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Development of highly efficient and metal‐free photocatalysts for bacterial inactivation under natural light is a major challenge in photocatalytic antibiosis. Herein, we developed an acidizing solvent‐thermal approach for inserting a non‐conjugated ethylenediamine segment into the conjugated planes of 3,4,9,10‐perylene tetracarboxylic anhydride to generate a photocatalyst containing segregated π‐conjugation units (EDA‐PTCDA). Under natural light, EDA‐PTCDA achieved 99.9 % inactivation of Escherichia coli and Staphylococcus aureus (60 and 45 min), which is the highest efficiency among all the natural light antibacterial reports. The difference in the surface potential and excited charge density corroborated the possibility of a built‐in electron‐trap effect of the non‐conjugated segments of EDA‐PTCDA, thus forming a highly active EDA‐PTDA/bacteria interface. In addition, EDA‐PTCDA exhibited negligible toxicity and damage to normal tissue cells. This catalyst provides a new opportunity for photocatalytic antibiosis under natural light conditions. [ABSTRACT FROM AUTHOR]

Due to the low charge separation efficiency and high stability of the CO2 molecule, photoreduction of CO2 into a single multielectron product such as CH4 with a simultaneous high conversion rate and selectivity is challenging. Therefore, it is highly desirable to accelerate charge separation and transfer and provide an electron‐enriched catalyst surface for the deep reduction of CO2. Herein, a Pd/Cu2O/TiO2 ternary hybrid photocatalyst consisting of Pd nanoparticles (NPs) and Cu2O NPs‐decorated TiO2 nanosheets is rationally designed, and highly selective photocatalytic photoreduction of CO2 into CH4 is achieved. The Pd/Cu2O/TiO2 photocatalyst shows a high CH4 production rate of 42.8 μmol g−1 h−1 with an extremely high selectivity of 99.5%. This CH4 production rate is 61.1, 5.4, and 2.8 times higher than the bare TiO2, Cu2O/TiO2, and Pd/TiO2, respectively. In this Pd/Cu2O/TiO2 hybrid, a consecutive multistep charge transfer is steered between the Cu2O/TiO2 heterojunction and Pd, ensures accelerated charge separation and transfer, and leads to the formation of a spatially separated electron‐enriched surface (Pd) and hole‐enriched surface (Cu2O). This spatially oriented charge transfer and the charge‐enriched catalyst surface synergistically contribute to the simultaneous high conversion rate and selectivity of CH4. [ABSTRACT FROM AUTHOR]

Solar-to-hydrogen conversion from water splitting have received a great of interest because it can alleviate the serious environmental pollution and energy crisis. The KNbO3 photocatalyst with high conduction band and excellent anticorrosion has been reported for water splitting, but the large band gap and low separation efficiency of electron–hole pairs restrict its photocatalytic activity. In this work, the CoO/KNbO3 p-n heterojunction photocatalysts were prepared via a hydrothermal and calcination method, which exhibits excellent photocatalytic for H2 production with high rates at 144.36 μmol h−1 g−1 under simulated sunlight and 76.78 μmol h−1 g−1 under visible light irradiation (λ > 420 nm). The enhanced H2 production was ascribed to the improvement of visible light absorption and the efficient charge separation after the formation of CoO/KNbO3 p-n heterojunction, which was evidenced by the UV–vis diffuse spectra and transient photocurrent. Finally, a possible mechanism was proposed for the CoO/KNbO3 p-n heterojunction photocatalysts toward the photocatalytic activity of H2 production. This kind of CoO/KNbO3 p-n heterojunction photocatalysts can provide a reference for developing high-efficiency KNbO3-based photocatalysts. [ABSTRACT FROM AUTHOR]

I–III–VI quantum dots (QDs) play an important role in visible-light-driven photocatalysis due to their unique optical properties and widely tunable bandgap. However, these materials suffer from rich defect states and high charge carrier recombination. In this work, a facile mixed-ligand method was developed for the manipulation of the optical and photocatalytic properties of multinary Ag–In–Zn–S QDs by introducing 3-mecaptopropionic acid (MPA) into the l-cysteine (Cys) capped QDs system during synthesis. The effect and mechanism of MPA addition was systematically investigated. With the increase of MPA/Cys, the photoluminescence (PL) quantum yield (QY) of the QDs shows an obvious increase at the first stage (MPA/Cys < 5:5), whereas the particle size and UV–Vis absorption remain almost unchanged. Photocatalytic properties of QDs shows similar trend as PL QY with the increase of MPA/Cys, where the hydrogen production rate was doubled with MPA/Cys = 5:5. With ascorbic acid (AA) as the sacrificial reagent, the MPA/Cys capped QDs gave a hydrogen production rate as high as 6.64 mmol g−1 h−1, which is comparable to the state-of-the-art results but without any cocatalyst, indicating the fascination of the simple mixed-ligand method. Further mechanism study indicates that the introduced MPA resulted in dramatic increase of the PL lifetime and the reduction of nonradiative decay, which can be ascribed to the strong passivation effect of MPA. The MPA/Cys capped QDs also show compressed charge recombination as indicated in electrochemical impedance spectra, slightly more negative ζ-potential and reduced hydrated particle radius, which may also contribute to the improved charge transfer for photocatalysis. Our method provides a super simple strategy for the defect manipulation of the Ag–In–Zn–S QDs without the sacrifice of charge transfer, which could be a useful guideline for efficient QDs-based visible-active photocatalysts. Mixed-ligand-modified Ag–In–Zn–S quantum dots with improved hydrogen production were prepared. [ABSTRACT FROM AUTHOR]

We have successfully synthesized the composites of two-phase g-C3N4 heterojunction photocatalysts by one-step method. And the reduced graphene oxide/two-phase g-C3N4 heterojunction photocatalyst was fabricated via a facile hydrothermal reduction method. The characterization results indicated that the two-phase g-C3N4 was integrated closely, and the common phenomenon of agglomeration for g-C3N4 was significantly reduced. Moreover, the oxidized graphene was reduced successfully in the composites and the graphene was overlaid on the surface or the interlayers of g-C3N4 heterojunction composite uniformly. In addition, we have carried out the photocatalytic activity experiments by H2 evolution and rhodamine B removal, tetracycline removal under the visible light irradiation. The results revealed that the composite has improved the separation efficiency a lot than the pure photocatalyst. The photocurrent test demonstrated that the recombination of electrons and holes were efficiently inhibited as well as enhanced the photocatalytic activity. The 0.4% rGO loaded samples, 0.4% rGOCN2, own the best performance. Its rate of H2 evolution was 15 times as high as that of the pure g-C3N4. [ABSTRACT FROM AUTHOR]

