InP quantum dots on g-C3N4 nanosheets to promote molecular oxygen activation under visible light

Largely limited by the high dissociation energy of the OO bond, the photocatalytic molecular oxygen activation is highly challenged, which restrains the application of photocatalytic oxidation technology for atmospheric pollutants removal. Herein, we design and fabricate the InP QDs/g-C₃N₄ compounds. The introduction of InP QDs promotes the charge transfer within the interface resulting in the effective separation of photo-generated carriers. Furthermore, InP QDs greatly facilitates the activation of molecular oxygen and promote the formation of O₂⁻ under visible-light illumination. These conclusions are identified by experimental and calculation results. Hence, NO can be combined with the O₂⁻ to form OONO intermediate to direct conversion into NO₃⁻. As a result, the NO removal ratio of g-C₃N₄ has a onefold increase after InP QDs loaded and the generation of NO₂ is effectively inhibited. This work may provide a strategy to design highly efficient materials for molecular oxygen activation.     

Enhanced visible light photocatalytic activity of CeO2@Zn0.5Cd0.5S by facile Ce(IV)/Ce(III) cycle

In this study, CeO₂@Zn_0.5Cd_0.5S heterostructure (Ce@ZCS) is synthesized via a simple two-step hydrothermal method. The effect of CeO₂ loading on the visible-light photoactivity of Zn_0.5Cd_0.5S is mainly investigated. It is found that Ce@ZCS shows a 1.9 times activity as high as ZCS for the MB degradation. The improved activity mainly results from the significant enhanced charge separation by CeO₂, in which the electron transfer is obviously promoted by the facile Ce(IV)/Ce(III) cycle. The excited electrons of ZCS is easy to transfer to CeO₂, thus obviously increasing the charge separation of ZCS. The accepted electrons by CeO₂ may easily be captured by the adsorbed O₂ to form O₂⁻, and then O₂⁻ could combine with H⁺/H₂O to form HO₂, and OH. Finally, O₂⁻, h⁺ and OH are confirmed as the major oxidative species in photocatalytic reaction for Ce@ZCS, and a possible photocatalytic mechanism is proposed. The cheap, efficient Ce@ZCS photocatalyst could be applied for practical waste water treatment.     

Novel organic magnet derived from pyrazine-fused furazans

The first organic magnet based on a high-nitrogen framework of pyrazine-fused furazans Na(L⁻)(H₂O)₃ was found. A quantum-chemical study of M(L⁻)(H₂O)_n, where M = Li, Na, K, Rb, NH₄, revealed that exchange coupling energy between the neighboring radical anions proved highly sensitive to the motion of one L⁻ relative to another.     

Ultrafast O2 activation by copper oxide for 2,4-dichlorophenol degradation: The size-dependent surface reactivity

This study demonstrated interesting ultrafast activation of molecular O₂ by copper oxide (CuO) particles and very rapid elimination of aqueous 2,4-dichlorophenol (2,4-DCP) within reaction time of 30 s. Electron paramagnetic resonance (EPR) characterization indicated that OH, Cu³⁺, ¹O₂ and O₂⁻ were generated in the CuO/O₂ systems, wherein O₂⁻ would be the main reactive species responsible for 2,4-DCP degradation. It was further found that the catalytic ability of CuO for O₂ activation was highly size dependent and nano-CuO was far reactive than micro-CuO. H₂ temperature-programmed reduction (H₂-TPR), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analyses revealed that both the quantity and the reactivity of the surface reaction sites (surface Cu⁺ and O₂) could determine the catalytic ability of CuO affecting efficient Cu⁺-based molecular oxygen activation. Moreover, the O₂ activation ability of CuO would depend on not only the dimension, but also crystalline factors, for example, the exposed facets.     

