alternative option for large-scale applications.

Oxygen vacancies-dominated reactive species generation from peroxymonosulfate activated by MoO3-x for pollutant degradation

Interface oxygen vacancies (OVs) are commonly used to improve the catalytic performance of activators in persulfate-based advanced oxidation processes, but the underlying mechanism was not fully explored. This work reports a facile heat treatment method to regulate OVs in MoO_3-x to elucidate the mechanism of peroxymonosulfate (PMS) activated by OVs to degrade 2,4,4-Trichlorobiphenyl (PCB28). Electron spin resonance, free radical quenching, X-ray photoelectron spectroscopy, and Raman spectroscopy confirmed that both reducing Mo species and OVs of MoO_3-x surface were responsible for PMS activation. Further experiments and Density Function Theory (DFT) calculation suggest that OVs in MoO_3-x induced the formation of superoxide radical (O₂^•-), and then O₂^•- was transformed into singlet oxygen (¹O₂) or mediated PMS activation to generate radicals, which contritbued to 70.2% of PCB28 degradation. The steady-state concentrations of free radical calculated with the kinetics model show that OVs were more favorable to mediate PMS to generate hydroxyl radicals (^•OH) under oxic conditions, while reducing Mo species would like to induce PMS to produce sulfate radicals (SO₄^•-). Overall, this study is dedicated to a new insight into the in-depth mechanism of PMS activation by OVs-rich catalysts and provides a novel strategy for reactive species regulation in PMS based oxidation process.

Efficient hydrogen production from wastewater remediation by piezoelectricity coupling advanced oxidation processes

Efficient H₂ harvesting from wastewater instead of pure water can minimize fresh water consumption, which is expected to solve the problem of water shortage in H₂ production process and contribute to carbon neutrality in the environmental remediation, but the inevitable electron depletion caused by electron-consuming pollutants will result in an exhausted H₂ evolution reaction (HER) performance. In this paper, by coupling piezocatalysis and advanced oxidation processes (AOPs) by a MoS₂/Fe⁰/peroxymonosulfate (PMS) ternary system, extensive types of wastewater achieved considerable H₂ generation, which exceeded the yield in pure water with synchronous advanced degradation of organic pollutants. In addition, profiting from the crucial bridging role of PMS, the H₂ yield in nitrobenzene wastewater after the introduction of PMS-based AOPs increased 3.37-fold from 267.7 μmol·g^-1·h^-1 to 901.0 μmol·g^-1·h^-1 because the presence of PMS both thermodynamically benefited MoS₂ piezocatalytic H₂ evolution and eliminated the electron depletion caused by organic pollutants. By this way, the original repressed H₂ evolution performance in substrate of wastewater not only was regained but even showed a significant enhancement than that in pure water (505.7 μmol·g^-1·h^-1). Additionally, the cyclonic piezoelectric reactor was preliminarily designed for future industrialization. This strategy provided a valuable path for the recycling of actual wastewater by fuel production and synchronous advanced treatment.

Selective Electrochemical Hydrogenation of Phenol with Earth-abundant Ni-MoO2 Heterostructured Catalysts: Effect of Oxygen Vacancy on Product Selectivity

Herein, we report highly efficient carbon supported Ni-MoO₂ heterostructured catalysts for the electrochemical hydrogenation (ECH) of phenol in 0.10 M aqueous sulfuric acid (pH 0.7) at 60 °C. Highest yields for cyclohexanol and cyclohexanone of 95 % and 86 % with faradaic efficiencies of ∼50 % are obtained with catalysts bearing high and low densities of oxygen vacancy (O_v ) sites, respectively. In situ diffuse reflectance infrared spectroscopy and density functional theory calculations reveal that the enhanced phenol adsorption strength is responsible for the superior catalytic efficiency. Furthermore, 1-cyclohexene-1-ol is an important intermediate. Its hydrogenation route and hence the final product are affected by the O_v density. This work opens a promising avenue to the rational design of advanced electrocatalysts for the upgrading of phenolic compounds.

Applications of Spent Lithium Battery Electrode Materials in Catalytic Decontamination: A Review

For a large amount of spent lithium battery electrode materials (SLBEMs), direct recycling by traditional hydrometallurgy or pyrometallurgy technologies suffers from high cost and low efficiency and even serious secondary pollution. Therefore, aiming to maximize the benefits of both environmental protection and e-waste resource recovery, the applications of SLBEM containing redox-active transition metals (e.g., Ni, Co, Mn, and Fe) for catalytic decontamination before disposal and recycling has attracted extensive attention. More importantly, the positive effects of innate structural advantages (defects, oxygen vacancies, and metal vacancies) in SLBEMs on catalytic decontamination have gradually been unveiled. This review summarizes the pretreatment and utilization methods to achieve excellent catalytic performance of SLBEMs, the key factors (pH, reaction temperature, coexisting anions, and catalyst dosage) affecting the catalytic activity of SLBEM, the potential application and the outstanding characteristics (detection, reinforcement approaches, and effects of innate structural advantages) of SLBEMs in pollution treatment, and possible reaction mechanisms. In addition, this review proposes the possible problems of SLBEMs in practical decontamination and the future outlook, which can help to provide a broader reference for researchers to better promote the implementation of “treating waste to waste” strategy.

