Z-scheme Photocatalysis Research Articles

Construction of Bi2WO6 composites with carbon-coated Cu2O for effective degradation of tetracycline

It is of great significance to achieve superior degradation of contaminants by developing efficient and stable photocatalysts. To boost the photocatalytic performance of Bi2WO6 for tetracycline degradation, the Bi2WO6 composites (Bi2WO6/C@Cu2O) were constructed by introducing Cu2O coated by carbon layer (C@Cu2O with 5 wt% of Bi2WO6) in this study. Bi2WO6/C@Cu2O presents an excellent performance on tetracycline degradation because of the generation of more active species as ∙O2- and ∙OH. Its kinetic rate constant k was 2.8 times of pure Bi2WO6 and tetracycline degradation efficiency maintained outstanding stability even after 4 cycles. This benefits from the higher photogenerated charge separation and electron transfer possessed by Bi2WO6/C@Cu2O compared to Bi2WO6. Various intermediates of tetracycline degradation were identified and the possible degradation pathways were proposed. The tetracycline degradation by Bi2WO6/C@Cu2O followed a Z-scheme photocatalysis mechanism. In addition to acting as the protective layer of Cu2O to attenuate the photo-corrosion of Cu2O, the oxygen containing functional groups CO on the surface of carbon layer could provide an electron transfer channel between the interface of Bi2WO6 and Cu2O to reduce the interfacial charge-transfer resistance and accelerate the electron transfer.

Electron transfer via a carbon channel for efficient Z-scheme solar hydrogen production

Z-scheme photocatalysis provides a promising solution to photocatalytic solar water splitting, yet restricted by inferior interfacial charge transfer. Here, we demonstrate a Z-scheme composite photocatalyst made of Fe2O3, a carbon layer, and g-C3N4 that can achieve efficient hydrogen generation from solar water decomposition. The success relies on in-situ preparation of core-shell Fe2O3@C structure at the surface of g-C3N4. Carbon as an intermediate layer thus acts as a bridge that significantly accelerates the migration of photogenerated electrons from Fe2O3 conduction band to g-C3N4 valence band. As a result, the highest rate of H2 generation reaches 5.26 mmol h−1g−1. This activity is approximately 33-time greater than that achieved over pristine g-C3N4 and about 4-time larger than that obtained over a Fe2O3/g-C3N4 heterojunction without internal carbon layer. This work explicates the potential insight of the composite and paves a promising way to engineer the charge transfer behavior.

Surface Modifications of (ZnSe)0.5(CuGa2.5Se4.25)0.5 to Promote Photocatalytic Z-Scheme Overall Water Splitting

Charge separation is crucial for an efficient artificial photosynthetic process, especially for narrow-bandgap metal sulfides/selenides. The present study demonstrates the application of a p-n junction to particulate metal selenides to enhance photocatalytic Z-scheme overall water splitting (OWS). The constructed p-n junction of CdS-(ZnSe)0.5(CuGa2.5Se4.25)0.5 significantly boosted charge separation. A thin TiO2 coating layer also was introduced to inhibit photocorrosion of CdS and suppress the backward reaction of water formation from hydrogen and oxygen. By employing Pt-loaded TiO2/CdS-(ZnSe)0.5(CuGa2.5Se4.25)0.5 as a hydrogen evolution photocatalyst (HEP), we assembled a Z-scheme OWS system, together with BiVO4:Mo and Au as an oxygen evolution photocatalyst and electron mediator, respectively. An apparent quantum yield of 1.5% at 420 nm was achieved, which is by far the highest among reported particulate photocatalytic Z-scheme OWS systems with metal sulfides/selenides as HEPs. The present work demonstrates that a well-tailored p-n junction structure is effective for promoting charge separation in photocatalysis and opens new pathways for the development of efficient artificial photosynthesis systems involving narrow bandgap photocatalysts.