Electro-catazone treatment of an ozone-resistant drug: Effect of sintering temperature on TiO2 nanoflower catalyst on porous Ti gas diffuser anodes

Electrochemical heterogeneous catalytic ozonation (E-catazone) is a promising and advanced oxidation technology that uses a titanium dioxide nanoflower (TiO_2-NF)-coated porous Ti gas diffuser as an anode material. Our previous study has highlighted that the importance of the TiO_2-NF coating layer in enhancing OH production and rapidly degrading O₃-resistant drugs. It is well known that the properties of TiO_2-NF are closely related to its sintering temperature. However, to date, related research has not been conducted in E-catazone systems. Thus, this study evaluated the effect of the sintering temperature on the degradation of the O₃-resistant drug para-chlorobenzoic acid (p-CBA) using both experimental and kinetic modeling and revealed its influence mechanism. The results indicated that the TiO_2-NF sintering temperature could influence p-CBA degradation and OH production. TiO_2-NF prepared at 450 °C showcased the highest p-CBA removal efficiency (98.5% in 5 min) at a rate of 0.82 min⁻¹, and an OH exposure of 8.41 × 10⁻¹⁰ mol L⁻¹ s. Kinetic modeling results and interface characterization data revealed that the sintering temperature could alter the TiO₂ crystallized phase and the content of surface-adsorbed oxygen, thus affecting the two key limiting reactions in the E-catazone process. That is, ≡TiO₂ surface reacted with H₂O to form TiO₂-(OH)₂, which then heterogeneously catalyzed O₃ to form OH. Consequently, E-catazone with a TiO_2-NF anode prepared at 450 °C generated the highest surface reaction rate (5.00 × 10⁻¹ s⁻¹ and 4.00 × 10^-3 L mol^-1 s⁻¹, respectively), owing to its higher anatase content and adsorbed oxygen. Thus, a rapid O₃-TiO₂ reaction was achieved, resulting in an enhanced OH formation and a highly effective p-CBA degradation. Overall, this study provides novel baseline data to improve the application of E-catazone technology.     

Oxygen dependent oxidation of trimethoprim by sulfate radical: Kinetic and mechanistic investigations

Trimethoprim (TMP) is a typical antibiotic to treat infectious disease, which is among the most commonly detected antibacterial agents in natural waters and municipal wastewaters. In the present study, the impacts of dissolved oxygen (DO) on the oxidation efficiency and pathways of TMP by reaction with sulfate radicals (SO₄⁻) were investigated. Our results revealed that the presence of DO was favourable for TMP degradation. Specifically, TMP would react initially with SO₄⁻ via electron-transfer process to form a carbon-centered radical. In the absence of oxygen, the carbon-centered radical could undergo hydrolysis to produce α-hydroxytrimethoprim (TMP−OH), followed by the further oxidation which generated α-ketotrimethoprim (TMP=O). However, in the presence of oxygen, the carbon-centered radical would alternatively combine with oxygen, leading to a sequential reaction in which peroxyl radical and a tetroxide were formed, and finally generated TMP−OH and TMP=O simultaneously. The proposed pathways were further confirmed by density functional theory (DFT) calculations. The results obtained in this study would emphasize the significance of DO on the oxidation of organic micro-pollutants by SO₄⁻.     

Photocatalytic degradation of sulfadiazine in suspensions of TiO2 nanosheets with exposed (001) facets

Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases. However, the release of these antibiotics has caused serious environmental problems. In this paper, photocatalytic oxidation technology was used to degrade sulfadiazine (SDZ), one of the typical sulfonamides antibiotics, in UV illuminated TiO₂ suspensions. It was found that TiO₂ nanosheets (TiO₂-NSs) with exposed (001) facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO₂ nanoparticles (TiO₂-NPs) with a rate constant increases from 0.017 min⁻¹ to 0.035 min⁻¹, improving by a factor of 2.1. Under the attacking of reactive oxygen species (ROSs) such as superoxide radicals (O₂^–) and hydroxyl radicals (OH), SDZ was steady degraded on the surface of TiO₂-NSs. Based on the identification of the produced intermediates by LC–MS/MS, possible degradation pathways of SDZ, which include desulfonation, oxidation and cleavage, were put forwards. After UV irradiation for 4 h, nearly 90% of the total organic carbon (TOC) can be removed in suspensions of TiO₂-NSs, indicating the mineralization of SDZ. TiO₂-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH. Even after recycling used for 7 times, more than 91.3% of the SDZ can be efficiently removed, indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.     

