Separation Of Photoinduced Charge Carriers Research Articles

CdO decorated CdS nanorod for enhanced photocatalytic reduction of CO2 to CO.

Solar-driven CO2 reduction into fuels and sustainable energy has attracted increasing attention around the world. However, the photoreduction efficiency remains low due to the low efficiency of separation of electron-hole pairs and high thermal stability of CO2. In this work, we prepared a CdO decorated CdS nanorod for visible light driven CO2 reduction. The introduction of CdO facilitates the photoinduced charge carrier separation and transfer and acts as an active site for adsorption and activation of CO2 molecules. Compared with pristine CdS, CdO/CdS exhibits a nearly 5-fold higher CO generation rate (1.26 mmol g-1 h-1). In situ FT-IR experiments indicated that CO2 reduction on CdO/CdS may follow a COOH* pathway. This study reports the pivotal effect of CdO on photogenerated carrier transfer in photocatalysis and on CO2 adsorption, which provides a facile way to enhance photocatalytic efficiency.

Fabrication of noble-metal-free hierarchical rectangular tubular S-scheme NiS/ZnIn2S4/AgIn(WO4)2 nanocomposite for highly efficient photocatalytic hydrogen evolution

Accelerating the separation and transfer of photoinduced charge carriers is crucial for designing photocatalysts with superior photocatalytic hydrogen evolution (PHE) activity. Herein, a novel rectangular tubular hierarchical NiS/ZnIn2S4/AgIn(WO4)2 heterostructure was established by in-situ growing ZnIn2S4 nanosheets on the surface of tubular AgIn(WO4)2 and NiS nanoparticles (NPs) further deposited as co-catalysts for the first time. Based on the experimental and theoretical calculation results, the fabrication of ZnIn2S4/AgIn(WO4)2 S-scheme heterojunction as well as NiS NPs as active centers could account for the fast photogenerated charge carriers transfer and enhanced PHE activity. Notably, under simulated sunlight irradiation, the optimal NiS/ZnIn2S4/AgIn(WO4)2 composite exhibited a high PHE rate of 4818 µmol·g−1·h−1 without adding any noble-metal co-catalyst, which was about 24 and 3.7 times higher than that of pure AgIn(WO4)2 and ZnIn2S4, respectively. Meanwhile, the rate was up to 83 % of the value of ZnIn2S4/AgIn(WO4)2 with 3 wt% platinum (Pt) as co-catalyst, which meant that NiS NPs could replace Pt as an efficient noble-metal-free co-catalyst. This work provided a feasible approach to utilize the synergistic effect between co-catalyst and heterojunction for constructing efficient photocatalytic systems, and further confirmed the potential application of AgIn(WO4)2 with the special tubular morphology for PHE reaction.

Enhancement strategies for ZnSe based photocatalysts: Application to environmental remediation and energy conversion

In recent times, the increase in the growth of population and industries has become a major issue for environmental resources and energy. The foremost reason behind environmental pollution is the discharging of hazardous pollutants like antibiotics, pesticides, dyes, phenols, and heavy metal ions into the water, which cause the lack to access to pure water. The photocatalysis method, obtained from solar energy can surely be helpful for the improvement of the environment. Recently, Zinc selenide (ZnSe) is a noteworthy and admirable photocatalytic material that belongs to the II-VI group with a direct energy gap of 2.67 eV. Due to ZnSe good photocatalytic properties, it is a useful photocatalytic material in environmental remediation. The present review illustrated the structural and optoelectronic properties of ZnSe with theoretical studies. The density functional theory (DFT) computation was used to validate the structural characteristics and optoelectronic properties. Various modification strategies like doping, conventional heterojunctions, and Z-scheme heterojunctions have been illustrated which enhanced the photocatalytic activity of ZnSe. These strategies lower the recombination rate and enhance the photoinduced charge carrier separation and migration efficacy. Similarly, photocatalytic applications of ZnSe in pollutant degradation, Co2 reduction, H2 evolution, and Cr(VI) reduction have been highlighted with its photocatalytic mechanism. Finally, the review ended with a conclusion and emerging future challenges in the field of ZnSe photocatalysts for water purification.