Enhanced activation of peroxymonosulfate by a floating FeMo3Ox/C3N4 photocatalyst under visible-light assistance for oxytetracycline degradation: Performance, mechanisms and comparison with H2O2 activation

In this study, a floating FeMo₃O_x/C₃N₄-EP (FM-C-P) composite with highly stability and reusability was synthesized by an impregnation/calcination process and used to activate peroxymonosulfate (PMS) for oxytetracycline (OTC) degradation under visible light irradiation. The results demonstrated that 98.1% of OTC (50 mg/L) removal can be achieved by the activation of PMS (5 mM) using FM-C-P (1 g/L) in 30 min under visible light irradiation. The pseudo-first-order rate constant was calculated to be 0.181 min^-1. The degradation process with PMS was hardly affected by pH (3-11) and co-existing substance. ·SO₄^-, ·OH, ·O₂^- and ¹O₂ were produced in the Vis/PMS/FM-C-P system and ¹O₂ was determined to be the main reactive oxygen species (ROSs). The high efficiency of ROSs production mainly contributed to two mechanisms. Firstly, via the combination of ≡Fe (II)-·SO₅^- and free state ·SO₅^-, ¹O₂ could be generated on the Fe-N_x site. Secondly, photo-induced electrons in the FeMo₃O_x/g-C₃N₄ heterojunction could react with Fe (III) and Mo (VI) to form catalytically active species Fe (II) and Mo (IV). Moreover, the proposed degradation pathway and the toxicity of intermediated products was analyzed. Overall, this study was expected to deepen the understanding of the photo-assisted PMS activation and the generation of ¹O₂ with the presence of metal-oxide/C₃N₄ heterojunction.

Spent LiFePO4: An old but vigorous peroxymonosulfate activator for degradation of organic pollutants in water

Iron-based catalysts have been demonstrated to activate peroxymonosulfate (PMS) to generate reactive radicals, which is however limited by their complex preparation process, high costs and inefficiency for practical applications. Herein we obtain spent LiFePO₄ (SLFP), with powerful catalytic capacity by a simple one-step treatment of the retired LiFePO₄ cathode material, for PMS activation to decontaminate organic pollutants. Lithium defects and oxygen vacancies in SLFP play critical roles for PMS utilization, further confirmed by density functional theory (DFT) calculations. SLFP materials rapidly adsorb PMS, and the surface PMS is activated by Fe(II) to generate radicals, with ^•OH playing a major role for the degradation of organics after multi-step reactions. The SLFP/PMS process is finally validated for ability to remove organic contaminants and potential environmental application.

Effective peroxymonosulfate activation by natural molybdenite for enhanced atrazine degradation: Role of sulfur vacancy, degradation pathways and mechanism

In this study, natural molybdenite (MoS₂) was applied to activate peroxymonosulfate (PMS) for the removal of atrazine (ATZ) and its degradation mechanism was investigated. Molybdenite exhibits superior catalytic performance. The best condition for atrazine degradation efficiency (>99%) was obtained with molybdenite concentration of 0.4 g/L, PMS concentration of 0.1 mM, and ATZ concentration of 12 μM within 10 min under experimental conditions. Electron paramagnetic resonance (EPR) test and chemical probe test further proved that HO^• and SO₄^•- played important roles in the molybdenite/PMS system, and SO₄^•- was dominant. Meanwhile, Electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) tests showed that sulfur vacancies and edge sulfur played important roles in the system. Edge sulfur was conducive to Mo⁴⁺ exposure, while sulfur vacancy facilitated electron transfer and reduced Mo⁶⁺ back to Mo⁴⁺. Combined with DFT calculation, the role of sulfur in the degradation process was verified. Besides, five ATZ degradation pathways were proposed. Finally, the degradation ability of the molybdenite/PMS system for different pollutants and in actual water bodies was also explored. This work provided ideas for exploring the degradation of organic contaminants by natural minerals.

Heterogeneous Activation of Peroxymonosulfate by a Spinel CoAl2O4 Catalyst for the Degradation of Organic Pollutants

Bimetallic catalysts have significantly contributed to the chemical community, especially in environmental science. In this work, a CoAl2O4 spinel bimetal oxide was synthesized by a facile co-precipitation method and used for the degradation of organic pollutants through peroxymonosulfate (PMS) activation. Compared with Co3O4, the as-prepared CoAl2O4 possesses a higher specific surface area and a larger pore volume, which contributes to its becoming increasingly conducive to the degradation of organic pollutants. Under optimal conditions (calcination temperature: 500 °C, catalyst: 0.1 g/L, and PMS: 0.1 g/L), the as-prepared CoAl2O4 catalyst could degrade over 99% of rhodamine B (RhB) at a degradation rate of 0.048 min−1, which is 2.18 times faster than Co3O4 (0.022 min−1). The presence of Cl− could enhance RhB degradation in the CoAl2O4/PMS system, while HCO3− and CO32− inhibit RhB degradation. Furthermore, the considerable reusability and universality of CoAl2O4 were testified. Through quenching tests, 1O2 and SO4•− were identified as the primary reactive species in RhB degradation. The toxicity evaluation verified that the degraded solution exhibited lower biological toxicity than the initial RhB solution. This study provides new prospects in the design of cost-effective and stable cobalt-based catalysts and promotes the application of PMS-based advanced oxidation processes for refractory wastewater treatment.

Effective removal of organics from Bayer liquor through combined sonolysis and ozonation: Kinetics and mechanism

The presence of organic compounds in the waste liquor is of serious environmental concern that has plagued the development of alumina industry (Bayer Process). The present work attempts to develop a green and efficient process for removal of organics utilizing combined effect of sonolysis and ozonation (US/O₃). The effects of reaction duration, ozone concentration and ultrasonic power are assessed for sonolysis (US), ozonation (O₃) and combination of sonolysis and ozonation (US/O₃). The optimal conditions for US/O₃ treatment system is identified to be a reaction duration of 7 h, ozone concentration of 7.65 g/h, and ultrasonic power of 600 W. The total organic carbon (TOC) removal and decolorization are 60.13% and 87.1%, respectively. The process can be scaled-up to industrial scale, which could potentially serve to be a convenient, safe and sustainable alternative to the exisiting treatment technologies. Additionally, the treated waste water can be reused contributing to an improvement in the overall economics.