Graphdiyne as a novel nonactive anode for wastewater treatment: A theoretical study

Electrochemical oxidation of water to produce highly reactive hydroxyl radicals (OH) is the dominant factor that accounts for the organic compounds removal efficiency in water treatment. As an emerging carbon-based material, the investigation of electrocatalytic of water to produce OH on Graphdiyne (GDY) anode is firstly evaluated by using first-principles calculations. The theoretical calculation results demonstrated that the GDY anode owns a large oxygen evolution reaction (OER) overpotential (η^OER = 1.95 V) and a weak sorptive ability towards oxygen evolution intermediates (HO*, not OH). The high Gibbs energy change of HO* (3.18 eV) on GDY anode makes the selective production of OH (ΔG = 2.4 eV) thermodynamically favorable. The investigation comprises the understanding of the relationship between OER to electrochemical advanced oxidation process (EAOP), and give a proof-of-concept of finding the novel and robust environmental EAOP anode at quantum chemistry level.     

New insight in the O2 activation by nano Fe/Cu bimetals: The synergistic role of Cu(0) and Fe(II)

This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac (DCF), as compared to much slow removal of DCF by Cu(II) or zero valent iron nanoparticles (nZVI), respectively. Further observations on the evolution of O₂ activation process by nano Fe/Cu bimetals was conducted stretching to the preparation phase (started by nZVI/Cu²⁺). Interesting breakpoints were observed with obvious sudden increase in the DCF degradation efficiency and decrease in solution pH, as the original nZVI just consumed up to Fe(II) and Cu(II) appeared again. It suggested that the four-electrons reaction of O₂ and Cu-deposited nZVI would occur to generate water prior to the breakpoints, while Cu(0) and Fe(II) would play most important role in activation of O₂ afterwards. Through the electron spin resonance (ESR) analysis and quenching experiments, OH was identified as the responsible reactive species. Further time-dependent quantifications in the cases of Cu(0)/Fe(II) systems were carried out. It was found that the OH accumulation was positively and linearly correlated with nCu dose, Fe(II) consumption, and Fe(II) dose, respectively. Since either Cu(0) or Fe(II) would be inefficient in activating oxygen to produce OH, a stage-evolution mechanism of O₂ activated by nano Fe/Cu bimetals was proposed involving: (a) Rapid consumption of Fe(0) and release of Fe(II) based on the Cu-Fe galvanic corrosion, (b) adsorption and transformation of O₂ to O₂²⁻ at the nCu surface, and (c) Fe(II)-catalyzed activation of the adsorbed O₂²⁻ to OH.     

Pretreatment of polyvinyl alcohol by electrocoagulation coupling with catalytic oxidation: Performance,mechanism and pathway

In this study, various conditions for the removal of polyvinyl alcohol (PVA) by electrocoagulation (EC) coupled catalytic oxidation are systematically studied. The direct oxidation of the anode, the reduction of the cathode, the oxidation of OH and Cl, and the synergistic effect of flocculation on the degradation of polyvinyl alcohol are investigated. It is observed that the optimum experimental conditions obtained are as follows: Cell voltage 9 V, natural pH 7, NaCl concentration 0.02 mol/L, and interelectrode distance 3.0 cm. The evolution of iron ions is also discussed in the EC process. By contrast, EC had made an outstanding contribution to the removal of PVA, which removes 71.29% of PVA. Free radicals, especially OH and Cl, are equivalent to the contribution of the electrodes in the degradation of PVA. And the contribution of PVA degradation by anode oxidation and cathode reduction are 12.76% and 8.02%, respectively. Characterization of solution and floc, such as Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), GC–MS and molecular weight, showed that PVA is effectively removed by the EC process, and a possible degradation pathway is proposed     

Chitosan capped silver nanoparticles: Adsorption and photochemical activities

Chitosan capped silver nanoparticles (Chi-Ag) were prepared using AgNO₃ and sodium borohydride. Chitosan was detected by using ninhydrin test, thermal gravimetric analysis and measurement of relative viscosity. Chi-Ag was used for removal of cadmium (Cd²⁺) at room temperature. The maximum monolayer adsorption capacity, and sorption intensity were estimated to be 119.04 mg/g and 1.6, respectively, from Langmuir and Freundlich adsorption isotherm models. The kinetics of Cd²⁺ adsorption onto Chi-Ag was proceeds through the pseudo-second-order kinetic model. Boyd and Elovich models suggest the adsorption and/or coordination of Cd²⁺ with the NH₂ and OH groups of chitosan along with AgNPs proceeds through the film diffusion and chemisorption process. The average viscosity molecular weight of chitosan and Chi-Ag decreased with increased potassium persulfate (K₂S₂O₈) and hydrogen peroxide (H₂O₂) concentration. The presence of H₂O₂ and K₂S₂O₈ promoted the hydrolysis of chitosan due to the cleavage of glycosidic bond by generated HO and SO₄^? radicals.     