In this paper, LaFeO nanoparticles were used as a visible light photocatalyst for efficient removal of 2,4-dichlorophenoxyacetic acid (2,4-D) with the assist of ozone. The pseudo-first-order kinetic rate constants of degrading 2,4-D removal in 60-PO/Vis in 1 h was 5.72 times as great as the sum of that when using LFO/O/Vis and 60-Oz/Vis at the best concentration of ozone (60 mL/min). This improvement was attributed to the efficient synergistic effect between photocatalysis and ozonation triggered by LaFeO. In PO/Vis, ozone facilitates the photo-generated electrons trapping and improves separation efficiency of photo-generated charges, which enhanced the yield of hydroxyl radical, so as to the degradation efficiency of organic pollutants. In addition, the effects of ozone concentrations on the photocatalytic ozonation processes were also studied. Moreover, we demonstrated the high stability and reusability of LaFeO photocatalyst in photocatalytic ozonation process by circle experiment. Graphical Abstract: Schematic illustration of the reaction mechanism of enhanced photocatalytic ozonation of 2,4-D by LaFeO under visible light. [ABSTRACT FROM AUTHOR]

The photocatalytic technology as a kind of green and potential technology has been paid more and more attention in ever-increasing environmental pollution and energy shortage. In this study, a practical strategy is proposed to facilitate effectively the separation of photogenerated electrons and holes by addition of graphene oxide in Ag3PO4 and Bi2WO6 nanocrystals semiconductor composites. Compared with GO-single component, the three-component RGO-Ag3PO4/Bi2WO6 composites exhibited improved photocatalytic activity with a degradation rate that reached up to 91% for tetracycline (TC) by visible light irradiation. Graphene oxide served as an electronic conduction medium to effectively transfer the photogenerated electrons from the conduction band of Bi2WO6 to the valence band of Ag3PO4; the all-solid-state Z-Scheme photocatalytic mechanism was proposed. Our work provides an effective method for development of pragmatic photocatalysts in the present environmental pollution, energy problems and other related fields. The Ag3PO4 and Bi2WO6 semiconductors were used to construct an all-solid-state Z-scheme-like composite photocatalyst by simple synthesis. The reduced graphene oxide was used as a solid-state medium to efficiently transport photogenerated electrons from the conduction band of Bi2WO6 to the valence band of Ag3PO4. This Z-scheme-like system efficiently realizes antibiotic degradation. [ABSTRACT FROM AUTHOR]

The development of Z-scheme heterojunction photocatalytic systems is a promising strategy to produce hydrogen and for pollutant degradation. In this study, the direct Z-scheme CdS/Bi4V2O11 photocatalysts were synthesized via a two-step solvothermal method. The photocatalytic properties of the samples were measured by ciprofloxacin (CIP), tetracycline (TC) and rhodamine B (RhB) degradation under visible light (λ ＞ 420 nm). In addition, a probable reaction mechanism for organic pollutants over CdS/Bi4V2O11 photocatalysts was also proposed based on the analysis of electron spin resonance (ESR) and active species capture experiments. The enhanced photocatalytic activity of CdS/Bi4V2O11 photocatalysts was ascribed to the efficient electron transfer of direct Z-scheme CdS/Bi4V2O11 photocatalysts. [ABSTRACT FROM AUTHOR]

Spatial separation of photogenerated electron-hole pairs is one of the most important factors that determine the efficiency of a photocatalyst. It is well acknowledged that the fabrication of heterogeneous photocatalysts with two different inorganic semiconductors is a good strategy to effectively improve the charge separation of electrons and holes. This study describes a novel visible light-induced g-C3N4/Bi3TaO7 composite photocatalyst with superior photocatalytic properties toward the degradation of tetracycline (TC) by visible light irradiation. The formation of heterojunctions significantly improves the separation efficiency of photogenerated carriers, which is confirmed by the photocurrent density and electrochemical impedance spectroscopy. Electron spin resonance examination and trapping experiments confirm that the photoinduced active species (ṖOH and ṖO2−) are responsible for the degradation of tetracycline. Based on the experimental results, a possible Z-scheme system reaction mechanism for the g-C3N4/Bi3TaO7 composite towards the degradation of TC under visible light was proposed. [ABSTRACT FROM AUTHOR]

A direct CdS/BiOI Z-scheme heterojunction has been successfully synthesized via a hydrothermal method for the first time. The photocatalytic performances of as-prepared samples were evaluated by rhodamine B degradation under visible light (λ ＞ 420 nm) irradiation. The phase structures, morphologies and optical properties of the obtained samples were investigated by several characterization tools such as XRD, SEM, TEM, HRTEM, STEM, XPS, and UV-vis, photocurrent and PL spectroscopy. The results revealed that the CdS/BiOI Z-scheme heterojunction exhibited much higher photocatalytic activity than pure BiOI and CdS, and the sample of CdS/BiOI-2 showed the best activity among all the heterostructure photocatalysts. In addition, the ESR spectrum indicated that ṖO2− and e− were the main active species for the photocatalytic degradation of RhB in our experiment. [ABSTRACT FROM AUTHOR]

Ternary p-n heterostructures photocatalysts of AgCl/Ag 2 O/NaTaO 3 were synthesized via a simple method and the crystal structure characterized by X-ray diffraction (XRD). The morphology of the photocatalysts were characterized by scanning electron microscopy and transmission electron microscopy. The composition of the photocatalysts was studied by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscope. The photocatalytic activity of the AgCl/Ag 2 O/NaTaO 3 photocatalysts was evaluated using the degradation of Rhodamine B. The AgCl/Ag 2 O/NaTaO 3 photocatalysts showed higher visible light activity than the pure NaTaO 3 and Ag 2 O/NaTaO 3 photocatalysts. Additionally, the photocatalytic mechanism was that the rapidly separation of photoinduced electrons and holes resulted the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

Well-defined m -BiVO 4 dendrites have been synthesized using a simple hydrothermal method without adding organic surfactant. A series of time-dependent experiments were conducted to investigate the shape formation mechanism of the m -BiVO 4 dendrites. Furthermore, the corresponding growth mechanism which involved the Ostwald ripening process has been discussed. The m -BiVO 4 dendrites showed great enhanced activity in the visible-light photocatalytic degradation of Rhodamine B (RhB) solution which might be attributed to the special morphology. [ABSTRACT FROM AUTHOR]