Two dimensional MAX supported copper oxide/nickel Oxide/MAX as an efficient and novel photocatalyst for hydrogen evolution

An innovative 2D MAX structure comprising of Ti3AlC2 multilayers and copper oxide (CuO)/nickel oxide (NiO) (CN) composite was fabricated via a facile chemical route for improving photocatalytic hydrogen evolution activity. The physicochemical properties of the synthesized nanocomposites were analyzed through various structural, morphological, and elemental techniques. The 2D Ti3AlC2/CuO/NiO composite showed a maximum H2 generation rate of 20.7 mmol g−1 h−1, which is greater than that of the CN nanocomposite. This improved activity can be attributed to the presence of Ti3AlC2 multilayers on CuO/NiO, which showed excellent photoinduced charge carrier separation via the s-scheme mechanism. As an electron-bridge, CN NC can support the photoelectrons to transfer from the CB of CN to the CB of MAX, from where the photoelectrons respond with hydrogen ion to release hydrogen. The time-resolved photoluminescence measurement results showed that the CuO/NiO/MAX (CNM) composite had a charge carrier lifetime of 3 ns. The outcomes of this study will be beneficial in realizing the industrial applications of Ti3AlC2 MAX-based structured catalysts for hydrogen evolution and other ecological energy systems.

CuS anchored onto peanut-like BiVO4 p-n heterojunction with enhanced photocatalytic degradation activity under visible light irradiation

• Peanut-like CuS/BiVO 4 p-n heterojunctions were prepared by two-step hydrothermal method. • CuS/BiVO 4 composites exhibit high activity of glyphosate degradation under visible light. • The reaction rate constant of 8%CuS/BiVO 4 is 3.8 times greater than that of BiVO 4 . • CuS/BiVO 4 strongly promotes the separation of photoexcited electron and hole pairs. Seeking cheap photocatalysts for practical application is a great challenge. It is greatly significant to construct heterojunctions for the efficient separation of photoexcited carriers. Herein, a peanut-like CuS/BiVO 4 p-n heterojunction is prepared using thiourea as the raw material via a two-step hydrothermal process. The 8%CuS/BiVO 4 composite has many advantages, including excellent visible light absorption capacity, photoelectric performance, and enhanced glyphosate degradation rate by 3.8 times compared to BiVO 4 . The probable photocatalytic mechanism is proposed according to the XPS, DRS, photocurrent, PL, and experimental results. The intimate interface contact between CuS and BiVO 4 effectively achieves quick separation of photoinduced charge carriers and improves photocatalytic activity, thus enhancing degradation efficiency of glyphosate. The glyphosate degradation path is also investigated according to the intermediates detected by mass spectrometry.

Facile construction of a fascinating dual Z-scheme Bi2S3/tg-C3N4/α-Ag2WO4 photocatalyst for effective removal of organic pollutants: Influence factors, mechanism insight and degradation pathway

Inefficient utilization of sunlight response, low separation of photoinduced charge carriers, narrow redox potential and inferior recycling capacity significantly affects the functionalities of catalyst to get access in the practical wastewater treatment. A novel dual Z-scheme Bi2S3/tg-C3N4/α-Ag2WO4 ternary nanocomposite was designed and fabricated successfully to improve the absorption range of sunlight. The structural, optical, morphological, compositional and nitrogen adsorption-desorption properties of as-prepared pristine, binary and ternary photocatalysts were examined comprehensively. The 15 % Bi2S3/tg-C3N4/α-Ag2WO4 ternary nanocomposite demonstrated the highest degradation efficiency for toxic pollutants such as TC antibiotic (η = 95.02 %), MB (η = 98.94 %), RhB (η = 99.26 %) and MO (η = 77.35 %) under sunlight irradiation. The optimized 15 % Bi2S3/tg-C3N4/α-Ag2WO4 photocatalyst exhibits the reaction rate constant of TC antibiotic (k = 0.0209 min−1) was 3.6, 6.7 and 1.8 folds higher than that of pristine 1D-α-Ag2WO4, 1D-Bi2S3 and 2D-tg-C3N4. The favorable photocatalytic performance of dual Z-scheme heterojunction is attributed to a tight contact interface, good redox potential capacity, higher separation of photogenerated electron-hole pairs and inferior charge carriers recombination rate. The recycling tests reveal the attractive reusability and photostability of 15 % Bi2S3/tg-C3N4/α-Ag2WO4 photocatalyst. Moreover, the quenching experiment suggested that the holes (h+) radical play a dominant role in the photocatalytic activity process of toxic contaminants over 15 % Bi2S3/tg-C3N4/α-Ag2WO4 ternary nanocomposite. The possible reaction mechanism and degradation pathways of TC antibiotic were speculated with several characteristic intermediates identified. This present work deals with new understanding of the design and construction of dual Z-scheme heterojunction photocatalysts for wastewater remediation in an environmental application.