Construction of a ternary Z-scheme In2S3@Au@P3HT photocatalyst for the degradation of phenolic pollutants under visible light

• In 2 S 3 @Au@P3HT heterojunction hybrids were successfully prepared by an in-situ technique. • Separation of electron/hole pairs and generation of oxidative species were enhanced. • A new type of Z-scheme photocatalysis system that was constructed using Au NPs. • Dual function with Phenolic degradation and Cr(VI) reduction. • A strategy for the construction of organic-inorganic hybrids is provided. A ternary nanoflower, In 2 S 3 @Au@P3HT, doped with gold nanoparticles and covered with a nanolayer P3HT, was prepared. The P3HT content was tuned for broader visible-light adsorption and higher photocurrents, whereas the Au NPs act as the charge transfer medium to construct a ternary Z-type heterojunction photocatalyst. The effective photocatalytic performance can be attributed to these synergistic benefits and was verified by applying the nanoflower to water remediation. Phenol, an organic pollutant that does not readily degrade, was chosen for photo-oxidative degradation. Application of the In 2 S 3 @Au@P3HT nanocomposites resulted in rapid degradation with almost 95% of the phenol (10 ppm) being degraded within 80 min. A new strategy for the preparation of this highly-efficient photocatalyst is provided.

Theoretical progress on direct Z-scheme photocatalysis of two-dimensional heterostructures

Two-dimensional (2D) materials, due to its excellent mechanical, unique electrical and optical properties, have become hot materials in the field of photocatalysis. Especially, 2D heterostructures can well inhibit the recombination of photogenerated electrons and holes in photocatalysis because of its special energy band structures and carrier transport characteristics, which are conducive to enhancing photoenergy conversion capacity and improving oxidation and reduction ability, so as to purify pollutants and store energy. In this minireview, we summarize recent theoretical progress in direct Z-scheme photocatalysis of 2D heterostructures, focusing on physical mechanism and improving catalytic efficiency. Current challenges and prospects for 2D direct Z-scheme photocatalysts are discussed as well.

Z-scheme transition metal bridge of Co9S8/Cd/CdS tubular heterostructure for enhanced photocatalytic hydrogen evolution

Narrow band gap semiconductors heterojunction with superior coupling and composition matching can enhance light absorption, reduce carrier recombination and increase redox activity. Here, we report Co9S8/Cd/CdS Z-scheme type heterojunctions with hierarchical tubular heterostructure and inexpensive transition metallic electronic bridge between two distinct semiconductors by a simultaneous immobilization and in-situ reduction strategy. The designed heterostructure greatly promotes the redox activity owing to high-density catalytic sites, excellent visible light capture by small band gap Co9S8/CdS and hollow framework in conjunction with fast charge separation and smooth transfer through intermediary conductive Cd. The optimized photocatalyst exhibits a hydrogen generation rate up to 10.42 μmol h−1 without obvious drop in performance over multiple cycles. The structural design, matching tandem constituent and continuous phase mediator are the pivotal factors to engender an efficient solid-state Z-scheme photocatalysis. The facile synthetic approach and noble metal free tandem structure of this work provide alternative avenues for the development of heterojunction photocatalysts for efficient solar-to-chemical conversion.

Bismuth-based Z-scheme photocatalytic systems for solar energy conversion

Charge transfer mechanism and application of Z-scheme photocatalysis.

Solar photocatalytic abatement of tetracycline over phosphate oxoanion decorated Bi2WO6/polyimide composites

Environmental-friendly solar photocatalytic technology is attracting great attention in the field of pollution control. In this work, novel PO43−-Bi2WO6/PI photocatalyst achieved high degradation efficiency for tetracycline degradation in simulated solar light (1.6 times kinetic constants of Bi2WO6). The photocatalyst could produce more oxygen vacancies as well as more active species O2− and OH, and exhibited high mineralization ability, good stability and recyclability simultaneously. After 4 cycles of degradation experiments, its degradation efficiency was only reduced by 8.6 %. Tetracycline molecules gradually became small molecules under the attack of active species. The tetracycline degradation was highly pH-dependent and enhanced with the increase of solution pH. The water quality parameters humic acid and Cl− presented the inhibitory effect, while HCO3− can accelerate the tetracycline degradation. The degradation of tetracycline by PO43−-Bi2WO6/PI conformed to the Z-scheme photocatalysis mechanism, which could effectively broaden the absorption of solar light, improve the separation and transfer of photogenerated electron-hole pairs and extend the lifespan of the photocatalyst.

