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1.
Novel ZnIn2S4/CaTiO3 nanocubes were prepared by a two-step method and used as a visible light photocatalyst for efficient hydrogen production. The control of the content of CaTiO3 could effectively change the photocatalytic H2 production activity of ZnIn2S4/CaTiO3 nanocubes, and the maximum H2 evolution amount reached to 133116.43 μmol g−1 in 6 h. The photocatalytic hydrogen production efficiency of ZnIn2S4/CaTiO3 nanocubes was almost 4.5 times higher than that of pure ZnIn2S4. The electrochemical impedance spectrum of ZnIn2S4/CaTiO3 exhibited the smallest arc radius, time-resolved PL spectrum showed that the carrier lifetime of ZnIn2S4/CaTiO3 nanocubes was 3.29 ns, and the photocurrent density of ZnIn2S4/CaTiO3 reached to 0.81 μA cm−2. The prepared ZnIn2S4/CaTiO3 nanocubes increased visible light absorption, improved the separation and transfer of photo-generated electrons and holes, and inhibited the recombination of photo-generated electron-hole pairs. ZnIn2S4/CaTiO3 nanocubes exhibited the enhanced photocatalytic activity and high stability, and could be used as promising photocatalyst for hydrogen production application.  相似文献   

2.
The ZnIn2S4/CdS hollow core-shell nanoheterostructure with bimetallic synergism is synthesized via a hybrid chemical method. As revealed, the ZnIn2S4/CdS hollow core-shell nanoheterostructure (ZnIn2S4/CdS-3) exhibits remarkable visible light photocatalytic hydrogen evolution (~5209.43 μmol·g?1·h?1, AQE of ~20.26%) than that of single CdS (~40 folds) and single ZnIn2S4 (~12 folds), and achieves decent photocatalytic stability (average HER performance of ~5056.80 μmol·g?1·h?1), which is mainly ascribed to that, the formed ZnIn2S4/CdS heterostructure with appropriate potential gradient and Zn/In bimetallic synergism can improve carrier transportation, including increasing carrier transportation, prolonging lifetime and decreasing recombination, the hollow core-shell nanostructure can provide abundant active sites and increase solar efficiency, while can maintain a photocatalytic stability.  相似文献   

3.
Developing low-cost, highly efficient and robust photocatalystic hydrogen evolution system is a promising solution to environmental and energy crisis. Herein, a Z-scheme Cu3P/ZnIn2S4 heterojunction photocatalyst was successfully constructed for the first time via a facile solution-phase hybridization method. The optimized Cu3P/ZIS composite exhibited the highest H2 production rate of 2561.1 μmol g−1 h−1 under visible light irradiation (>420 nm), which was 5.2 times greater than that of bare ZnIn2S4 and even exceeded the photocatalytic performance of Pt/ZIS composite. The apparent quantum yield of 10 wt% Cu3P/ZnIn2S4 can reach 22.3% at 420 nm. The huge boost of photocatalytic hydrogen evolution activity is ascribed to the formation of heterojunction with the built in electric field within Cu3P/ZnIn2S4 and Z-scheme charge carriers transfer pathway, which result in efficient separation and migration of charge carriers. In addition, both experimental and theoretical calculation confirmed that the charge-carriers transfer pathway of Cu3P/ZnIn2S4 photocatalyst follows the Z-scheme mechanism instead of conventional type-Ⅱ heterojunction mechanism. This work is considered helpful for getting a great deal of insight into constructing high-activity and cost-effective transition metal phosphides (TMPs) based photcatalytic hydrogen production system and rationally designing Z-scheme heterojunction photocatalyst.  相似文献   

4.
The MoS2/ZnIn2S4 composites with MoS2 anchored on the surface of ZnIn2S4 microspheres were fabricated by a facile solvothermal method. To clarify the crystal phases, morphologies, chemical compositions, optical properties, and special surface areas of the obtained photocatalysts, the corresponding characterization measurements were performed. The photocatalytic H2 evolution activities of MoS2/ZnIn2S4 composites were evaluated and compared with using lactic acid as sacrificial reagents. The results showed that integrating MoS2 with ZnIn2S4 could remarkably boost the photocatalytic H2 evolution performance and the maximum H2 evolution rate of 201 μmol h?1 was achieved over 1 wt% MoS2 loading on the ZnIn2S4, corresponding to the apparent quantum efficiency (AQE) about 3.08% at 420 nm monochromatic light. The photoelectrochemical tests and photoluminescence spectra (PL) versified that the efficient charge transfer and separation were achieved over MoS2/ZnIn2S4 composite in contrast with single ZnIn2S4, which would significantly benefit the enhancement of photocatalytic H2 activity. This work provides a desired strategy to design and synthesize the visible-light-response photocatalysts with MoS2 as cocatalysts to enhance the photocatalytic activity.  相似文献   