Visible-light-response porous carbon sphere/InOOH nanocomposites were synthesized through a facile hydrothermal process. The grain size of the crystalline InOOH is estimated around 14 nm, and the nanocomposites show a size range from 100 to 200 nm. The as-prepared nanocomposites possess a porous structure and a specific surface area of 45 mg. A possible in situ formation process was proposed after conducting a series of contrast experiments. Carbon spheres (CSs) were suggested to act as spherical templates and reducing reagents during the synthesis process of nanocomposites. The whole process involves the hydrolysis of indium ions, the redox reactions on surfaces groups of the CSs, and the dehydration of indium hydroxide. UV-Vis diffuse reflectance spectrum revealed a red shift of light absorption of the nanocomposites to about 600 nm compared with pure InOOH. The photocatalytic degradation for methylene blue was performed under visible light irradiation, 90 % of methylene blue was degraded after reacting for 6 h. We propose that the red shift was attributed to the interaction between carbon sphere and InOOH, and the CSs may act as photosensitizers. [ABSTRACT FROM AUTHOR]

In this work, n-type porous graphite-like C3N4 (denoted as p-g-C3N4) was fabricated and modified with p-type nanostructured BiOI to form a novel BiOI/p-g-C3N4 p–n heterojunction photocatalyst for the efficient photocatalytic degradation of methylene blue (MB). The results show that the BiOI/p-g-C3N4 heterojunction photocatalyst exhibits superior photocatalytic activity compared to pure BiOI and p-g-C3N4. The visible-light photocatalytic activity enhancement of BiOI/p-g-C3N4 heterostructures could be attributed to its strong absorption in the visible region and low recombination rate of the electron–hole pairs because of the heterojunction formed between BiOI and p-g-C3N4. It was also found that the photodegradation of MB molecules is mainly attributed to the oxidation action of the generated O2Ṗ− radicals and partly to the action of hvb+via direct hole oxidation process. [ABSTRACT FROM AUTHOR]

Graphite-like carbon nitride (g-C 3 N 4) has been regarded as a promising photocatalyst for solar-to-chemical conversion. Nevertheless, the narrow absorption of light extremely limited its photocatalytic performance under near-infrared (NIR) irradiation. Herein, the Cu 7. 2 S 4 with outstanding NIR absorption was successfully introduced to g-C 3 N 4 nanosheets through a simple in-situ growth procedure. As expected, the constructed Cu 7.2 S 4 /g-C 3 N 4 (CSCN) photocatalysts exhibit superior H 2 production activity of 82 μmol g−1 h−1 under NIR light irradiation (λ > 800 nm), which outperforms currently reported g–C 3 N 4 –based NIR-driven H 2 production systems. Especially, the optimal sample CSCN-5 displays a robust activity of 66 μmol g−1 h−1 at λ = 850 nm monochromatic light irradiation. The excellent photocatalytic performance is linked to the extended optical absorption as well as the efficient separation efficiency of photoinduced carriers, which are evidenced by the UV-visible absorption spectroscopy and photoelectrochemical test. This work provides an effective approach for constructing a Cu 7.2 S 4 /g-C 3 N 4 photocatalytic system for the transformation of NIR solar energy into hydrogen. The novel NIR-driven Cu 7. 2 S 4 /g-C 3 N 4 composite photocatalyst was constructed through a convenient in situ growth process. As expected, the outstanding photocatalytic H 2 yield was 82 μmol g−1 h−1 under the irradiation of NIR light (λ > 800 nm), which outperforms currently reported g–C 3 N 4 –based NIR-driven H 2 production systems. More significantly, the sample CSCN-5 shows an optimum activity (66 μmol g−1 h−1) under λ = 850 nm monochromatic light irradiation. This work provides a feasible approach for achieving g–C 3 N 4 –based photocatalyst NIR-induced superior solar-to-chemical conversion. [Display omitted] • Cu 7·2 S 4 modified g-C 3 N 4 is prepared by a facile hydrothermal treatment method. • The Cu 7·2 S 4 /g-C 3 N 4 composites show a superior optical adsorption from visible to NIR. • The Cu 7·2 S 4 /g–C 3 N 4 –5 composite exhibits excellent HER of 82 μmol g−1 h−1 (λ > 800 nm). • The HER of Cu 7·2 S 4 /g–C 3 N 4 –5 shows no obvious change after 4 runs within 20 h. [ABSTRACT FROM AUTHOR]

In this paper, octahedral K 2 Ta 2 O 6 nanocrystals have been synthesized by a single-step hydrothermal method. Then the visible-light-driven plasmonic Ag–K 2 Ta 2 O 6 nanocomposite photocatalysts are prepared by a photochemical reduction process. The product was characterized using various techniques, such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), UV–visible diffuse-reflectance spectroscopy (DRS). The results show that the Ag nanoparticles are uniformly loaded on the surface of the K 2 Ta 2 O 6 . The prepared Ag–K 2 Ta 2 O 6 exhibits an efficient photocatalytic activity for degradation of tetracycline (TC) under visible-light irradiation and shows good repeatability and stability. In particular, the highest photocatalytic activity at the nominal atomic ratio of silver to tantalum as 3%, which is more than 3 times that of pure K 2 Ta 2 O 6 . [ABSTRACT FROM AUTHOR]