Ternary ZnCdSO composite photocatalyst for efficient dye degradation under visible light retaining Z-scheme of migration pathways for the photogenerated charge carriers

Simple co-precipitation method followed by calcination was adopted to synthesize ZnCdSO ternary semiconductor photocatalyst. In the composite material highly crystalline and hexagonal wurtzite phase of ZnO along with hexagonal CdS and cubic CdO phases were separately identified. Oxygen vacancies (VO) in ZnO network and CdO phase resulted in narrowing the optical band gap, facilitating increased visible light absorption. CdS–CdO phase mediated surface defects increased significantly over the core/bulk defects in pristine ZnO, which simultaneously acted as trap-sites for charge carriers and active adsorption-sites for dyes for photocatalytic degradation. In photocatalytic Z-scheme charge transfer mechanism CdS with a higher negative potential conduction band acted as efficient reduction site and created superoxide radical anions (O2•−), whereas ZnO and CdO both having lower valence band potential acted as efficient oxidation sites and created hydroxyl radicals (•OH). Spatial separation of photo-generated charge carriers enhanced their lifetime and facilitated creating superoxide and hydroxyl radicals which, by virtue of their powerful and respective reducing and oxidizing properties, efficiently degraded the dye molecules. The hydroxyl radicals (•OH) and holes (h+) dominantly contributed in sequence, in the dye degradation process, while electrons (e−) and superoxide radicals (O2•−) had gradually lesser inputs to the phenomenon, as evidently identified via radical scavenging experiment with optical absorption study. Thus, photoactive ternary ZnO–CdS–CdO composite, produced via formation of CdO phase upon low temperature (300 °C) calcination, offered a significantly photostable superior photocatalyst for efficient dye degradation under visible light via a double Z-scheme charge transfer mechanism.

Synergistic effects of plasma Z-scheme photocatalysis process for biogas conversion

Biogas can be an energy carrier and on-site conversion of biogas into syngas provides an alternative to reduce its utilization cost and to increase its energy density since CO2 can be converted into combustible contents. In this study, perovskite-type photocatalyst LaFeO3 (LFO) and Ag-LaFeO3/TiO2 (ALFTO) are prepared and combined with a spark discharge reactor to conduct biogas reforming. Next, to reduce the influence of H2S on reforming system, another photocatalyst BaTa0.7Nb0.3O3 (BTaNO) is added to form plasma Z-scheme photocatalysis system. Results indicate that packing ALFTO enhances syngas generation rate to 20.2 mol/kW h but the existence of H2S leads to deactivation of photocatalyst and restriction on discharge. Further introduction of BTaNO increases the stable discharge time of the reactor. Photocatalyst characterizations further indicate that there are interactions between plasma and photocatalyst to induce synergistic effects and Z-scheme photocatalysis is beneficial to alleviate the impact of H2S on biogas reforming.

New porphyrin/Cu(II) porphyrin-TiO2 nanohybrids for improved photocatalytic oxidation and reduction activities

Two new porphyrins 5,10,15,20-tetra[3-((ethoxycarbonyl)propoxy)phenyl] porphyrin (H2Pp1), 5,10,15,20-tetra[3-((carboxyl)propoxy)phenyl] porphyrin (H2Pp2) and their copper porphyrins (CuPp1, CuPp2) were synthesized and characterized spectroscopically. The corresponding porphyrin/Cu(II) porphyrin-TiO2 nanohybrids (H2Pp1-TiO2, H2Pp2-TiO2, CuPp1-TiO2, CuPp2-TiO2) were then prepared and characterized. These nanohybrids have the same anatase structure as bare TiO2 with BET specific surface area of 117.96–151.76 m2 g−1. There exists the heterojunction at the interface of porphyrin/Cu(II) porphyrin and TiO2 within nanoscale. The photocatalytic performances of these nanohybrids were investigated by 4-NP oxidative degradation, as well as reduction to 4-AP. These photocatalysts exhibit high photocatalytic activities compared with bare TiO2 and individual porphyrin/Cu(II) porphyrin. With CuPp2-TiO2 as photocatalyst, the 4-NP degradation can be finished within 25 min, and 4-NP is reduced to 4-AP in 6 min. The main active species are photogenerated hole, hydroxyl radical and superoxide free radical during the photodegradation of 4-NP. The possible photocatalytic Z-scheme mechanism is suggested. In this case, the photogenerated holes from VB of TiO2 and electrons from CB of H2Pp/CuPp are the main drive force for the high photocatalytic activity.