A comprehensive review on persulfate activation treatment of wastewater

With increasingly serious environmental pollution and the production of various wastewater, water pollutants have posed a serious threat to human health and the ecological environment. The advanced oxidation process (AOP), represented by the persulfate (PS) oxidation process, has attracted increasing attention because of its economic, practical, safety and stability characteristics, opening up new ideas in the fields of wastewater treatment and environmental protection. However, PS does not easily react with organic pollutants and usually needs to be activated to produce oxidizing active substances such as sulfate radicals (SO₄^-) and hydroxyl radicals (OH) to degrade them. This paper summarizes the research progress of PS activation methods in the field of wastewater treatment, such as physical activation (e.g., thermal, ultrasonic, hydrodynamic cavitation, electromagnetic radiation activation and discharge plasma), chemical activation (e.g., alkaline, electrochemistry and catalyst) and the combination of the different methods, putting forward the advantages, disadvantages and influencing factors of various activation methods, discussing the possible activation mechanisms, and pointing out future development directions.

Designing NAZO@BC electrodes for enhanced elimination of hydrophilic organic pollutants in heterogeneous electro-Fenton system: Insights into the detoxification mediated by 1O2 and •OH

Hydrophilic organic pollutants (HLOPs) in effluents of wastewater treatment plants are more prevalent than hydrophobic counterparts, therefore development of upstream processes that can effectively enhance the removal of HLOPs can substantially enhance overall treatment performance. To bridge this gap, 3D electrodes made of biochar-supported Al-ZnO nanoparticles (NAZO@BC) applied in heterogeneous electro-Fenton (EF) system, abbreviated as NBE-EF system, is rationally designed for enhanced elimination of HLOPs in wastewater. Our analysis indicates the NBE-EF system results in an efficient THM elimination, 42.4 times greater than that of conventional EF system. MoS₂ as an efficient cocatalyst plays an important role in the conversion from Fe(III) to Fe(II). Singlet oxygen (¹O₂) and hydroxyl radical (•OH) are identified as the primary reactive oxygen species (ROS) in the NBE-EF system. NAZO@BC electrodes could concentrate HLOPs on their surface and degrade it effectively, achieving also a self-cleaning effect. Effective elimination of four HLOPs, i.e., thiamethoxam (THM), dinotefuran (DIN), nitenpyram (NIT), and acetamiprid (ACE), demonstrated the high degradation performance of the NBE-EF system, even at neutral and alkaline conditions. This study provides a new approach for enhanced elimination of HLOPs in wastewater treatment and mechanical insights into degradation pathways and toxicity attenuation.

Interface Engineering of Co(OH)2 Nanosheets Growing on the KNbO3 Perovskite Based on Electronic Structure Modulation for Enhanced Peroxymonosulfate Activation

Material-enhanced heterogonous peroxymonosulfate (PMS) activation on emerging organic pollutant degradation has attracted intensive attention, and a challenge is the electron transfer efficiency from material to PMS for radical production. Herein, an interface architecture of Co(OH)₂ nanosheets growing on the KNbO₃ perovskite [Co(OH)₂/KNbO₃] was developed, which showed high catalytic activity in PMS activation. A high reaction rate constant (k₁) of 0.631 min^-1 and complete removal of pazufloxacin within 5 min were achieved. X-ray photoelectron spectroscopy, X-ray absorption near edge structure spectra, and density functional theory (DFT) calculations revealed the successful construction of the material interface and modulated electronic structure for Co(OH)₂/KNbO₃, resulting in the hole accumulation on Co(OH)₂ and electron accumulation on KNbO₃. Bader topological analysis on charge density distribution further indicates that the occupations of Co-3d and O-2p orbitals in Co(OH)₂/KNbO₃ are pushed above the Fermi level to form antibonding states (σ*), leading to high chemisorption affinity to PMS. In addition, more reactive Co(II) with the closer d-band center to the Fermi level results in higher electron transfer efficiency and lower decomposition energy of PMS to SO₄^•-. Moreover, the reactive sites of pazufloxacin for SO₄^•- attack were precisely identified based on DFT calculation on the Fukui index. The pazufloxacin pathways proceeded as decarboxylation, nitroheterocyclic ring opening reaction, defluorination, and hydroxylation. This work can provide a potential route in developing advanced catalysts based on manipulation of the interface and electronic structure for enhanced Fenton-like reaction such as PMS activation.

Peroxymonosulfate (PMS) activation by mackinawite for the degradation of organic pollutants: Underappreciated role of dissolved sulfur derivatives

The internal Fe²⁺/Fe³⁺ cycle is important for peroxymonosulfate (PMS) activation by iron-based materials to produce the reactive oxidative species (ROS) for the breakdown of organic contaminants. Previous studies have focused on the contribution of heterogeneous sulfur species to the Fe²⁺/Fe³⁺ cycle such as lattice S(-II) and surface SO₃^2- of iron sulfides. In this study, we found that the dissolved S(-II) from mackinawite (FeS) had a substantial contribution to the Fe²⁺/Fe³⁺ cycle. Furthermore, the oxidation intermediates of the dissolved S(-II) such as S₂O₃^2- and SO₃^2- ions could convert Fe³⁺ to Fe²⁺ in solution. The elimination of target organic pollutant bisphenol A (BPA) derived from PMS activation triggered by the dissolved Fe²⁺ might be enhanced by the equivalent dissolved S(-II) in the FeS/PMS system. These results revealed that previous studies underestimated the significance of PMS activation by dissolved Fe²⁺ of iron sulfides to organic pollutant degradation. Moreover, SO₄^•- and •OH were more likely to be the main ROS for BPA degradation in the FeS/PMS system compared with FeO²⁺. Considering that the metal sulfides have been widely used to activate PMS, H₂O₂ and peroxydisulfate, this study offers a new perspective on the function of sulfur in these advanced oxidation processes.