[Display omitted] Photo-chemical conversion of CO 2 into solar fuels by photocatalysts is a promising and sustainable strategy in response to the ever-increasing environmental problems and imminent energy crisis. However, it is unavoidably impeded by the insufficient active site, undesirable inert charge transfer and fast recombination of photogenerated charge carriers on semiconductor photocatalysts. In this work, all these challenges are overcome by construction of a novel defect-engineered Z-scheme hybrid photocatalyst, which is comprised of three-dimensional (3D) BiOBr nanoflowers assembled by nanosheets with abundant oxygen vacancies (BiOBr-V O) and two-dimensional (2D) HNb 3 O 8 nanosheets (HNb 3 O 8 NS). The special 3D-2D architecture structure is beneficial to preventing photocatalyst stacking and providing more active sites, and the introduced oxygen vacancies not only broaden the light absorption range but also enhance the electrical conductivity. More importantly, the constructed Z-scheme photocatalytic system could accelerate the charge carriers transfer and separation. As a result, the optimal BiOBr-V O /HNb 3 O 8 NS (50%-BiOBr-V O /HNb 3 O 8 NS) shows a high CO production yield of 164.6 μmol·g−1 with the selectivity achieves to 98.7% in a mild gas-solid system using water as electron donors. Moreover, the BiOBr-V O /HNb 3 O 8 NS photocatalyst keeps high photocatalytic activity after five cycles under the identical experimental conditions, demonstrating its excellent long-term durability. This work provided an original strategy to design a new hybrid structure photocatalyst involved V O s, thus guiding a new way to further enhance CO 2 reduction activity of photocatalyst. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for hydrogen production represents an ideal pathway for solar energy harvesting and conversion, for which narrow bandgap multinary sulfides play an important role. Here, series of Zn–AgIn 5 S 8 /g-C3N4 0D/2D nanocomposites were prepared by in-situ growth of the Zn–AgIn 5 S 8 quantum dots (QDs) on g-C3N4 nanosheets for improved charge separation. To our surprise, rather than a photoactive component, here g-C3N4 nanosheets act as a charge transfer mediator, where only a relatively low ratio is required. The as-fabricated Zn–AgIn 5 S 8 /g-C3N4 nanocomposites were systematically studied. When the mass ratio of g-C3N4 was 10%, the hydrogen production rate was maximized, which was 1.39 times higher than pure Zn–AgIn 5 S 8 QDs and 138.6 times higher than g-C3N4. The enhanced photocatalytic activity of the Zn–AgIn 5 S 8 /g-C3N4 nanocomposites is attributed to the intimate interface contact, which results in the effective separation and transfer of the photogenerated charge carriers as proved by the PL lifetime, transient photocurrent and electrochemical impedance spectra measurements. The Zn–AgIn 5 S 8 /g-C3N4 nanocomposites also exhibit excellent cycle stability. A plausible mechanism was proposed for the 0D/2D Zn–AgIn 5 S 8 /g-C3N4 composite photocatalysts. This work provides a relatively simple method for constructing high-quality 0D/2D heterostructure of QDs/nanosheets, as well as new insight for the efficiency improvement of narrow-bandgap sulfide photocatalysts. Image 1 • 0D/2D Zn–AgIn 5 S 8 /g-C 3 N 4 were prepared by a simple in-situ growth method. • Zn–AgIn 5 S 8 /g-C 3 N 4 exhibited higher H 2 production rate and longer carrier lifetime. • The g-C 3 N 4 nanosheets act as the hole transfer mediator instead of light absorber. [ABSTRACT FROM AUTHOR]

In this paper, g-C 3 N 4 /KNbO 3 heterojunction composites were prepared and used to water splitting for hydrogen production under simulated sunlight. The morphology and structure of the composites were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-Ray spectroscopy and high resolution transmission electron microscopy. The g-C 3 N 4 /KNbO 3 composites exhibited the better photocatalytic performance for water splitting more than 2 and 1.8 times of the pure g-C 3 N 4 and KNbO 3 . Meanwhile, the Pt nanoparticles as a co-catalyst were deposited on the surface of g-C 3 N 4 /KNbO 3 as Pt-g-C 3 N 4 /KNbO 3 composites for water splitting which enhanced photocatalytic properties almost 74 and 14 times than that of Pt-KNbO 3 and Pt-g-C 3 N 4 . Such a significant improvement of the photocatalytic activity was mainly ascribed to the photoinduced electron-holes in the interface of g-C 3 N 4 /KNbO 3 composites rapid separation and the co-catalysis effect of Pt nanoparticles. These present study work may provide a useful method for water splitting using an effective composites photocatalysts. [ABSTRACT FROM AUTHOR]

A novel efficient magnetic oxidation-reduction like-Z-scheme structure photocatalyst composed of g-C 3 N 4 , CdS and the oxidation-reduction mediators of Fe 3 O 4 is successfully synthesized by heat treatment methods. The like-Z-scheme CdS/Fe 3 O 4 /g-C 3 N 4 photocatalyst exhibits universal degradation property on removing kinds of antibiotics, and the photocatalytic activity is better than that of CdS/g-C 3 N 4 and pure g-C 3 N 4 . The excellent photocatalytic performance is originated from the unique like-Z-scheme structure and oxidation–reduction function of Fe 3 O 4 , which effectively separates the hole-electron and sufficiently utilizes the photogenerated carriers for generating more active radicals. The results showed that when the content of Fe 3 O 4 is 10%, the CdS/Fe 3 O 4 /g-C 3 N 4 exhibited superior activity. The best degradation rate constant K in the like-Z-scheme photocatalyst is approximately 26 times of pure g-C 3 N 4 . The important role of Fe 3 O 4 and the photocatalytic mechanism are also discussed in detail. This work not only puts forward a novel design idea of the like-Z-scheme material, but also is expected to be widely applied to the universal removal of kinds of antibiotics according to the practical requirement. [ABSTRACT FROM AUTHOR]

Unraveling how mid-gap state energy level of graphitic carbon nitride (g-C 3 N 4) promote near-infrared (NIR) driven photochemical energy conversion at the molecular level remains a grand challenge. Here, we report a series of S double-site-doped ultrathin g-C 3 N 4 nanosheets (SUCN) with adjustable intermediate band gap benefits from light response over NIR region. The SUCN produced after optimizing S double-site doping can effectively generate hydrogen (H 2) under NIR-light irradiation. The highest H 2 generation rate achieved was respectively 9.35 and 17.46 μmol g−1 h−1 under λ = 765 and λ > 800 nm, which is firstly expended photocatalytic activity of S-doped g-C 3 N 4 to NIR region beyond λ > 765 nm. We proposed a molecular-level method, i.e., the localized oxidation state of proton acceptor triethanolamine (TEOA) in the mid-gap state to ensure the NIR-driven H 2 generating behavior. [Display omitted] • g-C 3 N 4 was doped with S atoms at a specific site of the triazine skeleton. • S doping provides an adjustable intermediate band gap of g-C 3 N 4. • The 0.36-SUCN obtained 43 times higher PHE than g-C 3 N 4. • The S-doped g-C 3 N 4 firstly realized PHE in the near-infrared region. • The NIR-driven H 2 generation was firstly demonstrated by a molecular-level method. [ABSTRACT FROM AUTHOR]

The increasing environmental deterioration poses a severe threat to human health and ecosystems, and the photocatalytic degradation of environmental pollutions has gained intensive interest in recent years. In this study, we prepared a novel ternary Ag 3 PO 4 /g-C 3 N 4 /Znln 2 S 4 (ACZ) photocatalyst by a hydrothermal method and deposition-precipitation technique. The ACZ composites exhibited much higher photocatalytic activities for the degradation of tetracycline (TC) than the sum of g-C 3 N 4 , Znln 2 S 4 , Ag 3 PO 4 /g-C 3 N 4 , Ag 3 PO 4 /Znln 2 S 4 or g-C 3 N 4 /Znln 2 S 4 under visible light irradiation (λ > 420 nm) in the photocatalytic tests. Especially, when the content of Ag 3 PO 4 reached 3 wt% (ACZ-3), the ACZ-3 displayed the highest photocatalytic activity, which can degrade 83% TC (20 mg/L) within 60 min. The improvement in photocatalytic performance of the ternary photocatalyst is mainly attributed to the extended absorption in the visible light region and the effective separation of photogenerated electron-hole pairs between the Ag 3 PO 4 and g-C 3 N 4 /Znln 2 S 4 . [ABSTRACT FROM AUTHOR]