A direct oxygen vacancy essential Z-scheme C@Ti4O7/g-C3N4 heterojunctions for visible-light degradation towards environmental dye pollutants

The unique C@Ti4O7/g-C3N4 photocatalyst was synthesize via wet chemical and annealing & calcining method, which was gifted both the intrinsic oxygen vacancies as well as Z-scheme heterojunction nature in structure. Such a unique three-dimensional structure exhibited exceptional photodegradation performance for the dye simulations system (Rhodamine B (RhB), methylene blue (MB) and methyl orange (MO)) under visible light irradiation, which is better than a single component and Anatase-TiO2. Subsequently, a possible photocatalytic Z-scheme mechanism was proposed to further illustrate the effective separation of photogenerated electron-hole pairs in C@Ti4O7/g-C3N4 based on structure and electrochemical characterizations results, which will help to better understand the nature of Z-scheme heterojunctions.

New Modified Sol–Gel Method for the Preparation KNb3O8 as a Hydrogen Evolution Photocatalyst in Z-Scheme Overall Water Splitting

The layered potassium niobate, KNb3O8, is evident as a photocatalyst for hydrogen production from water splitting under UV light. We hereby reported a new modified sol–gel method for the preparation of potassium niobate photocatalyst. Photocatalytic water splitting has been improved in this work by loading Pt nanoparticles as cocatalyst. The catalysts were characterized by powder X-ray diffraction (XRD), Ultraviolet–Visible spectroscopy (UV–Vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Their photocatalytic activities were in (i) an aqueous MeOH, used as sacrificial hole scavengers for hydrogen production and (ii) a new Z-scheme photocatalytic water splitting system where Pt/KNb3O8 was used for H2 evolution and Pt/WO3 was used for O2 evolution. The I−/IO3− aqueous solution was used as redox couple for the photocatalytic Z-scheme over all water splitting under UV light irradiation. The photocatalysts were prepared by loading platinum on sol–gel synthesis KNb3O8 and commercial WO3 via impregnation method. We find that, this KNb3O8 belonging to a orthorhombic structure with rod-like morphology. The Pt nanoparticles were sufficiently well-dispersed on the surface of photocatalyst, and enhanced photocatalytic properties. Our results show that I− concentration significantly influenced the photocatalytic activity. The combination of Pt/KNb3O8 with Pt/WO3 achieves a high H2 evolution rate (539 μmol g−1 h−1) and O2 evolution rate (140 μmol g−1 h−1) in 2 mM NaI solution.

Synergy of charge pre-separation and direct Z-scheme bridge in BiVO4{0 4 0}/Ag6Si2O7 photocatalyst boosting organic pollutant degradation

The rapid recombination and poor redox capability of photoinduced charge carriers seriously impede the photocatalytic activity. Herein, a direct Z-scheme photocatalyst was fabricated by selectively depositing Ag6Si2O7 nanoparticles (NPs) on the {0 4 0} facets of BiVO4. Owing to the facet-dependent band structure of BiVO4, the photoinduced electrons and holes can be pre-separated upon photoillumination and transfer to {0 4 0} and {1 1 0} facets of BiVO4, respectively. A rapid combination of the separated electrons at the {0 4 0} facets of BiVO4 with holes of the Ag6Si2O7 NPs then takes place triggering a direct Z-scheme photocatalysis. Such a charge pre-separation triggered by the faceted BiVO4, together with Z-scheme at the interface warrants not only effective photoinduced charge separation but also excellent redox capability owing to the increased redox potential. The photocatalytic rate constant of the optimum BiVO4{0 4 0}/Ag6Si2O7 heterostructure is 28.2 and 17.2 times higher than those of pristine BiVO4 and Ag6Si2O7, respectively. This study offers a new insight for constructing direct Z-scheme photocatalysts with high degradation efficiency based on facet-controlled crystals.

Novel all-solid-state Z-scheme SnO2/Pt/In2O3 photocatalyst with boosted photocatalytic performance on water splitting and 2,4-dichlorophenol degradation under visible light