Self-assembly of MoS2 nanosheet adhered on Fe-MOF heterocrystals for peroxymonosulfate activation via interfacial interaction

A novel heterogeneous catalyst PB@MoS₂ was successfully synthesized via facile hydrothermal processes and identified as a superior peroxymonosulfate (PMS) activator for organic pollutants degradation under visible light irradiation. The MoS₂ nanosheet is uniformly adhered to the surface of iron-based metal-organic framework Prussian blue (PB) cube, exhibiting a tightly hydrangeas-like structure. Benefiting from strongly interfacial interaction (FeMo-sulfide) between PB and MoS₂, as confirmed by ⁵⁷Fe M̈össbauer spectra and electrochemical measurement, the PB@MoS₂ catalyst significantly accelerate the charge carrier transfer via interfacial FeMo-sulfide and thereby improve PMS activation ability to generate abundant reactive radicals. Moreover, the crucial iron active site was steadily validated by introduction of sodium oxalate trapping agent and visible light. In summary, the visible light induced Fenton-like reaction over PB@MoS₂ catalyst promoted the Fe^II/Fe^III cycling and electron transport and further triggered the reactive species (SO₄^-, OH, O₂^- and h⁺) productivity, realizing an extraordinarily high degradation and mineralization efficiency for various refractory organic pollutants. This work would provide a deep insight into develop heterogeneous Fe-based metal organic framework/MoS₂ catalyst for environmental restoration and remediation by photo-Fenton reaction.

In situ grown bacterial cellulose/MoS2 composites for multi-contaminant wastewater treatment and bacteria inactivation

For the purpose of developing multifunctional water purification materials capable of degrading organic pollutants while simultaneously inactivating microorganisms from contaminated wastewater streams, we report here a facile and eco-friendly method to immobilize molybdenum disulfide into bacterial cellulose via a one-step in-situ biosynthetic method. The resultant nanocomposite, termed BC/MoS₂, was shown to possess a photocatalytic activity capable of generating •OH from H₂O₂, while also exhibiting photodynamic/photothermal mechanisms, the combination of which exhibits synergistic activity for the degradation of pollutants as well as for bacterial inactivation. In the presence of H₂O₂, the BC/MoS₂ nanocomposite exhibited excellent antibacterial efficacy upwards of 99.9999% (6 log units) for the photoinactivation of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus upon infrared (IR) lamp illumination (100 W, 760 nm ≤ λ ≤ 5000 nm, 15 cm vertical distance; 5 min). Mechanistic studies revealed synergistic pathogen inactivation resulting from the combination of photocatalytically generated •OH and hyperthermia induced by the photothermal conversion of the near-IR light. In addition, the BC/MoS₂ nanocomposite also showed excellent photodegradation activity for common aqueous contaminants in the presence of H₂O₂, including malachite green (a textile dye), catechol violet (a phenol) and formaldehyde. Taken together, our findings demonstrate that sustainable materials such as BC/MoS₂ have potential applications in wastewater treatment and microorganism disinfection.

Mo2C/C catalyst as efficient peroxymonosulfate activator for carbamazepine degradation

Compared with generally reported Mo⁴⁺/Mo⁶⁺ redox cycle, the exposed Mo²⁺ active sites of Mo-based materials may have a superior potential to effectively activate PMS. However, Mo²⁺-involved materials as efficient catalysts in sulfate radical-based advanced oxidation processes (SR-AOPs) has rarely been researched. In this work, a spherical Mo₂C-loaded carbon material, Mo₂C/C, was prepared for the first time by hydrothermal-calcination method directly used as peroxymonosulfate (PMS) activator towards carbamazepine (CBZ) degradation. The results showed that the Mo₂C/C could effectively remove nearly 100% CBZ (5 mg·L^-1) in the presence of 0.75 mM PMS within 75 min under the optimal conditions. It was attributed to the reductive Mo²⁺, as active sites, benefits to absorb PMS on the surface to trigger electron transmission, and the defective carbon structures accelerate the activation of PMS. Consequently, the efficient Mo²⁺/Mo⁴⁺/Mo⁶⁺ electron transfer was achieved, resulting in excellent catalysis. A series of reactive species including SO₄^-, OH and ¹O₂ species participated in CBZ oxidation degradation. Derived from the superior stability and reusability of Mo₂C/C, the removal rate of CBZ still maintained above 80% even after five consecutive cycles, which is expected to be applied in the wastewater treatment including pharmaceuticals in the future.

Ultra-efficient catalytic degradation of malachite green dye wastewater by KMnO4-modified biochar (Mn/SRBC)

In this work, KMnO₄-modified biochar was prepared from spirulina residue as the research object. Herein, we report the synthesis, characterization, and catalytic degradation performance of KMnO₄-modified biochar, given that heterogeneous catalytic oxidation is an effective way to treat dye wastewater rapidly. The Mn/SRBC catalyst prepared by KMnO₄ modification was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption and laser Raman spectroscopy. In addition, we compared the results with that of the unmodified SRBC. The results showed that the Mn/SRBC catalyst prepared by KMnO₄ modification had a rich pore structure, which provided sufficient contact area for the catalytic reaction. In the presence of H₂O₂, the catalyst could be used to catalyze the oxidative degradation of malachite green in aqueous solution with ultra-high efficiency. In the experiment, the initial pH values of the reaction system had a significant influence on the reaction rate. The removal effect of biochar on the malachite green was poor in an alkaline environment. Within a specific range, the removal rate of malachite green was proportional to the concentration of H₂O₂ in the reaction system. The degradation rate of malachite green dye at 8000 mg L⁻¹ was about 99% in the presence of the catalyst over 5 mmol L⁻¹ hydrogen peroxide for 30 min. These results show the potential application of algae residue biochar and carbon-based composite catalysts for degrading and removing dye wastewater.

In this work, KMnO₄-modified biochar was prepared from spirulina residue as the research object.