Enhancement of visible-light-driven oxidative amine coupling under aerobic and anaerobic conditions by photocatalyst with spatial separation of photoinduced charge carriers

Enhancement of visible-light-driven oxidative amine coupling under aerobic and anaerobic conditions by photocatalyst with spatial separation of photoinduced charge carriers

Trash to treasure: Green synthesis of novel Ag2O/Ag2CO3 Z-scheme heterojunctions with highly efficient photocatalytic activities derived from waste mussel shells

Shells, valuable renewable natural resources with particular mechanical properties and structures, are mostly abandoned as waste and accumulated in environment, leading to serious pollution and resource waste. To realize the high value reutilization and environmental protection, here, novel Ag-based photocatalysts were in-situ fabricated via a facile ball milling method using waste mussel shells as precursors for the first time. The composition, structure and photocatalytic activity of the obtained Ag-based photocatalysts can be regulated by the alkalinity of the reaction system caused by different treatments towards mussel shells. Among the obtained products, the Ag2O/Ag2CO3 Z-scheme heterojunctions with massive oxygen vacancies displayed the strongest visible-light photocatalytic ability and superior reusability in degrading sulfadiazine, which can be attributed to the wider light response region and faster separation of photoinduced charge carriers. Besides, the photocatalytic mechanism was speculated according to the tests of radicals trapping, electron spin resonance and simulation calculations, verifying the charge transfer direction and chief roles of ·O2− and h+ during the photocatalytic reaction. Above all, this study not only provides a convenient in-situ solid-state strategy to construct novel Ag-based photocatalysts with excellent photocatalytic activity, but also opens up a new perspective towards high value reutilization of waste shells in environmental remediation, “One Stone Two Birds” realizing the “control of waste by waste” and “trash to treasure”.

A novel Ag/g-C3N4/ZnO/Fe3O4 nanohybrid superparamagnetic photocatalyst for efficient degradation of emerging pharmaceutical contaminant (Pantoprazole) from aqueous sources

Owing to their remarkable properties, such as concentration of energetic photons, scattering of photons and demonstration of surface plasmon resonance (SPR), the use of plasmonic noble metals in the construction of a nanohybrid photocatalyst holds great promise of enhancing photodegradation rates. The current work puts forth a facile route of fabrication of a robust Ag/g-C3N4/ZnO/Fe3O4 hybrid, superparamagnetic nano-photocatalyst for express photodegradation of pantoprazole, a prototype of a pharmaceutical. The absorption edge of the nano-scaled hybrid photocatalyst was found to be ~ 2.25 eV suggesting fine-tuning of band edges of its moieties. Photoluminescence studies and photoelectrochemical investigations of the hybrid photocatalyst revealed a diminished rate of electron-hole recombination that further suggested enhanced separation of charge carriers attained through synergistic effects of individual moieties. g-C3N4 and Fe3O4 proved to be of immense consequence vis-à-vis separation of photoinduced charge carriers. Alone the photocatalyst achieved 98.24% disintegration of pantoprazole within 40 min with a stupendous pseudo-first order velocity constant of 0.10231 min−1. The performance of the quaternary photocatalyst was also evaluated in presence of various co-existing substances as well as in environmental water samples.

100% N2O inhibition in photocatalytic NOx reduction by carbon particles over Bi2WO6/TiO2 Z-scheme heterojunctions

The chemically inert property of nitrous oxide (N2O) has made it difficult to be reduced to benign dinitrogen during (photo) selective catalytic reduction (SCR) of NOx. The introduction of oxygen vacancies and BrØnsted acid sites to thermal catalysts is found to effectively inhibit N2O formation. However, the efficiency is still far from satisfactory and the inhibition of N2O in photocatalytic selective reduction of NOx has not been investigated yet. Herein, 100% inhibition of N2O formation during photo-SCR of NOx with carbon particles is successfully achieved via the fabrication of Bi2WO6/TiO2 Z-scheme heterojunction photocatalyst. The completely inhibited N2O formation is attributed to the rapid charge separation and stronger N2O adsorption on the (101) plane of TiO2 according to the density functional theory calculations and experimental results. The presence of water vapor prolongs the reaction time for NOx photo-reduction of carbon particles but has no significant effect on carbon oxidation rate. Introduction of heterostructure interface effectively accelerates photo-induced charge carrier separation and transfer, thereby enhancing photocatalytic efficiency for NOx reduction with carbon particles. The optimized 0.2 Bi2WO6/TiO2 (molar ratio) composite achieves the highest formal electron/photon quantum efficiency of 0.036, which is 3.3 times that of TiO2. The results provide an alternative perspective on the catalyst fabrication via the simple heterojunction materials for toxic byproduct control in the field of pollutants removal.