Fabricating Z-scheme photocatalytic system is of great significance for water splitting and degradation of organic pollutants. However, it is highly challenging to select suitable materials to form Z-scheme photocatalysis systems due to the harsh requirement for band edge levels alignment and interfacial contact. In this work, a novel all-solid-state Pt-bridge SnO2/Pt/In2O3 Z-scheme photocatalyst was prepared by an ingenious in situ deposition and photo-reduction protocol. The physicochemical properties of prepared materials were characterized via SEM, TEM, BET, DRS, PL, and EIS. It is revealed that the visible light absorption capacity of prepared composites was remarkably enhanced due to the localized surface plasma resonance effect of Pt nanoparticles. Moreover, such Pt nanoparticles act as the electron mediator of photogenerated carriers, and the photogenerated electron hole pairs of SnO2/Pt/In2O3 Z-scheme photocatalysts can be effectively separated, which hence reserving the most favorable reductive and oxidative reaction sites. The photocatalytic degradation efficiency of 2,4-dichlorophenol (50 mg L−1) over SnO2/Pt/In2O3 under visible light reaches 90% in 180 min, and the optimal photocatalytic H2 generation rate reaches 967.018 μmol h−1 g−1, respectively more than 9.36 and 19.40 times higher than that of pure In2O3 (103.358 μmol h−1 g−1) and SnO2 (49.847 μmol h−1 g−1). In addition, the stability experiments showed that the H2 generation rate of the SnO2/Pt/In2O3 Z-scheme photocatalyst after five cycles has only decreased by 8.96%. This work not only demonstrates a facile and eco-friendly strategy to prepare highly active and stable photocatalyst, but provides a new viewpoint about designing and constructing novel Z-scheme photocatalytic materials.

Al cluster oxide modified a hematite/P3HT ternary Z-scheme photocatalyst with excellent photocatalytic performance: A discussion of the mechanism

The Z-scheme photocatalyst is valuable for use in polluted water purification, and there is a need to develop a cheap and efficient photocatalyst. This study presents a new type of Z-scheme photocatalytic material composed of hematite and P3HT, also, the Al cluster oxides were first used as a charge transfer mediator to construct Z-scheme photocatalysis system. In addition, by analyzing the electron rearrangement phenomenon exhibited by the XPS spectrum and the experimental results of the in-situ illumination XPS, it is found that Al cluster is beneficial to the electron multi-step charge transfer process and Al cluster favors the construction of Z-scheme structure between hematite and P3HT. This Poly-3-hexylthiophene (P3HT)/Al cluster oxide/hematite ternary photocatalyst exhibited an excellent degradation effect on bisphenol A and tetracycline. This study demonstrates the feasibility of using the Al cluster as a charge mediator in the Z-scheme, providing new Z-scheme catalyst construction idea which is beneficial to the popularization and use of Z-scheme system in practical applications, and providing a new material for water pollution purification.

Ag as Cocatalyst and Electron-Hole Medium in CeO2 QDs/Ag/Ag2Se Z-scheme Heterojunction Enhanced the Photo-Electrocatalytic Properties of the Photoelectrode.

A recyclable photoelectrode with high degradation capability for organic pollutants is crucial for environmental protection and, in this work, a novel CeO2 quantum dot (QDs)/Ag2Se Z-scheme photoelectrode boasting increased visible light absorption and fast separation and transfer of photo-induced carriers is prepared and demonstrated. A higher voltage increases the photocurrent and 95.8% of tetracycline (TC) is degraded by 10% CeO2 QDs/Ag2Se in 75 minutes. The degradation rate is superior to that achieved by photocatalysis (92.3% of TC in 90 min) or electrocatalysis (27.7% of TC in 90 min). Oxygen vacancies on the CeO2 QDs advance the separation and transfer of photogenerated carriers at the interfacial region. Free radical capture tests demonstrate that •O2−, •OH, and h+ are the principal active substances and, by also considering the bandgaps of CeO2 QDs and Ag2Se, the photocatalytic mechanism of CeO2 QDs/Ag2Se abides by the Z-scheme rather than the traditional heterojunction scheme. A small amount of metallic Ag formed in the photocatalysis process can form a high-speed charge transfer nano channel, which can greatly inhibit the photogenerated carrier recombination, improve the photocatalytic performance, and help form a steady Z-scheme photocatalysis system. This study would lay a foundation for the design of a Z-scheme solar photocatalytic system.

Perspective and status of polymeric graphitic carbon nitride based Z-scheme photocatalytic systems for sustainable photocatalytic water purification