High active amorphous Co(OH)2 nanocages as peroxymonosulfate activator for boosting acetaminophen degradation and DFT calculation

Acetaminophen (ACE) is commonly used in analgesic and antipyretic drug, which is hardly removed by traditional wastewater treatment processes. Herein, amorphous Co(OH)₂ nanocages were explored as peroxymonosulfate (PMS) activator for efficient degradation of ACE. In the presence of amorphous Co(OH)₂ nanocages, 100% of ACE removal was reached within 2 min with a reaction rate constant k₁ = 3.68 min^?1 at optimum pH 5, which was much better than that of crystalline β-Co(OH)₂ and Co₃O₄. Amorphous materials (disorder atom arrangement) with hollow structures possess large specific surface area, more reactive sites, and abundant vacancies structures, which could efficiently facilitate the catalytic redox reactions. The radicals quenching experiment demonstrated that SO₄^? radicals dominated the ACE degradation rather than OH radicals. The mechanism of ACE degradation was elucidated by the analysis of degradation intermediates and theoretical calculation, indicating that the electrophilic SO₄^? and OH tend to attack the atoms of ACE with high Fukui index (f ^?). Our finding highlights the remarkable advantages of amorphous materials as heterogeneous catalysts in sulfate radicals-based AOPs and sheds new lights on water treatment for the degradation of emerging organic contaminants.     

Visible light induced efficient activation of persulfate by a carbon quantum dots (CQDs) modified γ-Fe2O3 catalyst

In this study, a carbon quantum dots modified maghemite catalyst (CQDs@γ-Fe₂O₃) has been synthesized by a one-step solvothermal method for efficient persulfate (PDS) activation under visible light irradiation. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS) characterization indicated that the formation of heterojunction structure between CQDs and γ-Fe₂O₃ effectively reduced the catalyst band gap (E_g), favoring the separation rate of electrons and holes, leading to remarkable efficient sulfamethoxazole (SMX) degradation as compared to the dark-CQDs@γ-Fe₂O₃/PDS and vis-γ-Fe₂O₃/PDS systems. The evolution of dissolved irons also demonstrated that CQDs could accelerate the in-situ reduction of surface-bounded Fe³⁺. Electron paramagnetic resonance (EPR) and radical scavenging experiments demonstrated that both OH and SO₄⁻ were generated in the reaction system, while OH was relatively more dominant than SO₄⁻ for SMX degradation. Finally, the reaction mechanism in the vis-CQDs@γ-Fe₂O₃/PDS system was proposed involving an effective and accelerated heterogeneous-homogeneous iron cycle. CQDs would enrich the photo-generated electrons from γ-Fe₂O₃, causing efficient interfacial generation of surface-bond Fe²⁺ and reduction of adsorbed Fe³⁺. This visible light induced iron cycle would eventually lead to effective activation of PDS as well as the efficient degradation of SMX.     

Efficient removal of tetracycline in water by a novel chemical and biological coupled system with non-woven cotton fabric as carrier