5.
An intervening barrier for photocatalytic water decomposition and pollutant degradation is the frustratingly quick recombination of e - h+ pairs. Delicate design of heterojunction photocatalysts by coupling the semiconductors at nanoscale with well-matched geometrical and electronic alignments is an effective strategy to ameliorate the charge separation. Here a facile and environment-friendly l-cysteine-assisted hydrothermal process under weakly alkaline conditions is demonstrated for the first time to fabricate ZnIn2S4/In(OH)3 hollow microspheres with intimate contact, which are verified by XRD, SEM, (HR)TEM, XPS, N2 adsorption-desorption, UV–Vis DRS and photoluminescence spectra. ZnIn2S4/In(OH)3 heterostructure (L-cys/Zn2+ = 4, molar ratio) with a band-gap of 2.50 eV, demonstrates the best photocatalytic performance for water reduction and MB degradation under visible light, outperforming its counterparts (In(OH)3 and ZnIn2S4). The excellent activity of ZnIn2S4/In(OH)3 heterostructure arises from the intercrossed band-edge positions as well as the unique hollow structure with large surface area and wide pore-size distribution, which are beneficial for the efficient charge migration from bulk to surface as well as at the interface between ZnIn2S4 and In(OH)3. This work provides an efficient and eco-friendly strategy for one-pot synthesis of heterostructured composites with intimate contact for photocatalytic application.  相似文献   

6.
Efficient separation of electrons and holes, associated with the reduction and oxidation, is of great importance in a photocatalytic reaction. 3D hierarchical core-shell-like ZnIn2S4@In(OH)3 microspheres have been fabricated by a facile hydrothermal method via controlling the sulfur source. The marigold-like spherical ZnIn2S4 induced the in situ growth of cubic In(OH)3 nanosheets as the outer shell, which efficiently transferred the photogenerated electrons and achieved efficient charge separation efficiency for highly photocatalytic H2 production. Moreover, the intimate interfacial contact between ZnIn2S4 core and In(OH)3 shell offered rectified charge transfer directions, which further boosted the charge separation. In consequence, the photocatalytic H2 evolution under visible light irradiation was achieved on wide-gap In(OH)3 owing to ZnIn2S4 as a cocatalyst, and a prominent photocatalytic H2 production of 2088 μmol g−1 was obtained on core-shell-like ZnIn2S4@In(OH)3 structure with an apparent quantum efficiency of 1.45% (400 nm), which was nearly 2-folds higher of H2 production rate than the pristine ZnIn2S4. This work provides a prototype material for high efficiency of hydrogen evolution, and gives a new insight for the development of efficient heterojunction photocatalysts.  相似文献   

7.
A series of rare earth (RE) ions (La3+, Ce3+, Gd3+, Er3+ or Y3+) modified ZnIn2S4 photocatalysts (RE-ZnIn2S4) were prepared using the hydrothermal method and characterized by various analysis techniques, such as UV–Vis diffusive reflectance spectroscopy, X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller surface analyzer, photoluminescence spectroscopy and X-ray photoelectron spectroscopy. The results indicated that the RE element exists as the oxide RE2O3 and their modification can reduce ZnIn2S4 crystallite size, inhibit ZnIn2S4 grain growth, promote ZnIn2S4 crystallite self-organization into a micro-sphere flower-like morphology, increase ZnIn2S4 surface area and total pore volume, and bring rich defects to ZnIn2S4. The photocatalytic activities of RE-ZnIn2S4 were evaluated based on photocatalytic hydrogen production from water under visible-light irradiation and the hydrogen production efficiency increased by 46%, 53%, 61%, 69%, and 106% after adding 2.0 wt% of Y, Gd, Er, Ce and La, respectively. The relationship between the photocatalytic activity of RE-ZnIn2S4 and the RE properties was discussed.  相似文献   

8.
We here report the fabrication of a core-shell WO3@ZnIn2S4 heterostructure by an interfacial seeding growth strategy, which is implemented by direct growth of ZnIn2S4 nanosheets on the surface of WO3 nanorods with forming a strong electronic interaction between two semiconductors that are beneficial for promoting the interfacial charge transfer. Systematic studies demonstrate that the WO3@ZnIn2S4 nanohybrids hold superior performance for photocatalytic hydrogen generation under visible light irradiation with a production rate of 3900 μmol g−1 h−1. This work provides an effective approach to construct the direct Z-scheme photocatalytic systems for efficient photocatalytic hydrogen evolution, which would be significant for the design of more direct Z-scheme system for various photocatalytic applications.  相似文献   