Crucial roles of 3D-MoO2-PBC cocatalytic electrodes in the enhanced degradation of imidacloprid in heterogeneous electro-Fenton system: Degradation mechanisms and toxicity attenuation

Imidacloprid (IMI), as the most-consumed pesticide, has posed a severe threat to the water ecosystem due to its recalcitrance and inefficient elimination in the traditional wastewater treatment. Herein, a heterogeneous electro-Fenton (EF) system coupled with 3D-MoO₂-porous biochar (PBC) cocatalytic electrodes, abbreviated as 3D-MPE-EF, is initially applied to promote the elimination of IMI in the agrochemical wastewater from pesticide production. The elimination rate of IMI by 3D-MPE-EF system is 18.15 times higher than that by traditional EF system at pH 7.0. The utilization of 3D-MoO₂-PBC electrodes sufficiently compensates for inherent deficiencies of traditional EF system. The circular utilization of Fe is also addressed by 3D-MoO₂-PBC cocatalytic electrodes to reduce the consumption of Fe²⁺ and the deposition of iron mud. Through comparison, MoO₂ is considered the most appropriate cocatalyst in terms of the reutilization of Fe and degradation of IMI. Eight mechanisms are identified in the degradation pathways of IMI by UPLC-Q-TOF-MS. The ecotoxicities of IMI are remarkably attenuated in the 3D-MPE-EF system. This study provides insights into the roles of 3D-MoO₂-PBC cocatalytic electrodes in the enhanced elimination of IMI in heterogeneous EF system.

Visible-light-driven peroxymonosulfate activation in photo-electrocatalytic system using hollow-structured Pt@CeO2@MoS2 photoanode for the degradation of pharmaceuticals and personal care products

In this study, we constructed an innovative photo-electrocatalysis-assisted peroxymonosulfate (PEC/PMS) system to degrade pharmaceuticals and personal care products (PPCPs). A hollow-structured photoanode (i.e., Pt@CeO₂@MoS₂) was specifically synthesized as a photoanode to activate PMS in the PEC system. As proof of concept, the Pt@CeO₂@MoS₂ photoanode exhibited superior degradation performance toward carbamazepine (CBZ) with PMS assistance. Specifically, the kinetic constant of PEC/PMS (k = 0.13202 min^-1) could be enhanced about 87.4 times compared to that of the PEC system (0.00151 min^-1) alone. The PMS activation mechanism revealed that the synergistic effect between the hollow material and the change of surface valence states (Ce³⁺ to Ce⁴⁺) and (Mo⁴⁺ to Mo⁶⁺) contribute to enhancing the degradation efficiency of the visible-light-driven PEC/PMS process. The scavenger testing and EPR showed that ¹O₂, O₂^•-, SO₄^•- and •OH play dominant roles in the SR-AOPs. Furthermore, the applicability of Pt@CeO₂@MoS₂ used in SR-AOPs was systematically investigated regarding of the reaction parameters and identification of intermediates and dominant radicals as well as the mineralization rate and stability. The outcomes of this study can provide a new platform for environmental remediation.

Constructing an Acidic Microenvironment by MoS2 in Heterogeneous Fenton Reaction for Pollutant Control

Although Fenton or Fenton-like reactions have been widely used in the environment, biology, life science, and other fields, the sharp decrease in their activity under macroneutral conditions is still a large problem. This study reports a MoS₂ cocatalytic heterogeneous Fenton (CoFe₂ O₄ /MoS₂ ) system capable of sustainably degrading organic pollutants, such as phenol, in a macroneutral buffer solution. An acidic microenvironment in the slipping plane of CoFe₂ O₄ is successfully constructed by chemically bonding with MoS₂ . This microenvironment is not affected by the surrounding pH, which ensures the stable circulation of Fe³⁺ /Fe²⁺ on the surface of CoFe₂ O₄ /MoS₂ under neutral or even alkaline conditions. Additionally, CoFe₂ O₄ /MoS₂ always exposes "fresh" active sites for the decomposition of H₂ O₂ and the generation of ¹ O₂ , effectively inhibiting the production of iron sludge and enhancing the remediation of organic pollutants, even in actual wastewater. This work not only experimentally verifies the existence of an acidic microenvironment on the surface of heterogeneous catalysts for the first time, but also eliminates the pH limitation of the Fenton reaction for pollutant remediation, thereby expanding the applicability of Fenton technology.

Cu2+/Cu+ cycle promoted PMS decomposition with the assistance of Mo for the degradation of organic pollutant

The limited production of Cu⁺ in the Cu²⁺/PMS processes constrained its large-scan application for the elimination of organic pollutants. In this study, molybdenum powder (Mo) was applied as the co-catalyst to improve the degradation of 2,4-dichlorophenol (2,4-DCP) in Cu²⁺/PMS system at pH 5.6. By the assistance of Mo, Cu²⁺ was rapidly reduced to Cu⁺ which exhibited super activity for the peroxymonosulfate (PMS) activation. Compared with Cu²⁺/PMS processes, the PMS decomposition rate and 2,4-DCP degradation efficiency respectively increased by 62.1% and 83.6% in the Mo co-catalytic Cu²⁺/PMS system after reaction for 20 min. The degradation of 2,4-DCP was completed via both the free radical and non-radical pathways and the free radicals rather than Cu³⁺ contributed most to the reaction. In contrast to fresh Mo, the ratio of Mo⁴⁺ increased and Mo⁶⁺ decreased in the used Mo powder, due to the oxidation of Mo⁰ by Cu²⁺ and/or ∙OH and the reduction of Mo⁶⁺ by O₂∙^-. Additionally, the coexistence of Cl^- and humic acid with low concentrations showed little effects on the Mo/Cu²⁺/PMS system while HCO₃^- presented an obvious depression for 2,4-DCP degradation. During five cycling runs, all the degradation rates were higher than 92.8%, indicating the good stability of Mo/Cu²⁺/PMS system.