The development of efficient visible-light-driven photocatalysts for water splitting has drawn much attention. Herein, we demonstrated a novel H 2 -producing photocatalytic system that employed nitrogen doped graphene quantum dots (NGQDs)-ZnNb 2 O 6 /g-C 3 N 4 heterostructures as the hydrogen evolving catalysts. The as-prepared NGQDs-ZnNb 2 O 6 /g-C 3 N 4 heterostructures were favorable for light harvesting and charge separation, and showed highly efficient photocatalytic performance for water splitting into hydrogen. Results showed that both the ZnNb 2 O 6 /g-C 3 N 4 (Zn/CN) mole ratio and the amount of NGQDs displayed important influence for H 2 production. Moreover, the optimum synthesis conditions of the Zn/CN mole ratio (1/7) and the amount of NGQDs (5%) were both obtained, and the corresponding 5%NGQDs-Zn/7CN sample performed a much higher hydrogen-evolution rate of 340.9 μmol h −1 g −1 . By the further studies, the enhanced photocatalytic activity could be ascribed to the crucial roles of NGQDs and heterojunction photocatalytic system, which resulted in an efficient charge separation and the largely enhanced photocatalytic activity. Meanwhile, the possible photocatalytic mechanism of NGQDs-ZnNb 2 O 6 /g-C 3 N 4 was also proposed. We envision that this work creates new opportunities for constructing and designing efficient visible-light-driven photocatalysts for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

In this work, novel CuS/g-C 3 N 4 composite photocatalysts were successfully prepared via a simple in-situ growth method. CuS nanoparticles, with an average diameter of ca.10 nm, were well dispersed on the surface of g-C 3 N 4 , revealing that g-C 3 N 4 nanosheets were promising support for in-situ growth of nanosize materials. The CuS/g-C 3 N 4 composites exhibited highly enhanced visible light photocatalytic H 2 evolution from water-splitting compared to pure g-C 3 N 4 . The optimum photocatalytic activity of 2 wt% CuS/g-C 3 N 4 composite photocatalytic H 2 evolution was about 13.76 times higher than pure g-C 3 N 4 . The enhanced photocatalytic activity is attributed to the interfacial charge transfer (IFCT). In this system, electrons in the valence band (VB) of g-C 3 N 4 can transfer directly to CuS clusters, causing the reduction of partial CuS to Cu 2 S, which can act as an electron sink and co-catalyst to promote the separation and transfer of photo-generated electrons. The accumulated photoinduced electrons in CuS/Cu 2 S clusters could effectively reduce H + to produce H 2 . This work provides a possibility for constructing low-cost CuS as a substitute for noble metals in the photocatalytic production of H 2 via a facile method based on g-C 3 N 4 . [ABSTRACT FROM AUTHOR]

Novel p-n junction photocatalysts nitrogen doped graphene quantum dots (NGQDs)-BiOI/MnNb 2 O 6 have been prepared via hydrothermal method for the environmental remediation. The photocatalytic activity of as-prepared photocatalysts was evaluated by the degradation of different antibiotics such as tetracycline (TC), oxytetracyline, ciprofloxacin and doxycycline. Compared with single MnNb 2 O 6 and BiOI, the hybrid materials (NGQDs-BiOI/MnNb 2 O 6 ) could significantly enhance photocatalytic activity. Meanwhile, both the BiOI/MnNb 2 O 6 ratio (Bi/Mn ratio) and the amount of NGQDs displayed important influence on the antibiotics degradation. In addition, the 5%NGQDs-Bi/Mn sample performed the optimum photocatalytic degradation toward TC (87.2%) within 60 min. By further studies based on the electron spin resonance (ESR) and active species trapping experiments, this enhanced photocatalytic property could be ascribed to high charge carrier mobility of NGQDs and the p-n junction photocatalytic systems, which greatly promoted efficient separation of charge carriers. [ABSTRACT FROM AUTHOR]

Two-dimensional g-C 3 N 4 /Bi 2 WO 6 heterojunction photocatalysts have been successfully synthesized by a multi-step method. Based on the structure and morphology characterization, the as-prepared photocatalysts exhibited a nanosheet/nanosheet hybrid structure, which could provide a large heterogeneous surface area, increase the transmission route of photo-induced carriers and then suppress the charge recombination. To investigate the practical photocatalytic performance for water purification of these heterojunction photocatalysts, organic dyes such as Rhodamine B (RhB) and antibiotics including tetracycline (TC) and ciprofloxacin (CIP) have been selected as the target pollution under visible-light irradiation. The optimum photocatalyst (the weight ratio of g-C 3 N 4 to Bi 2 WO 6 is 1:0.67) was more than three times and two times than pure g-C 3 N 4 and Bi 2 WO 6 , respectively. The enhanced photocatalytic activities of g-C 3 N 4 /Bi 2 WO 6 heterojunction photocatalysts might be ascribed to the two-dimensional structure. In combination of the experiment results, the possible photo-induced charge transfer route has been detailed illustrated. [ABSTRACT FROM AUTHOR]

Ag quantum dots/g-C 3 N 4 (Ag QDs/g-C 3 N 4 ) photocatalysts were directly obtained via a novel one-step method. The photocatalysts were composed of Ag quantum dots with an average diameter of ca.5 nm, which were dispersed uniformly on the surface of g-C 3 N 4 nanosheets. By using methanol as sacrificial reagent, the Ag QDs/g-C 3 N 4 photocatalysts exhibited higher photoactivity for hydrogen production than the AX = 0 photocatalyst under visible-light irradiation (λ > 420 nm). Among various photocatalysts prepared, the AX = 0.5% photocatalyst showed maximum hydrogen production efficiency, which was enhanced by 4.6 times compared to AX = 0 photocatalyst. Our findings demonstrated that the coupled Ag QDs could enhance the visible light absorption and serve as g-C 3 N 4 electron acceptor for effective charge separation, and further increased it’s photocatalytic activity. [ABSTRACT FROM AUTHOR]