As a novel wastewater treatment strategy, the intimate coupling of photocatalysis and biodegradation (ICPB) has been attracted attention, which is ascribed to its combination of the advantages of photocatalytic reactions and biological treatment. The selection of carriers is important since it affects the stability of the system and the removal efficiency of pollutants. In this study, a novel ICPB system was successfully constructed by loading photocatalytic materials (i.e., TiO₂, N-TiO₂, and Ag-TiO₂) and microbes onto non-woven cotton fabric. The photocatalysts were characterized by scanning electron microscope-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). This system exhibited good performance in degrading tetracycline (TC) in water. The results showed that Ag-TiO₂-ICPB had the maximum removal efficiency of tetracycline (94.7%) in 5 h, which was 16.5% higher than the photocatalysis alone. After five cycles, 82.9% of tetracycline could be still degraded through Ag-TiO₂-ICPB. SEM spectrum showed microbes on the material changed little before and after the reactions. This result implied the materials were stable, and then beneficial for degrading of pollutants continuously. The intermediates were detected through ultraperformance liquid chromatography-mass spectrometer (UPLC-MS) and the plausible degradation pathways were proposed. Electron paramagnetic resonance (EPR) analysis showed OH and O₂⁻ were the main reactive oxygen species for TC degradation. In conclusion, the ICPB system with non-woven cotton fabric as a carrier has certain application prospects for antibiotic-containing wastewater.     

Copper-catalyzed synthesis of oxime ethers from iminoxy radical (CN–O) and maleimides via radical addition

An efficient Cu(II)-catalyzed radical addition of maleimides has been achieved. The identified copper catalyst enables the formation of oxime radicals (N–O) by cleaving the O–H bond in ketoximes, followed by the radical addition to N-substituted maleimides. The oxime radicals (N–O) were detected and confirmed by EPR spectroscopy and variable-temperature ¹H NMR. The simple one-pot reaction realizes the facile preparation of a variety of oxime ether adduct products in moderate to good yields.     

Effective removal of chlorinated organic pollutants by bimetallic iron-nickel sulfide activation of peroxydisulfate

Chlorinated organic pollutants(COPs) have caused serious contaminants in soil and groundwater,hence developing methods to remove these pollutants is necessary and urgent.By a simple hydrothermal method,we synthesized the bimetallic iron-nickel sulfide(FeNiS) particles which exhibited excellent catalytic property of COPs removal.FeNiS was chosen as the peroxydisulfate(PDS) activator to removal COPs including 4-chlorophenol(4-CP),1,4-dichlorophenol(1,4-DCP) and 2,4,6-trichlorophenol(2,4,6-TCP).The results show that FeNiS can efficiently activate PDS to produce sulfate radical(SO_4~(·-)) which plays major role in the oxidative dechlorination and degradation due to its strong oxidizing property and the ability of producing hydroxyl radicals(~·OH) in the alkaline condition.Meanwhile,the Cl-abscised from COPs during the dechlorination can turn into the chlorine radicals and enhance the degradation and cause further mineralization of intermediate products.This bimetallic FeNiS catalyst is a promising PDS activator for removal of chlorinated organics.     

Glycidyl ether of naturally occurring sesamol in the synthesis of mussel-inspired polymers

The objective of this work is to synthesize the mussel-mimicking ionic polymers bearing electron-rich 1,3,4-triphenoxy motifs of naturally occurring sesamol [3,4-(methylenedioxy)phenol] I. To our knowledge, the work would represent, for the first time, the ring-opening reaction of epoxide built upon the triphenoxy motifs of hydroxyhydroquinone. Sesamol I upon O-alkylation using epibromohydrin has been converted to its epoxy monomer II in 77% yield. Monomer II under ring-opening polymerization using basic Bu₄NOH and Bu₄NF as well as by Lewis acid initiator/catalyst MePh₃PBr/ⁱBu₃Al led to polyether III in 80–99% yields. Monomer II and allyl glycidyl ether (i.e. allyl 2,3-epoxypropyl ether) IV upon polymerization gave random copolymer V of number average molar mass of 9570 g mol⁻¹, which upon thiol-ene reaction with HSCH₂CH₂NH₃⁺Cl⁻ and HSCH₂CO₂H afforded cationic (^^^NH₃⁺) VI and anionic (^^^CO₂⁻) VII copolymers, respectively. For facile deprotection, the methylenedioxy (OCH₂O) motifs in VI was activated by its conversion to labile acetoxymethylenedioxy [OCH(OAc)O] unit to obtain VIII in 80% yields. The pendant allyl groups in VIII upon elaboration via thiol-ene reaction using cysteamine hydrochloride and subsequent hydrolysis of [OCH(OAc)O] under a mild condition led to a mussel-inspired cationic copolymer IX (78%) having catechol motifs-embedded pendants of 3,4-dihydroxyphenoxy groups.     