Self-Assembly of Nanosheet-Supported Fe-MOF Heterocrystals as a Reusable Catalyst for Boosting Advanced Oxidation Performance via Radical and Nonradical Pathways

Heterojunction catalysts have drawn increasing interest for the visible light-driven Fenton reaction and bring tremendous opportunities for environmental remediation. Herein, a BiOI/MIL-53(Fe) Z-scheme heterojunction (named BMFe) was synthesized for the first time via a facile strategy. Compared with pristine BiOI and MIL-53(Fe) catalysts, the two-dimensional/three-dimensional (2D/3D) heterojunction catalyst manifested remarkable catalytic performance toward degradation of phenol, bisphenol A, methylene blue, and carbamazepine, which is attributed mainly to the interfacial integration and efficient charge separation. By virtue of coupling at the interface, as confirmed by XPS, ⁵⁷Fe Mössbauer spectroscopy, and DFT calculations, the BMFe catalyst promoted the transfer of electron-hole pairs via Z-scheme and improved the chemical activation of hydrogen peroxide. The subsequent holes, free radicals, and nonradicals can effectively and continuously decompose pollutants, achieving a positive synergistic effect between photocatalysis and Fenton reactions. Simultaneously, the specially designed BiOX(X = Br, Cl)/MIL-53(Fe) and BiOI/Fe-MOFs(MIL-101, MIL-88) heterojunctions also exhibited advanced oxidative capacity for organic pollutants. Given their practical value for industrial applications, BMFe beads (1.0 ± 0.15 mm) synthesized via a blend cross-linking method can significantly advance long-term stability and recyclability. The integration of Fe-based metal-organic frameworks with bismuth oxyhalide semiconductors provides a new perspective on developing heterojunction catalysts for environmental remediation.

Are Free Radicals the Primary Reactive Species in Co(II)-Mediated Activation of Peroxymonosulfate? New Evidence for the Role of the Co(II)-Peroxymonosulfate Complex

The catalytic activation of peroxymonosulfate (PMS) is under intensive investigation with potentials as an alternative advanced oxidation process (AOP) in wastewater treatment. Among all catalysts examined, Co(II) exhibits the highest reactivity for the activation of PMS, following the conventional Fenton-like mechanism, in which free radicals (i.e., sulfate radicals and hydroxyl radicals) are reckoned as the reactive species. Herein, we report that the primary reactive species (PRS) is proposed to be a Co(II)-PMS complex (Co(II)-OOSO₃^-), while free radicals and Co(III) species act as the secondary reactive species (SRS) that play a minor role in the Co(II)/PMS process. This Co(II)-OOSO₃^- exhibits several intriguing properties including ability to conduct both one-electron-transfer and oxygen-atom-transfer reactions with selected molecules, both nucleophilic and electrophilic in nature, and strongly pH-dependent reactivity. This study provides novel insights into the chemical nature of the Co(II)-catalyzed PMS activation process.

Constructing MoS2/Lignin-derived carbon nanocomposites for highly efficient removal of Cr(VI) from aqueous environment

Effective removal of Cr(VI) pollution from aquatic environment is in pressing need because of the detrimental effect of Cr(VI) to human health. Herein, we report a facile two-step approach to synthesis MoS₂/Lignin-derived Carbon (MoS₂@LDC) nanocomposites for highly efficient elimination of Cr(VI) from aqueous solutions. The MoS₂@LDC exhibited outstanding removal efficient for Cr(VI) (198.70 mg/g at pH = 2.0, T = 298.15 K and C_Initial = 20.0 mg/L). 99.35% of Cr(VI) can be removed by the composites in 30 min. Thermodynamic and kinetic studies suggest the removal of Cr(VI) is through both adsorption and reduction. The performance of MoS₂@LDC can be further enhanced by hydrogen plasma treatments, which was attributed to the sulfur vacancies induced improvement in the reduction activity of MoS₂ layer. The results of this work can guide the rational design of high-performance nanocomposite for efficient remediation of heavy metals in aquatic environment.

Emerging Hexagonal Mo2C Nanosheet with (002) Facet Exposure and Cu Incorporation for Peroxymonosulfate Activation Toward Antibiotic Degradation

The catalyst with a special exposed active facet and multivalent element synergism is much desired for advanced oxidation progress (AOP) reaction. Herein, an emerging substrate, Cu-incorporated Mo₂C, with an active (002) facet exposed was developed by one-step calcination to activate peroxymonosulfate (PMS) toward antibiotic degradation. Combining the multivalent Cu-Mo synergistic effect and Cu complexing interaction, Cu was incorporated onto the Mo₂C surface to further enhance its antibiotic removal through PMS activation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements indicated the 5% Cu-Mo₂C exhibited in the hexagonal nanosheet with Cu uniformly dispersed on the surface. Moreover, 5% Cu-Mo₂C displayed excellent PMS activation which could fully degrade the tetracycline (TC) within 20 min, and the degradation rate was found to be at least 20 times higher than those of pure Mo₂C, classical Fe₂O₃ and Co₃O₄, and Fenton reaction of 5% Cu-Mo₂C. The results were found to be ascribed to enhanced electrical conductivity, multivalent Cu-Mo synergism, and increased generation of active radicals which contributed in the sequence SO₄•^- > •OH > O₂^•-. Surface chemical analysis combined with density functional theory (DFT) calculations confirmed that both Cu²⁺/Cu⁺ and Mo⁶⁺/Mo⁴⁺/Mo²⁺ redox cycles occurred on the (002) plane of Mo₂C, which dominated more free electrons and mainly accounted for facilitating PMS activation. Meanwhile, systematically conditional experiments uncovered that the 5% Cu-Mo₂C exhibited superb catalysis even under a wide pH and temperature, various natural polluted waters and coexisting ions, and long-time recycle. In addition, the as-prepared catalyst presented excellent adaptability for the degradation of different organic effluents originated from medical, dyeing, and beneficiation wastewaters. Considering its great performance, stability, and applicability, 5% Cu-Mo₂C would be a capable candidate for PMS activation toward large-scale practical application in environmental remediation.