The photocatalytic technology provides a straightforward and effective strategy for the ever-increasing environmental and energy concerns. In this study, a practical strategy is proposed to facilitate the separation of e-h pairs and enhance the photostability in a semiconductor by the use of a Schottky junction in a noble metal-CQDs-semiconductor stack structure (CQDs, carbon quantum dots). Different characterization techniques were used to investigate the structural and optical properties of the synthesized samples. Importantly, due to the photoinduced electron transfer and upconverison luminescence properties of CQDs, the CQDs/Ag/Ag 2 O ternary photocatalysts exhibit excellent photocatalytic activity and operational stability in full-spectrum. Furthermore, Ag nanoparticles supported on an ultrathin CQDs layer encapsulating Ag 2 O octahedral crystal lead to the highest photocatalytic activity by the synergetic catalytic effect of interfacial modification and vectorial charge-transfer channel design. Our works provide an invaluable methodology for the development of practical photocatalysts in current environmental pollution, energy issues and other related areas. [ABSTRACT FROM AUTHOR]

The removal of pollutant using photocatalysis technology has received much attention due to the increasing serious environmental contamination. In this study, novel Nb 2 O 5 /g-C 3 N 4 heterojunctions were fabricated via a facile one-step heating strategy for the first time. Compared to pure g-C 3 N 4 and Nb 2 O 5 , the as-prepared Nb 2 O 5 /g-C 3 N 4 samples exhibited remarkably enhancing photocatalytic activity for degradation of tetracycline hydrochloride (TC-HCl) both under visible and simulated solar light irradiation. It was found that the 3% Nb 2 O 5 content of heterojunction (3%NO/CN) showed the highest photocatalytic efficiency for TC-HCl degradation, which is about 2.9-fold and 2.4-fold higher than that of pristine g-C 3 N 4 under visible and simulated solar light irradiation, respectively. In addition, the 3%NO/CN sample not only displayed excellent photocatalytic recyclability, but also can efficiently remove TC-HCl even under strong acidic condition (pH = 1). Moreover, the 3%NO/CN heterojunction also exhibited dramatically enhancement of photocatalytic activity for degradation of other fluoroquinolones antibiotic, such as ciprofloxacin (CIP) and levofloxacin (LEV). The highly enhancing photoactivity was attributed to the formation of a heterojunction between g-C 3 N 4 and Nb 2 O 5 , which could greatly suppresses the photogenerated electron–hole pair’s recombination. The active species trapping and ESR experiments indicated that superoxide radicals and holes are the major active species in which contributing to the photocatalytic process. This work will bring about potential application in treatment of antibiotic pollutant and solar energy conversion. [ABSTRACT FROM AUTHOR]

A novel CdS/Bi 2 MoO 6 heterojunction photocatalysts were successfully prepared via two-step hydrothermal methods. The prepared samples were characterized by various physicochemical techniques, such as XRD, SEM, TEM, HRTEM, XPS, UV–vis and PL. The obtained samples exhibited highly photocatalytic activity toward the degradation of the different kinds of organic dyes and tetracycline in aqueous solution under visible light irradiation ( λ > 420 nm). The optimum photocatalytic efficiency of CdS-2 sample for the degradation rhodamine B (RhB) was about 25.3 and 3.7 times higher than that of individual CdS and Bi 2 MoO 6 , respectively. In addition, the possible photocatalytic mechanism was analyzed by different active species trapping experiments. The results indicated that the h + and O 2 − were the main active species for the photocatalytic degradation of RhB. Moreover, the prepared sample shows good stability and recyclability properties which are beneficial for its practical application. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoS 2 and functionalized CDs guided the synergistic electron/hole extraction. • H 2 production rate of MoS 2 /AIZS/fCDs reaches 8.40 mmol·g−1·h−1, much superior to MoS 2 or fCDs. • Transient photovoltage spectroscopy directly proves the electron/hole extraction kinetics. • The apparent reaction kinetics analysis indicates a Volmer-Tafel process for H 2 evolution. Narrow-bandgap semiconductors play a key role in visible-light photocatalysis for solar energy conversion, where the severe charge trapping and recombination have been the main issues hindering the activity improvement. Here, MoS 2 nanosheets and ferrocene-functionalized carbon dots (fCDs) were loaded on Ag-In-Zn-S quantum dots (AIZS QDs) to form ternary composite photocatalysts towards efficient electron/hole co-extraction and profound kinetics understanding of the related processes. The optimal hydrogen production rate of MoS 2 /AIZS/fCDs reached 8.52 mmol g−1h−1, which is dramatically higher than AIZS QDs (17.67 times), indicating the synergistic effect of electron/hole co-extraction compared to AIZS/fCDs (4.67 times) and AIZS/MoS 2 (6.16 times). Transient photovoltage spectroscopy tests and the apparent kinetics analysis were carried out in terms of hydrogen production rate vs. effective surface charge carriers in the cases of pure QDs, hole extraction (binary AIZS/fCDs) and electron/hole coextraction, which indicated the hydrogen evolution reaction on the composites proceeds via the electrocatalysis based Volmer-Tafel process, involving the combination of two H* atoms to H 2. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) CdSe exhibits relatively high photocatalytic abilities for its unique properties, but the aggregation and photocorrosion have blocked its further application. Therefore, for arriving at a solution, alkaline earth metal ions (M = Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ ) and reduced graphene oxide (rGO) are chosen to fabricated new QDs CdSe-based photocatalytic systems. In this paper, M@CdSe/rGO composites have been synthesized via a facile one-step hydrothermal approach, during which the formation of M doped CdSe crystallization and GO reduction occur simultaneously. The obtained photocatalysts demonstrates synergistically enhanced visible light photocatalytic activity and stability toward photodegrading tetracycline hydrochloride (TC-HCl) solution, especially the introduction of 6 mol% Ca 2+ and 5 wt% GO on QDs CdSe resulted in 85.6% degradation of 15 mg/L TC-HCl in 1 h with 0.5 g/L catalyst. Furthermore, the photodegradation mechanism was systematically investigated by active species trapping experiment. It revealed that h + was the major active species in the destructions process. And the possible process of charge transfer for Ca 2+ @CdSe/rGO nanocomposite was proposed based on the experimental results. [ABSTRACT FROM AUTHOR]