High-efficiency charge separation of Z-scheme 2D/2D C3N4/C3N5 nonmetal VdW heterojunction photocatalyst with enhanced hydrogen evolution activity and stability

The interfacial charge transfer control is a key and arduous issue for propelling the migration/separation of photogenerated carriers for heterojunction photocatalysts. Here, a new 2D/2D C3N4/C3N5 nonmetal van der Waals (VdW) heterojunction is fabricated by the simple self-assembly technique in acidic medium, whose charge separation efficiency is promoted dramatically, thus being endowed with the high-efficiency photocatalytic hydrogen evolution (PHE) performance. The PHE rate reaches up to 3.33 mmol h−1 g−1 under the visible light and the apparent quantum efficiency (AQE) of 20.6% is achieved at 420 nm on the optimal 2D/2D C3N4/C3N5-5% sample. Furthermore, the 2D/2D C3N4/C3N5 nonmetal VdW heterojunction also exhibits the desired stability because there was no significant decrease after PHE reaction of 10 cycles with total 40 h. Such outstanding PHE activity and stability originate from the impelled separation of photoinduced charge carriers and the powerful interfacial interaction through forming Z-Scheme charge transfer path and π-π coupling effect between C3N4 and C3N5 nanosheets. This work takes a significant guiding and demonstration for designing and exploiting other novel nonmetallic polymer-based VdW heterojunctions in the photocatalytic application field.

Ultrathin organic polymer with p-π conjugated structure for simultaneous photocatalytic disulfide bond generation and CO2 reduction

Combining photocatalytic organic reactions with CO2 reduction is an efficient solar energy utilization mode, but it is still limited by the organic species that can be matched and the low conversion. Herein, ultrathin organic polymer with p-π conjugated structure (TPP) was rationally designed and prepared, and showed a high yield of CO (15.2 mmol g−1) and conversion of SS coupled products (100%), far exceeding the organic polymer with PO structure. The enhanced photoredox activity of TPP is ascribed to the orbital interaction between the p-orbital on phosphorus and the π-orbitals of aromatic, which can accelerate the photoinduced charge carrier separation and improve the CO2 adsorption capacity. TPP can also be used for the dehydrocoupling of various benzyl mercaptans to the corresponding SS bond products. This work provides a new concept for the efficient synthesis of disulfide bonds combined with CO2 reduction in a photoreaction system.

A magnetically separable α-NiMoO4/ZnFe2O4/coffee biochar heterojunction photocatalyst for efficient ketoprofen degradation

In this study, a novel heterostructure i.e., ZnFe2O4 nanosphere-decorated α-NiMoO4 nanorods on coffee biochar (BC), was fabricated via a hydrothermal method. The magnetically separable α-NiMoO4/ZnFe2O4/BC composite demonstrated 98.65 % degradation of ketoprofen (KP) in 180 min under visible light irradiation. Analysis of cyclic tests, total organic carbon, and fluorescence excitation-emission matrices revealed the excellent stability and mineralization abilities of photocatalysts, respectively. The effects of influencing factors (pH, anions, and different concentrations of KP/photocatalysts) on degradation of KP by the photocatalysts were suggested as promising prospects in water/wastewater treatment. BC acts as a conductor and an electron mediator in heterostructure. The enhanced photocatalytic performance of the heterostructure was ascribed to increased visible light absorption and efficient photoinduced charge carrier separation. Furthermore, photoluminescence spectral and electrochemical investigations indicated the efficient separation of photoinduced charge carriers. Electron spin resonance spectroscopy and scavenger experiments demonstrated that •OH played a major role in KP degradation. According to the liquid chromatography-tandem mass spectroscopy analysis, KP was degraded via three degradation pathways by 24 degraded intermediates. This study provides a new perspective on fabrication of efficient heterojunction photocatalysts exhibiting good recovery and insight on mechanisms and pathways underlying KP degradation.