• Exploration of basic principle of Z-scheme photocatalysis. • Selection of Z-scheme photocatalysts for photocatalytic environment applications. • Discussion on g-C 3 N 4 based Z-scheme photocatalysts for pollutant degradation. • Applicability of Z-scheme photocatalysts for photocatalytic antibacterial activity. • View point on scope and limitations in g-C 3 N 4 based Z-scheme photocatalysis. Developing bioinspired artificial Z-scheme heterojunction photocatalysts with exceedingly well performance of visible-light harnessing along with optimum band edge potentials is a robustly prominent avenue to combat the environmental and energy crisis. The current scenario in fixation of water shortages all over the world is utilisation of green and economical processes to maintain sustainability. In this regard, hybridizing fascinating metal-free polymeric conjugated graphitic carbon nitride (g-C 3 N 4 ) with other components to tailor an effectual visibly driven photocatalyst has triggered a superfluity in the field of photocatalysis. Considering the great adherence and eloquent progress in exploitation of g-C 3 N 4 goaded Z-scheme nanohybrids, we herein present an all-inclusive and updated study about photocatalytic wastewater treatment including pollutant degradation and bacterial inactivation. An in-depth overview comprising traditional photocatalysis along with Z-scheme photocatalytic systems have been exploited and discussed with respect to their facile synthesis techniques and application in environmental restoration. With revamp strategies, g-C 3 N 4 based Z-scheme photocatalytic systems provide broad range visible light absorption and efficient space separation of photo-generated charge carriers, resulting in efficacious photoactivity. The mechanistic insights inferring photocarriers migration and separation along with the generation of reactive radical species involved in the photodegradation process has also been highlighted and discussed. Finally, an all-embracing conclusive remark is presented regarding present studies and future perspectives for the development of g-C 3 N 4 goaded Z-scheme photocatalysis.

Metal selenides for photocatalytic Z-scheme pure water splitting mediated by reduced graphene oxide

Exploration of novel narrow bandgap semiconductors for overall water splitting is vital for the realization of practical solar H 2 production. In the work, solid solutions of zinc selenide and copper gallium selenide with absorption edge wavelengths ranging from 480 to 730 nm were developed. Using these metal selenides as H 2 -evolving photocatalysts, CoO x /BiVO 4 as the O 2 -evolving photocatalyst, and reduced graphene oxide as the electron mediator, all-solid-state Z-scheme overall pure water splitting systems were constructed. The rate of photocatalytic H 2 evolution from aqueous solutions containing Na 2 S and Na 2 SO 3 as the electron donors was evaluated while employing these selenide photocatalysts at various Zn/(Zn+Cu) and Ga/Cu molar ratios. The data demonstrate that efficient Z-scheme overall water splitting was significantly correlated to the photoelectrochemical performance of the selenide photocatalysts acting as photocathodes, rather than the photocatalytic activities of these materials during the sacrificial H 2 evolution. Powder suspension Z-scheme pure water splitting systems employing narrow bandgap metal selenides, CoO x /BiVO 4 , and reduced graphene oxide as the H 2 evolving photocatalyst, O 2 evolving photocatalyst, and electron mediator, respectively, are demonstrated.

The carboxylate magnetic – Zinc based metal-organic framework heterojunction: Fe3O4-COOH@ZIF-8/Ag/Ag3PO4 for plasmon enhanced visible light Z-scheme photocatalysis

In this work, magnetic nanoparticles (MNPs) grafted with carboxylic acid (Fe3O4-COOH MNPs) were successfully prepared from incorporation of glutaric anhydride as a functional group on the surface of the ferrite NPs. The MNP was used as a template to induce the growth of ZIF-8 metal–organic framework (MOF) on its surface. The Fe3O4-COOH@ZIF-8 core-shell was incorporated with silver phosphate (Ag3PO4) and Ag nanoparticles (Ag NPs) to develop a visible light active Fe3O4-COOH@ZIF-8/Ag/Ag3PO4 photocatalyst. The materials were characterized using a range of techniques. The photocatalytic activity was investigated systematically by degrading an organo-phosphorus pesticide, diazinon under visible light irradiation. Among synthesized samples, the Fe3O4-COOH@ZIF-8/Ag/Ag3PO4 heterostructured system exhibited highest photocatalytic activity and improved stability compared to others for the degradation of diazinon under visible light. The superior activity and improved stability of this heterostructured photocatalyst was attributed to the synergistic effects from surface plasmon resonance (SPR) of Ag NPs and sequential energy transfer via Z-scheme mechanism, for effective separation of electron-hole pairs. Radical-trapping experiments demonstrate that holes (h+) and O2− are primary reactive species involved in photocatalytic oxidation process. Moreover, the Fe3O4-COOH@ZIF-8/Ag/Ag3PO4 photocatalyst did not show any obvious loss of photocatalytic activity during five cycle tests, which indicate that the heterostructured photocatalyst was highly stable and can be used repeatedly. Therefore, the work provides new insights into the design and fabrication of metal-organic frameworks (MOFs) for use as a visible light photocatalyst for degrading organic contaminants.