9.
In the photocatalytic water splitting hydrogen production system, the key to efficient use of solar energy is to choose a suitable photocatalyst. As an important ternary sulfide, ZnIn2S4 (ZIS) has attracted wide attention because of its narrow band gap (Eg = 2.3–2.8 eV) and wide light absorption range. However, further modification was still needed. Therefore, in this work, the unique C/ZIS hollow tubes with nano-flakes were prepared by a simple solvothermal method. To a large extent, this unique structure increased the utilization of light and active sites. Moreover, the dissolution of PAN during the solvothermal process caused the carbon element to be uniformly doped into the hollow tube framework. After a series of characterization results, C/ZIS-3.0 has the best hydrogen release rate (1241.94 μmol g−1 h−1) and good cyclability under visible light irradiation (λ ≥ 420 nm). And its unique morphology and possible catalytic mechanism were further discussed.  相似文献   

10.
Herein we report a heterostructure with ultrathin nanosheets of Co-doped molybdenum sulfide on CdS nanorod array (donated as CdS@CoMo2S4/MoS2) by hydrothermal synthesis. Firstly, elemental Co doping MoS2 (CoMo2S4) delivers the double benefits of increased active sites and enhanced conductivity. Secondly, the structural characteristics maximally exposes the MoS2 edges and enlarges interfacial contact area between the composite catalyst and electrolyte, as well as the efficient interfacial charge transfer. The ratio of CoMo2S4/MoS2 in CdS@CoMo2S4/MoS2 plays a crucial role for the enhanced photo-assistant electrocatalytic hydrogen evolution reaction (HER). We can tune the ratio of CoMo2S4/MoS2 by controlling the preparation time or the ratio of precursor of Co/Mo. The catalyst with predominant MoS2 phase shows superior photocatalytic HER performance with a high H2 production rate of 46.60 μmol mg−1 h−1. Meanwhile, the catalyst with predominant CoMo2S4 phase exhibits not only relatively low overpotential of 172 mV at 10 mA cm−2, which outperforms most values that have been reported on catalyst supported on ITO substrate, but also possesses H2 production rate of 23.47 μmol mg−1 h−1. The superior photo-assistant electrocatalytic HER activity results from the synergistically structural and electronic modulations, as well as the proper energy band alignment between MoS2 and CdS. This investigation could provide an approach to integrate the electro- and photocatalytic activities for HER, especially the photo responding behaviour at a bias potential which is meaningful to produce H2 for actual application.  相似文献   

11.
Focused on energy and environment issues, in present investigation, an economical and eco-friendly photocatalyst for hydrogen evolution in water splitting reaction has been designed and fabricated. The characteristics by XRD, TEM, XPS and AFM confirmed that an octahedral H2Ta2O6 is uniformly capsuled by ZnIn2S4 thin clothes to form a package ZnIn2S4/H2Ta2O6 heterojunction. The assembled ZnIn2S4/H2Ta2O6 exhibits superior hydrogen generated performance with a value of 3217.31 μmol g−1•h−1 under simulated sunlight irradiation, without obvious deactivation in five consecutive cycles. The enhanced activity and reusability are mainly attributed to ultrathin clothe-like shell, the well-matched band structure and a large tight contact interface in the package type construction, which can promote redox ability, extend light harvesting range and boost charge separation efficiency. The present study proposes a new design idea to assemble a highly efficient and durable photocatalyst for solar hydrogen generation by splitting water.  相似文献   

12.
Reasonable design and fabrication of core/shell heterojunction has deemed as an efficient strategy to boost the transport and separation of photoinduced charge pairs in semiconductor-based photocatalytic system. Herein, a novel dual-functional ZnIn2S4/Ta3N5 (ZIS/TN) nanocomposite with intimate contacts was fabricated with a one-pot eco-friendly hydrothermal method. This core/shell heterojunction consisting of ZnIn2S4 nanosheet shell and Ta3N5 nanoparticle core is observed to possess the enhanced visible light harvesting capacity, increased specific surface areas, more high-speed charge nanochannels and accelerated charge transfer and separation. Thus, as prepared ZIS/TN nanocomposite displayed dramatically strengthened dual-functional photocatalytic performances of hydrogen production and tetracycline hydrochloride (TCH) photodegradation. As a result, the improved H2-production activity of 834.86 μmol g−1 h−1 was obtained by sample ZIS/TN-2, which is 6.07 times higher than that of pure ZnIn2S4 nanosheet. Moreover, the highest TCH photodegradation efficiency of 89.95% is achieved by the sample ZIS/TN-3, which is 1.90 and 11.01 times more than those of bare ZnIn2S4 and Ta3N5. In addition, the core/shell heterojunction exhibits super photostability and reusability due to the protection of external ZnIn2S4 layer from the photocorrosion of Ta3N5 core. Furthermore, the possible reaction mechanisms and the degradation intermediate products of TCH were also put forwarded in depth based on transient photocurrent response, active species tapping experiment, electronspin response (ESR) technique and HPLC-MS method. This work could stimulate an innovative vision in constructing dual-functional Ta3N5-based core/shell heterostructure with wonderful photocatalytic H2 evolution and antibiotic pollutant photodegradation activities.  相似文献   