Molybdenum disulfide nanosheets vertically grown on self-supported titanium dioxide/nitrogen-doped carbon nanofiber film for effective hydrogen peroxide decomposition and "memory catalysis"

A self-supporting catalyst consisting of 1D/2D vertical molybdenum disulfide@titanium dioxide/nitrogen-doped carbon nanofiber (MoS₂@TiO₂/NCNFs) was prepared and tested. It showed efficient hydrogen peroxide (H₂O₂) decomposition to generate hydroxyl radical (OH) and degradation of various pollutants under solar irradiation. The contribution of the increase in MoS₂ edges for decomposing H₂O₂ was 0.0698 min^-1. That is 9.83 times the rate of the original MoS₂ edges resulting from the vertical structure. Specially, the catalyst degraded various aromatic pollutants even in the dark by releasing electrons stored in its graphite component to realize "memory catalysis". Also, it exhibited high degradation efficiency under outdoor solar irradiation. The catalyst was easily separated from the treated water, avoiding complex separation processes. All these features suggest this catalyst has great potential in practical water and sewage treatment applications.

Nano-MoO2 activates peroxymonosulfate for the degradation of PAH derivatives

The rapid and efficient degradation of polycyclic aromatic hydrocarbon (PAH) derivatives with toxicological properties remains a substantial challenge. In this study, a cost-effective and eco-friendly catalyst, nano-MoO₂ (0.05 g L^-1), exhibited excellent performance in activating 4.0 mmol L^-1 peroxymonosulfate (PMS) for the degradation of naphthalene derivatives with 1 mg L^-1 in aqueous systems; these derivatives include 1-methylnaphthalene, 1-nitronaphthalene, 1-chloronaphthalene, 1-naphthylamine and 1-naphthol, with high degradation rates of 87.52%, 86.23%, 97.87%, 99.74%, and 77.16%. Nano-MoO₂ acts as an electron donor by transferring an electron causing O-O bond of PMS to cleave producing SO₄^·-, and later ^·OH. Electron paramagnetic resonance (EPR) analysis combined with free radical quenching research indicated that SO₄^·- and ^·OH dominated the degradation of naphthalene derivatives, and O₂^·- and ¹O₂ participated in the processes. X-ray photoelectron spectroscopy (XPS) revealed the transformation of Mo(IV) to Mo(V) and Mo(VI), which suggested that the activation process proceeded via electron transfer from nano-MoO₂ to PMS. The applicability of the nano-MoO₂/PMS system in influencing parameters and stability was explored. The degradation pathways were primarily elucidated for each naphthalene derivative based on the intermediates identified in the systems. The -CH₃, -NO₂, -Cl, -OH substituents increased the positive electrostatic potential (ESP) on the molecular surface of 1-methylnaphthalene, 1-nitronaphthalene, 1-chloronaphthalene, and 1-naphthol, which reduced the electrophilic reaction and electron transfer between the reactive species and pollutants, leading to a lower degradation rate of naphthalene derivatives than the parent compound. However, the effect of -NH₂ substituents is the opposite. These findings suggest that nano-MoO₂ may aid as a novel catalyst in the future remediation of environments polluted with PAH derivatives.

Recent advances in waste water treatment through transition metal sulfides-based advanced oxidation processes

With the ever-growing water pollution issues, advanced oxidation processes (AOPs) have received growing attention due to their high efficiency in the removal of refractory organic pollutants. Transition metal sulfides (TMSs), with excellent optical, electrical, and catalytical performance, are of great interest as heterogeneous catalysts. These TMSs-based heterogeneous catalysts have been demonstrated to becapable and adaptable in water purification through advanced oxidation processes. The aim of this review is to conduct an exhaustive analysis and summary of recent progress in the application of TMSs-based AOPs for water decontamination. Firstly, the commonly used tuning strategies for TMSs-based catalysts are concisely introduced, including artificial size and shape control, composition control, doping, and heterostructure manufacturing. Then, a comprehensive overview of the current state-of-the-art progress on TMSs-based AOPs (i.e., Fenton-like oxidation, photocatalytic oxidation, and electro chemical oxidation processes) for wastewater treatment is discussed in detail, with an emphasis on their catalytic performance and involved mechanism. In addition, influencing factors of water chemistry, namely, pH, temperature, dissolved oxygen, inorganic species, and natural organic matter on the catalytic performance of established AOPs are analyzed. Furthermore, the reusability and stability of TMSs-based catalysts in these AOPs are also outlined. Finally, current challenges and future perspectives related to TMSs-based catalysts and their applications for AOPs wastewater treatment are proposed. It is expected that this review would shed some light on the future development of TMSs-based AOPs towards water purification.

Three-Dimensional Hierarchical Porous Structures of Metallic Glass/Copper Composite Catalysts by 3D Printing for Efficient Wastewater Treatments

Finding highly efficient and reusable catalysts for advanced oxidation processes is a crucial endeavor to resolve the severe water pollution problems. Although numerous nanocatalysts have been developed in the past few decades, their recyclability along with sustainably high catalytic efficiency still remain challenging. Here, we propose a new strategy for designing efficient and reusable catalysts, that is, introducing Cu as a reductant into a metallic glass-based catalyst and constructing three-dimensional hierarchical porous architectures via a laser 3D printing technique. The as-printed 3D porous MG/Cu catalysts exhibit exceptional catalytic efficiency in degrading RhB with a normalized rate constant approximately 620 times higher than commercial nano zero-valent iron, outperforming most reported Fenton-type catalysts so far. Strikingly, the catalysts exhibit an excellent reusability and can be used more than 100 times (the highest record so far) without apparent efficiency decay. It is revealed that Cu-doping could improve the surface reducibility and promote the electronic transfer, rendering the 3D-printed MG/Cu catalysts with a sustainably active Fe(II)-rich surface and, therefore, unprecedented reusability. This work offers a broadly applicable design route for the development of advanced catalysts with an outstanding combination of activity and reusability for wastewater treatments.