Highly efficient visible-light-driven Ag 3 PO 4 /WO 3 photocatalysts with different mole fractions of Ag 3 PO 4 nanocrystals have been synthesized via an in situ precipitation method. Characterization results showed the in situ growth of finely distributed Ag 3 PO 4 nanocrystals on the surface of the WO 3 nanosheets. Under visible light irradiation, the Ag 3 PO 4 /WO 3 photocatalysts exhibited enhanced photocatalytic activity compared with bare Ag 3 PO 4 or WO 3 for the degradation of methyl blue, and the highest activity was reached by the Ag 3 PO 4 /WO 3 hybrid photocatalyst with 20 at% of Ag 3 PO 4 . The observed improvement in photocatalytic activity is associated with the extended absorption in the visible light region resulting from the attached Ag 3 PO 4 nanocrystals, and the effective separation of photo-induced carriers at the Ag 3 PO 4 /WO 3 interfaces. In addition, on the basis of the quenching effects of different scavengers and estimated energy band positions, the mechanism of enhanced photocatalytic activity is proposed. [ABSTRACT FROM AUTHOR]

Single-crystalline AgIn(MoO 4 ) 2 nanosheets have been successfully fabricated by facile hydrothermal method without any surfactants. Subsequently, Ag/AgBr-grafted AgIn(MoO 4 ) 2 nanosheets were synthesized by the in situ photoreduction of AgBr/AgIn(MoO 4 ) 2 composites prepared by a deposition–precipitation method. Under visible light irradiation. The Ag/AgBr/AgIn(MoO 4 ) 2 composites exhibit a strong absorbance in the visible region because of the surface plasmon resonance absorption of Ag nanocrystals. Compared with bare AgIn(MoO 4 ) 2 nanosheets, Ag/AgBr nanoparticles and Ag/AgIn(MoO 4 ) 2 composites, a dramatic enhancement in the degradation rate of tetracycline (TC) is observed over the Ag/AgBr/AgIn(MoO 4 ) 2 composites. The immense enhancement of the photocatalytic activity is attributed to the extended absorption in the visible-light region, effective charge separation, and synergistic enhancement induced by surface plasmon resonance (SPR) in the heterostructured Ag/AgBr/AgIn(MoO 4 ) 2 . This study provides new insight into the fabrication of highly efficient and stable ternary metal molybdate based plasmonic photocatalysts and facilitates their practical application to solve environmental issues. The mechanism for the photodegradation of TC over Ag/AgBr/AgIn(MoO 4 ) 2 is discussed in detail. [ABSTRACT FROM AUTHOR]

Magnetically separable, visible-light-driven Ni (1− x ) Cu ( x ) Fe 2 O 4 (Cu–Ni ferrite) photocatalysts have been successfully synthesized via a simple sol−gel precursor method. The prepared samples were characterized by a combination of various physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectrum (DRS) and photoluminescence (PL). Visible-light-driven photodegradation of tetracycline (TC) was carried out to evaluate the photocatalytic activity of the products. The copper doping can greatly enhance photocatalytic activity in comparison with pure NiFe 2 O 4 for degradation of TC. The significant enhancement of photoactivity can be ascribed to the reduction of the nickel ferrite band gap and lower recombination of photoinduced electron–hole pairs by Cu 2+ doping. In addition, the photocatalytic mechanism was analyzed by different active species trapping experiments. The results indicated that the h + and OH were the main active species for photocatalytic oxidation of TC in the aqueous solution. Moreover, the Cu–Ni ferrite photocatalysts exhibit excellent photostability and recyclability properties which are beneficial for its practical application. [ABSTRACT FROM AUTHOR]

Highlights: [•] MITP is obtained by surface imprinting technology and microwave heating method. [•] PMMA has been successfully formed and existed in the surface-imprinted layer. [•] PMMA improves the photocatalytic activity of traditional imprinted photocatalyst. [•] MITP can effectively select degradation of ENRH in binary antibiotic solution. [ABSTRACT FROM AUTHOR]

Abstract: In this letter, Ni2+ doped InVO4 nanocrystals were successfully synthesized by a simple one-pot microwave-assisted method. The energy bandgap of obtained samples can be precisely controlled by varying the Ni2+ doping amount. The O2 production rate of obtained Ni–InVO4 nanocrystals is higher than that of pure InVO4 nanocrystals under visible-light, which can be ascribed to the narrowed band gaps. The corresponding 1% doped sample N1 has the highest O2 production rate (394μmol/h) in all samples, which is 66% higher than the undoped sample N0. [Copyright &y& Elsevier]

Highlights: [•] A novel heterojunction CdS–WO3 photocatalyst is prepared via hydrothermal method. [•] The combination of 30%-CdS–70%-WO3 results in a highly active photocatalyst for the degradation of Ciprofloxacin. [•] Holes were the main active species of the CIP degradation. [•] The CdS–WO3 photocatalyst has good stability. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new composite surface molecular imprinting photocatalyst was synthesized. [•] The MIP photocatalyst played the highest photocatalytic activity. [•] The effects of various factors on the degradation behavior were investigated. [•] The first-kinetic and second-kinetic of photocatalytic degradation were studied. [ABSTRACT FROM AUTHOR]

Highlights: [•] InVO4 nanocrystals were prepared by the microwave-assisted method. [•] As-prepared products are 20nm-sized with high crystallinity. [•] InVO4 nanocrystals have greater activity than microspheres. [•] The visible-light response of InVO4 nanocrystals is weaker than microspheres. [•] The model of size-dependent activities is proposed based on our results. [Copyright &y& Elsevier]

Inthis paper, CdSe quantum dots (QDs) photocatalysts were successfullysynthesized by a hydrothermal method. The factors affecting synthesizedCdSe QDs were investigated under different experimental conditions.CdSe QDs were characterized by X-ray diffraction (XRD), Fourier transforminfrared (FT-IR) spectroscopy, transmission electron microscopy (TEM),ultraviolet–visible diffuse reflectance spectrophotometry (UV–visDRS), photoluminescence (PL) spectroscopy, and X-ray photoelectronspectroscopy (XPS). The photocatalytic activities of CdSe QDs wereevaluated on the decomposition of cefalexin under UV irradiation.The results showed that the degradation ratio of Cefalexin could reach70.34%. Based on the results, the possible mechanism of the photocatalyticreaction on cefalexin with CdSe QDs was discussed. [ABSTRACT FROM AUTHOR]