Impact of crystalline core/amorphous shell structured black TiO2 nanoparticles on photoelectrochemical water splitting

This work examined the influence of the annealing temperature on the preparation of crystalline core/amorphous shell structured black TiO2 nanoparticles in a vacuum. As the annealing temperature was increased from 200 to 500 °C, the visible light absorption increased, and the bandgap of the black TiO2 nanoparticles narrowed. The formation of oxygen vacancies was revealed by estimating the relative portion of Ti–O and Ti–OH species by XPS analysis. The growth of amorphous shell on the crystalline core of the black TiO2 nanoparticles was demonstrated by TEM micrographs. The photocurrent density was enhanced greatly by altering the band edge positions of valence and conduction bands to form a crystalline core/amorphous shell structure. The enhancement was ascribed to the efficient separation of photoinduced charge carriers. A possible mechanism for the enhanced photoelectrochemical water splitting activity was proposed based on the crystalline core/amorphous shell structure of the black TiO2 nanoparticles.

Synchronous synthesis of S-doped carbon nitride/nickel sulfide photocatalysts for efficient dye degradation and hydrogen evolution

Rational design of photocatalysts with low-cost and high-efficiency is of great significance for environmental remediation and energy utilization. Herein, the NiS-loaded on S-doped carbon nitride photocatalysts were synchronous synthesized via one-pot hydrothermal method. The activities of the photocatalysts were evaluated by photodegradation of RhB and photocatalytic hydrogen production under visible-light irradiation. It has been found that the optimal photocatalyst (SCN/NiS-1) showed outstanding photocatalytic activity of removing 98.5% RhB within 15 min and 700.9 μmol‧g−1‧h−1 H2-evolving rate with 0.89 wt% sulfur doping and 1 wt% NiS loading, respectively, which were significantly higher than pristine g-C3N4. The enhanced photocatalytic activity of SCN/NiS-1 was due to its expanded light absorption and facilitated separation or transportation of photoinduced charge carriers under the synergistic function of S doping and NiS loading. A possible mechanism of SCN/NiS-x on the improvement of the photocatalytic performance of carbon nitride was proposed based on a series of characterization analyses. This work strengthens the idea that bulk and surface engineering simultaneously affect photocatalytic activity.

Constructing TiO2@Bi2O3 multi-heterojunction hollow structure for enhanced visible-light photocatalytic performance

Combining heterojunction with advanced structures is a promising tool to enhance the photoelectrochemical performance of semiconductor photocatalysts for environmental remediation. Herein, a novel multi-heterojunction TiO2@Bi2O3 (MHTB) hollow photocatalyst is successfully constructed by loading Bi2O3 nanoparticles on the surface of inner TiO2 and outside of TiO2 shell. Photoelectrochemical characterizations show that the formation of multiple heterojunctions at the TiO2@Bi2O3 interfaces facilitates faster separation and transfer of photoinduced charge carriers than that of conventionally reported p-n heterojunction photocatalysts. Because of the separated two layers of Bi2O3 and unique hollow structure, the photocatalytic performance of MHTB is significantly improved, leading to excellent photo-degradation rate constant (k = 0.0165 min−1) for the degradation of levofloxacin, which approaches 1.5-fold and 2.6-fold increase than that of TiO2@Bi2O3@TiO2 (n-p-n heterojunction) and TiO2@Bi2O3 (n-p heterojunction), respectively. Notably, the MHTB photocatalyst exhibits an excellent anti-interference capability for the interference of environmental factors. Moreover, the photocatalytic activity, crystal structure, and bonding energy of MHTB photocatalyst remain unchanged after being used several times, indicating an excellent stability. Therefore, this finding opens a new door to develop highly active photocatalysts with multiple heterojunctions for efficient pollutant removal and environmental remediation.

Polyaniline modified Cu2+-Bi2O3 nanoparticles: Preparation and photocatalytic activity for Rhodamine B degradation

Polyaniline-modified Cu2+-Bi2O3 nanocomposites were prepared and characterized for morphology, phase structure, elemental constitution, and optical properties by using relevant techniques like SEM, XRD, EDX, UVDRS, and PL, respectively. The photocatalytic tests for RhB removal demonstrated that heterostructured Cu2+-Bi2O3/polyaniline enabled the separation and transfer of photoinduced charge carriers, and the highest activity of 97.21% in 30 min was shown by the sample Cu2+-Bi2O3/polyaniline (5 wt %). Modification with polyaniline could efficiently enhance the catalytic activity of Bi2O3, and finally, a possible mechanism of degradation was presented.