Mechanism of metal sulfides accelerating Fe(II)/Fe(III) redox cycling to enhance pollutant degradation by persulfate: Metallic active sites vs. reducing sulfur species

Metal sulfides (MeS_x) have been found to be effective in enhancing pollutant degradation by Fenton-like reactions, but their role in persulfate (PS)-based oxidation processes as well as underlying mechanism have not been fully explored. In this study, effects of different MeS_x including WS₂, MoS₂, FeS₂ and ZnS on pollutant degradation by Fe²⁺/PS or Fe³⁺/PS systems were examined. It was found that the maximum degradation rate of 2,4,4'-trichlorobiphenyl increased by 5.6 and 16.2 times with the addition of WS₂ (0.2 g/L) in the Fe²⁺/PS and Fe³⁺/PS systems, respectively. Similar enhancement effects were also observed for MoS₂, FeS₂ and ZnS, which can enhance the degradation of a wide range of pollutants including sulfamethoxazole, bisphenol A and chlorophenol. The mechanism of these processes were further investigated, and it was observed that Fe(III)/Fe(II) redox cycles were dramatically accelerated on MeS_x surfaces, which increased PS activation to generate sulfate radicals and hydroxyl radicals, as evidenced by the combined analyses of surface Fe species, electron paramagnetic resonance and radical probing tests. Both surface metallic active sites and reducing sulfur species contributed to Fe(II) regeneration, but the efficiencies varied with the properties of MeS_x surface. This study provides a novel strategy for improving the performance of PS activation for environmental remediation and a comprehensive understanding of the mechanism of MeS_x enhancing Fenton-like reactions.

Remediation of Cu-phenanthrene co-contaminated soil by soil washing and subsequent photoelectrochemical process in presence of persulfate

A promising technology was proposed for the remediation of Cu and phenanthrene (PHE) co-contaminated soil. Firstly, Cu and PHE were simultaneously removed from soil using an extraction agent containing ethylenediaminetetraacetic acid (EDTA) and Tween 80 (TW80). Specifically, Cu was mobilized by the chelation of EDTA while PHE was desorpted from soil by TW80 micelles. At 20 mL g^-1 of liquid to soil ratio, 10 g L^-1 TW80 and 1 mM EDTA, 73.5% Cu and 68.1% PHE were removed by soil washing. The extraction agent was then recovered from effluent by photoelectro-persulfate (PE/PS) process after soil washing. Under the conditions of 10 mM PS, 4 mA cm^-2 current density, natural pH of 3.5 and 150 min treatment, 83.6% Cu was reduced to elemental copper but only 36.8% EDTA was recovered, while 99.6% PHE was eliminated and 94.0% TW80 was recovered. The result of quenching experiments indicated PHE was predominantly oxidized by sulfate radical, though hydroxyl radical and singlet oxygen were also identified by electron paramagnetic resonance technique. The recovered extracting agent could be reused for further three washing cycles. The results demonstrated that soil washing followed by PE/PS process could be a cost-effective remediation technology for heavy metal and organic co-contaminated soil.

Reactive oxygen species generation in FeOCl nanosheets activated peroxymonosulfate system: Radicals and non-radical pathways

Iron oxychloride (FeOCl) is utilized as a activator of peroxymonosulfate (PMS) for the degradation of paracetamol (APAP) and phenacetin (PNCT) in response to the water pollution by persistent pharmaceuticals. The degradation process was well fitted with a pseudo-first order kinetic pattern, and the excellent catalytic performance towards APAP (100 % removal) and PNCT (86.5 % removal) was obtained in the presence of 0.2 g/L FeOCl and 2.0 mM PMS at pH 7.0 in 30 min. In-situ electron spin resonance (ESR) and scavenging tests revealed the generation of a series of ROS (·OH, SO₄^-, O₂^-, ¹O₂), which was highly dependent on pH. Besides, the non-radical pathways process involved ¹O₂ was dominant in APAP oxidation, while both ·OH and ¹O₂ are significant in PNCT removal. Furthermore, the formation of disinfection by-products (DBPs) during post-chlorination showed neglectable increment at neutral and alkaline condition with FeOCl/PMS pre-oxidation, and the calculated cytotoxicity would experience a continuous deterioration with pH increase. These results displayed high efficiency of FeOCl/PMS system in micropollutants degradation and a relatively comprehensive activation process of PMS, which may promote practical application in environmental remediation.

Solid-Phase Microwave Reduction of WO3 by GO for Enhanced Synergistic Photo-Fenton Catalytic Degradation of Bisphenol A

The synergistic photocatalytic Fenton reaction is a powerful advanced oxidation technique for the degradation of persistent organic pollutants. However, microwave-induced thermal effects on the formation of novel structures facilitating the photocatalytic degradation have been rarely reported. Herein, a two-step microwave thermal strategy was developed to synthesize a new hybrid catalyst comprising defective WO_3-x nanowires coupled with reduced graphene oxides (rGOs). Conventionally, microwave methods could induce superhot spots on the GO surface, resulting in the site-specific crystallization and oriented growth of WO₃. However, in the solid phase, localized microwave thermal effects could reduce the interfacial area between WO₃ and rGO and enhance the bonding between them. As for the unique structure and surface properties, the synthesized catalyst enhanced the light absorption, promoted the interfacial charge separation, and increased the carrier density in the photocatalytic processes. In addition, surface formation of W⁴⁺ provided a new pathway for Fe³⁺/Fe²⁺ cycling which linked the photocatalytic reaction and the Fenton process. The optimized catalyst exhibited a remarkable performance in the degradation of bisphenol A with a ∼83% removal yield via a photo-Fenton route. These microwave-induced functionalities of materials for synergistic reactions could also give a new avenue to other photoelectrocatalytic fields and solar cells.