13.
A series of SnS2/ZnIn2S4 (x-SS/ZIS) photocatalysts with different mass ratios of SnS2 were prepared by a hydrothermal method. The resulted composites were used for photocatalytic hydrogen evolution under visible light excitation. All the SS/ZIS composites exhibited significantly enhanced photocatalytic activity for H2 evolution. Obviously, the highest H2 evolution rate of 769 μmol g?1 h?1 was observed over 2.5-SS/ZIS, which was approximately 10.5 times that of the ZnIn2S4 (73 μmol g?1 h?1). The enhanced photocatalytic performance was attributed to the successful construction of SnS2/ZnIn2S4 heterojunctions, leading to rapid charge separation and fast transfer of the photo-generated electrons and holes under light irradiation. On the basis of PL, electrochemical impedance spectroscopy (EIS), photocurrent measurements and the H2 evolution tests, a plausible photocatalytic mechanism was proposed.  相似文献   

14.
The MoS2/Ti3C2 catalyst with a unique sphere/sheet structure were prepared by hydrothermal method. The MoS2/Ti3C2 heterostructure loading 30% Ti3C2 has a maximum hydrogen production rate of 6144.7  μmol g−1 h−1, which are 2.3 times higher than those of the pure MoS2. The heterostructure maintains a high catalytic activity within 4 cycles. The heterostructure not only effectively reduce the recombination of photogenerated electrons and holes, but also provide more activation sites, which promotes the photocatalytic hydrogen evolution reaction (HER). These works can provide reference for the development of efficient catalysts in photocatalytic hydrogen evolution.  相似文献   

15.
The exploration of photocatalytic transformation of solar energy into H2 through water splitting is an important direction towards sustainable and non-polluting energy in order to cover energy necessity partially. Ternary transition metal chalcogenides have been attracted attention among the other chalcogenides due to their potential applications in the photocatalytic and electrocatalytic hydrogen evolution. Herein, Cu2WS4 nanocubes and Cu2WSe4 nanosheets have been synthesized through a facile hot-injection method to benefit from the advantages such as minimizing the required pressure and reaction time by this technique. The photocatalytic hydrogen evolution activities of Cu2WS4 and Cu2WSe4 have been investigated under the visible light irradiation by using eosin-Y (EY) dye and triethanolamine (TEOA) as a photosensitizer and an electron donor, respectively. Cu2WS4 nanocubes have exhibited higher photocatalytic activity and stability than Cu2WSe4 nanosheets. The photocatalytic HER rates of Cu2WS4 and Cu2WSe4 have been determined as 1260 μmol g−1 h−1 and 861 μmol g−1 h−1, respectively. Photocatalytic HER activities were figured out in the order of Cu2WS4 > Cu2WSe4 which could be attributed to differences between proton reduction potential and the conduction band energy levels.  相似文献   

16.
The hydrothermal preparation of NiCo2S4/ZnIn2S4 photocatalysts with different mass ratios is studied. Ni-cobalt bimetallic sulfide nanosheets are grown on zinc-indium bimetallic sulfide to form a compact heterojunction. First, both NiCo2S4 and ZnIn2S4 exhibit N-type semiconductor characteristics, a heterojunction formed by both can reduce the surface reaction energy barrier and use its synergy, strengthening the charge self-diffusion between the two semiconductors, it means the formation of a strong electric field. From the electron transfer path and band structure, NiCo2S4/ZnIn2S4 has S-scheme heterojunction characteristics. NiCo2S4 is a reducing photocatalyst (RP), and ZnIn2S4 is an oxidative photocatalyst (OP). Under the action of built-in electric field (BIEF), strong photogenic electrons and holes exist in CB of RP (NiCo2S4) and VB of OP (ZnIn2S4). Thus, the overall redox capacity of the NiCo2S4/ZnIn2S4 heterojunction is enhanced. Using visible light, the composite material can be used for photocatalytic hydrogen production. It is further shown that the composite material has a good effect in photocatalytic hydrogen production under the sensitizer eosin Y (EY) system. The optimal hydrogen production is about 221.75 μmol when the mass ratios of NiCo2S4/ZnIn2S4 is 20%, and the photocatalytic activity of the composite is about 47 times that of ZnIn2S4. Notably, the stability of the composites is the better. A reasonable photo-catalytic mechanism is proposed based on the band gap and photoelectrochemical properties of heterojunction.  相似文献   