Effects of exogenic chloride on oxidative degradation of chlorinated azo dye by UV-activated peroxodisulfate

Recently, the degradation of organic compounds in saline dye wastewater by sulfate radicals (SO₄⁻)-based advanced oxidation processes (AOPs) have attracted much attention. However, previous studies on these systems have selected non-chlorinated dyes as model compounds, and little is known about the transformation of chlorinated dyes in such systems. In this study, acid yellow 17 (AY-17) was selected as a model of chlorinated contaminants, and the degradation kinetics and evolution of oxidation byproducts were investigated in the UV/PDS system. AY-17 can be efficiently degraded (over 98% decolorization) under 90 min irradiation at pH 2.0–3.0, and the reaction follows pseudo-first order kinetics. Cl^‒ accelerated the degradation of AY-17, but simultaneously led to an undesirable increase of absorbable organic halogen (AOX). Several chlorinated byproducts were identified by liquid chromatography-mass spectrometry (LC–MS/MS) in the UV/PDS system. It indicates that endogenic chlorine and exogenic Cl^– reacted with SO₄⁻ to form chloride radicals, which are involved in the dechlorination and rechlorination of AY-17 and intermediates. The possible degradation mechanisms of AY-17 photooxidative degradation are proposed. This work provides valuable information for further studies on the role of exogenic chloride in the degradation of chlorinated azo dyes and the kinetic parameters in the PDS-based oxidation process.     

Functional groups to modify g-C_3N_4 for improved photocatalytic activity of hydrogen evolution from water splitting

Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride(g-C_3 N_4).Herein,g-C_3 N_4 with yellow(Y-GCN) and brown(C-GCN) were prepared by using the fresh urea and the urea kept for five years,respectively,for the first time.Experimental results show that the H2 production rate of the C-GCN is 39.06 μmol/h,which is about 5 times of the Y-GCN.Meantime,in terms of apparent quantum efficiency(AQ.E) at 420 nm,C-GCN has a value of 6.3% and nearly 7.3 times higher than that of Y-GCN(0.86%).The results of XRD,IR,DRS,and NMR show,different from Y-GCN,a new kind of functional group of —N=CH— was firstly in-situ introduced into the C-GCN,resulting in good visible light absorption,and then markedly improving the photocatalytic performance.DFT calculation also confirms the effect of the —N=CH— group band structure of g-C_3N_4.Furthermore,XPS results demonstrate that the existence of —N=CH— groups in C-GCN results in tight interaction between C-GCN and Pt nanoparticles,and then improves the charge separation and photocatalytic performance.The present work demonstrates a good example of "defect engineering" to modify the intrinsic molecular structure of g-C_3N_4 and provides a new avenue to enhance the photocatalytic activity of g-C_3N_4 via facile and environmental-friendly method.     

Facile defect engineering in ZnIn2S4 coupled with carbon dots for rapid diclofenac degradation

Semiconductor-mediated photocatalysis is a promising photochemical process for harvesting inexhaustible solar energy to address the energy crisis and environmental issues. However, the low solar-light response and poor carrier migration are severe drawbacks that limit its practical application. Herein, we propose a convenient pathway for improving electron-hole separation and solar energy utilisation by engineering defective ZnIn₂S₄ with doping of carbon dots. The optimum ZnIn₂S₄/CD200 nanosheet exhibited 100% diclofenac (DCF) degradation within 12 min under visible-light. The estimated photocatalytic efficiency under natural sunlight was 98.2%. Scavenging experiments and electron spin resonance (ESR) analysis indicated that the superoxide radical (O₂⁻), photoelectron (e⁻), hole (h⁺) and hydroxyl radical (OH) were the predominant contributions in the ZnIn₂S₄/CD200/DCF/visible light system. Furthermore, ZnIn₂S₄/CD200 exhibited excellent reusability and stability after 4 times recycling. The photodegradation routes mainly involved hydroxylation, decarboxylation, CN bond cleavage, dechlorination, ring closure, and ring-opening. The ecological risk assessment and total organic carbon (TOC) tests exhibited desirable toxicity reduction and mineralization results. These observations not only offer a facile strategy for the construction of defective ZnIn₂S₄, but also pioneer the direct utilisation of natural light for highly efficient environmental remediation.