Visible-driven photocatalysis plays a critical role in solar energy conversion, but the efficiency is limited by the poor charge separation and utilization. Here, a ternary photocatalyst is constructed using Cu-In-Zn-S quantum dots (CIZS QDs), MoS 2 and carbon dots (CDs). Interestingly, transient photovoltage measurements confirm that MoS 2 has no assistance on the charge extraction rate, whereas CDs dramatically increases the attenuation constant of the charge recombination process (from 0.178 to 0.260 ms) due to its electron sinking effect. The optimal hydrogen production rate of CIZS/MoS 2 /CDs reaches 3706 μmol g-1 h-1, which is 6.65 and 148.24 times to that of CIZS QDs and MoS 2 , respectively. Further electrocatalytic tests indicate that MoS 2 is the main place for hydrogen evolution reaction, whereas CIZS and CDs are responsible for light harvesting and charge sinking, respectively. This work provides a useful guideline for the synergy of charge extraction and utilization process in composite photocatalyst design. Carbon dots are used for mediating highly efficient charge sinking, resulting in the increase of attenuation constant of surface charge carriers from 0.178 to 0.260 ms and 6.65 times enhancement of hydrogen evolution rate in CIZS/MoS 2 /CDs. [Display omitted] • Carbon-dots-mediated highly efficient charge sinking in CIZS/MoS 2 /CDs photocatalyst for hydrogen evolution. • The hydrogen production rate over the CIZS/MoS 2 /CDs has 6.65-fold increase over primal CIZS. • The attenuation constant of the surface charge carriers in CIZS/MoS 2 /CDs increases from 0.178 to 0.260 ms. [ABSTRACT FROM AUTHOR]

By skillfully introducing a conjugate electron donating ring into the g-C 3 N 4 framework, the as-prepared 3 wt% PPD/CN sample not only narrows the bandgap of g-C 3 N 4 , but also absorbs more solar light up to 600 nm. As a result, the optimal sample exhibited hydrogen escape under orange light (600 nm) and bare g-C 3 N 4 had almost no such performance. [Display omitted] • Benzene ring doping in the specific site of the network of g-C 3 N 4 was obtained. • It still has photoactivity that g-C 3 N 4 barely has under the orange light. • The 3 wt% PPD/CN can effectively cover more sufficient photo flux (λ = 600 nm). • The benzene ring incorporation of g-C 3 N 4 enhanced photogenerated carrier separating. Grafting π-conjugated donor units into graphitic carbon nitride (g-C 3 N 4) represents a promising alterative to improve its light absorption range and charge transfer kinetics. To this end, we here report an efficient intramolecular g-C 3 N 4 -based conjugated copolymers via the one-spot thermal copolymerization for not only reduces the bandgap to 2.56 eV and thus expand the visible-light harvesting capability, but also accelerates the separation ability of photogenerated excitons. Consequently, the copolymer of 3 wt% p-phenylenediamine with melamine exhibits extraordinary hydrogen (H 2) evolution rate of 1040 μmol g−1 h−1 under visible light. Interestingly, it still shows hydrogen production (5.29 μmol g−1 h−1) at λ = 600 nm (orange light). Systematic characterizations have proved that the optimal sample has high photocatalytic activity, due to rapid charge transfer kinetics and exciton separation. Our work sheds light on a molecular design to regulate charge-transfer dynamics among of polymeric semiconductors towards efficient solar-to-H 2 production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Z-scheme mechanism was demonstrated by ESR characterizations. • The high photocatalytic activity is owing to the successful fabrication of Z-scheme heterojunction and efficient charge separation. • Direct Z-scheme system enhances the separation of photogenerated charge carriers. • 0D/2D Zn-AgIn 5 S 8 QDs/α-Fe 2 O 3 heterostructures exhibit the efficient photocatalytic H 2 generation. Multinary sulfide quantum dots (QDs) have exhibited outstanding advantages including large surface areas, unique optical properties and adjustable band gap, which are beneficial for visible-active photocatalysis. However, the use of QDs also brings about serious issues of charge recombination and particle agglomeration. Here, a rational design of direct 0D/2D Z-scheme heterojunction of Zn-AgIn 5 S 8 /α-Fe 2 O 3 is described. Appropriate band alignment is conducive to the construction of Z-scheme heterostructures, thus enhancing the redox ability of the semiconductors and inhibiting the charge recombination. Simultaneously, the zeta potential differences between the two semiconductors can make them achieve a close interface contact by electrostatic adsorption and then the 0D Zn-AgIn 5 S 8 (ZAIS) QDs can be dispersed uniformly on 2D α-Fe 2 O 3 nanosheets, which can reduce the agglomeration of QDs. At the same time, the advantages of large specific surface area and short electron transmission path of QDs can also be exerted. Meanwhile, α-Fe 2 O 3 nanosheets with high conductivity can rapidly lead out the photogenerated charge carriers and thus suppress the recombination of the electrons and holes in QDs. The optimum nanocomposites with 3 wt% α-Fe 2 O 3 nanosheets display a photocatalytic H 2 evolution rate of 1.7 mmol g−1 h−1, 3.5 times to that of pure QDs, with an apparent quantum efficiency of 7.48% at 450 nm. Electrochemiluminescence spectra, time-resolved photoluminescence spectra and electron spin resonance spectra further testify the enhanced charge transfer and the direct Z-scheme mechanism of the 0D/2D heterojunction. This work emphasizes the suitable band matching to adjust the exciton properties and charge transfer characteristics of QDs by constructing Z-scheme heterojunction for efficient utilization of visible light. [ABSTRACT FROM AUTHOR]

With the development of visible-light-driven photocatalytic systems, the Z-scheme system has been paid more attention for water-splitting and contaminants degradation in an effort to the full utilization of superior band potential between two different semiconductors. Here we present systemic investigation of the reduced graphene oxide (RGO)-based composites, including RGO-Cu 2 O, RGO-Bi 2 WO 6 , RGO-Cu 2 O/Bi 2 WO 6 , Cu 2 O/Bi 2 WO 6 heterojunction and physical mixed RGO + Cu 2 O + Bi 2 WO 6 , to give a clear demonstration of the Z-scheme photocatalytic mechanism. The three-component RGO-Cu 2 O/Bi 2 WO 6 composite showed the highest photocatalytic activity on water splitting, which is about 3 times and 4 times that of RGO-Cu 2 O and Cu 2 O respectively. And it also exhibited an excellent photocatalytic performance with a 86% degradation rate for tetracycline that is about 3 (6) times as high as that of pure Cu 2 O (Bi 2 WO 6). These results demonstrate that the construction of RGO-Cu 2 O/Bi 2 WO 6 Z-scheme system is beneficial to water splitting and pollutant degradation for which the superior band potential of Cu 2 O and Bi 2 WO 6 are fully utilized. This work not only reports a new Z-scheme system of RGO-Cu 2 O/Bi 2 WO 6 but also provides a guide to the design of RGO-based photocatalysts. [ABSTRACT FROM AUTHOR]