Nitrogen-doped graphyne/BiOBr nanocomposites: In-situ sonochemical synthesis and boosted photocatalytic performance

In this study, a facile in-situ sonochemical synthesis process is developed to construct nitrogen-doped graphyne/BiOBr composites. Multiple techniques are implemented to characterize the structures, morphologies, electronic and optical properties, and photocatalytic activity of the as-prepared samples, including X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, Raman, and X-ray photoelectron spectroscopy, etc. The results indicate that the wrinkle-like layer structure of N-graphyne enwinds around the sheet structure of BiOBr. Compared to pristine BiOBr, N-graphyne/BiOBr composites present superior visible-light response, higher specific surface area, and more significant separation of photoinduced charge carriers verified by Brunauer-Emmett-Teller, UV–vis absorption spectroscopy, instantaneous photocurrent, electrochemical impedance spectroscopy, and photoluminescence, thus presenting more pronounced visible-light photocatalytic properties on N2 fixation and decomposition of pollutants. The optimal ratio of N-graphyne in N-graphyne/BiOBr composites is screened out for the photocatalytic decomposition of rhodamine B, levofloxacin, methylene blue, and nitrogen fixation under visible light illumination. Furthermore, the main active species are demonstrated as hole and O2– during photocatalytic degradation and the stable performance of is also observed for N-graphyne/BiOBr composites. The present research demonstrates that N-graphyne embellishment is an effective strategy to enhance the photocatalytic efficiency of BiOBr, which can be broadened as an excellent co-catalyst for decoration of other semiconductors.

Bi-functional Cu-TiO2/CuO photocatalyst for large-scale synergistic treatment of waste sewage containing organics and heavy metal ions

Numerous photocatalysts have been prepared for the photocatalysis of either organic pollutant degradation or Cr(VI) reduction. However, most of the inorganic and organic pollutants usually co-exist in industrial sewage. Simultaneous elimination of mixed inorganic and organic pollutants remains highly challenging. Herein, we report bi-functional Cu-TiO2/CuO photocatalysts by the in-situ doping and heterostructure engineering strategies for large-scale and highly enhanced synergistic photocatalytic elimination of organic pollutants and transitional metallic ions from waste sewage in one shot. Specifically, this bi-functional photocatalyst displays about 2.35 and 3.84 times higher photocatalytic Rhodamine B (RhB) degradation and Cr(VI) reduction rates in the solution with co-existing RhB and Cr(VI) than that in the single RhB or Cr(VI) pollutant solution, respectively. A highly boosted synergetic effect between photocatalytic dye molecule degradation and Cr(VI) reduction is revealed. The bi-functional photocatalyst also displays extraordinary activity and stability in large-scale photocatalytic elimination of mixed pollutants. Moreover, theoretical calculations demonstrate that Cu doping and heterostructure engineering give rise to the narrowed bandgap for enhanced light harvesting, the increased density of states for high charge carrier density, the delocalized electron for fast photoinduced charge carrier separation, and the profitable charge transfer between TiO2 and CuO, thus bringing about the efficient synergetic photocatalysis. The bi-functional photocatalyst concept reported in this study opens a new avenue to construct bi-functional photocatalysts for solar-to-fuel conversion and large-scale industrial waste water treatment and river purification.

In situ embedment of CoOx on g-C3N4 as Z scheme heterojunction for efficient photocatalytic degradation of methyl orange and phenol under visible light

A facile one-step pyrolysis method was reported to construct a Z-scheme CoOx/g-C3N4 heterostructures, which exhibit obviously enhanced visible light driven photocatalytic degradation of methyl orange and other organic pollutants. The samples were characterized by XRD,TEM, SEM, N2 adsorption-desorption, UV–vis DRS and XPS, the characterization results identified that the cobalt oxide clusters were embedded on g-C3N4 via the strong interface electronic interaction between cobalt and sp2-N of g-C3N4. Photoelectrochemical analysis revealed that the charge transfer and separation of CoOx/g-C3N4 heterostructure have been greatly improved. A plausible Z scheme photocatalytic mechanism was proposed and confirmed by the radical trapping experiment results. The significantly enhanced photocatalytic performance of CoOx/g-C3N4 heterostructures than g-C3N4 can be ascribed to the Z-Scheme charge transferring mode and improved separation of photo-induced charge carriers driven by inner electric field at the interface between CoOx and g-C3N4.