17.
Hexagonal ZnIn2S4 photocatalysts with 3D-hierarchical persimmon-like shape have been successfully synthesized via an oleylamine (OA)-assisted solvothermal method. Hydrogen evolution experiments revealed that the obtained hierarchical ZnIn2S4 possessed good photocatalytic activity, e.g. hydrogen production rate reached to 220.45 μmol h−1 and the quantum yield was up to 13.16% when 3% Pt was loaded. Further delicate tuning the percentage of exposed facet of the obtained ZnIn2S4 crystals, it was found that the increase of {006} facets, terminated by metal ions, would improve their photocatalytic activity, and the relationship between the crystal structure and photocatalytic properties had been studied.  相似文献   

18.
Designing efficient photocatalytic systems for hydrogen evolution is extremely important from the viewpoint of the energy crisis. Highly crystalline heterostructure catalysts have been established, considering their interface electric field effect and structural features, which can help improve their photocatalytic hydrogen-production activity. In this study, we fabricated a highly crystalline heterojunction consisting of ZnFe2O4 nanobricks anchored onto 2D molybdenum disulfide (MoS2) nanosheets (i.e., ZnFe2O4/MoS2) via a hydrothermal approach. The optimized ZnFe2O4/MoS2 photocatalyst, with a ZnFe2O4 content of 7.5 wt%, exhibited a high hydrogen-production rate of 142.1 μmol h−1 g−1, which was 10.3 times greater than that for the pristine ZnFe2O4 under identical conditions. The photoelectrochemical results revealed that the ZnFe2O4/MoS2 heterojunction considerably diminished the recombination of electrons and holes and promoted efficient charge transfer. Subsequently, the plausible Z-scheme mechanism for photocatalytic hydrogen production under white-LED light irradiation was discussed. Additionally, the influence of cocatalysts on the photocatalytic hydrogen evolution for the ZnFe2O4/MoS2 heterostructure was investigated. This work has demonstrated a simplified coupling of one-dimensional or zero-dimensional structures with 2D nanosheets for improving the photocatalytic hydrogen production activity as well as confirmed that MoS2 is a viable substitute for precious metal-free photocatalysis.  相似文献   

19.
Graphite-like carbon nitride (g-C3N4) 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 Cu7.2S4 with outstanding NIR absorption was successfully introduced to g-C3N4 nanosheets through a simple in-situ growth procedure. As expected, the constructed Cu7.2S4/g-C3N4 (CSCN) photocatalysts exhibit superior H2 production activity of 82 μmol g−1 h−1 under NIR light irradiation (λ > 800 nm), which outperforms currently reported g–C3N4–based NIR-driven H2 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 Cu7.2S4/g-C3N4 photocatalytic system for the transformation of NIR solar energy into hydrogen.  相似文献   

20.
Challenge remains to develop a high activity of photocatalyst for large-scale industrial application in photocatalytic selective conversion of biomass alcohols into the value-added chemicals accompany with H2 evolution in aqueous solution. Herein, ReS2 as high efficiency co-catalyst is utilized to modify the flower-like ZnIn2S4 (ZIS) microspheres to obtain heterojunction composite, result in dramatically enhancements in photocatalytic oxidation of furfural alcohols cooperative with H2 evolution. Further studies show that the optimal catalyst containing 4.08 wt% ReS2 (RZIS-3) realize remarkably generation rates of H2 and furfural at 3092.9 and 2981.1 μmol g?1 h?1, respectively, nearly 12 times faster than that of blank ZnIn2S4. Mechanism studies verify that the migration of the photogenerated carriers from ZnIn2S4 to ReS2 leading to the remarkably photoactivity of the composite. Moreover, the typical photocatalysis not rely on a single model substrate, and high performance of the composite has been identified for the oxidation of other alcohols biomass intermediate to value-added aldehydes/ketones, providing a new insight for design and fabrication of the novel photocatalytic hydrogen evolution systems.  相似文献   

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