Ni-doped ZnS nanomaterials were decorated on the surfaces of porous Ni foam as immobilized photocatalysts for H2 production by a solvothermal process. Effects of the Ni dopant content on the ...photocatalytic hydrogen production activity, morphology, optical property, crystalline properties, surface wetting, and photocurrent were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), photoluminescence (PL), photocurrent response, and contact angle meter. The surface changed from hydrophobic to superhydrophilic by decorating Ni-doped ZnS on the NiO/Ni foam substrate. A mechanism is proposed to elucidate the band positions of ZnS and NiO, together with the transfer of photoinduced electrons among ZnS, NiO, and Ni foam. The Ni-doped ZnS/NiO/Ni foam photocatalyst NZ5 showed much higher photocatalytic activity because of the matched band structure and the high conductivity of Ni foam. Meanwhile, the porous texture and superhydrophilic nature of the photocatalyst favor the light trapping, effective mass transfer of reactant molecules, and provide large contact area. Ni doping leads to a decreased band gap. The highest photocatalytic H2 generation activity reached 2500 μmol/g−1 h−1. After being operated for 3 cycles, the activity of the third run was 85% of that obtained at the first run.
•Activity of Ni-doped ZnS/NiO/Ni foam photocatalysts reaches 2500 μmol/g−1 h−1.•High activity results from matched band structure, porous texture and conductive Ni foam.•The porous texture favors transfer of reactant molecules and provides large contact area.•The hydrophobic surface became superhydrophilic by decorating Ni-doped ZnS.•A mechanism is proposed to elucidate band positions and electron transfer.
Stainless steel wire mesh/bismuth oxybromide (BiOBr) were synthesized as immobilized photocatalysts. The effects of conductive wire mesh substrate and calcination on the photocatalytic performance ...were investigated. The morphology, crystal structure, composition, and optical properties of hierarchical wire mesh/BiOBr photocatalyst were investigated. The degradation of 99% dye can be achieved within 50 min by S250 photocatalyst which was calcined at 250 °C. The recycled photocatalyst also shows good stability. The activity of the immobilized photocatalysts was enhanced by increasing the surface area (flower-like texture of BiOBr), facilitating separation of photogenerated charge carriers (good contact between BiOBr and conductive stainless steel wire mesh), and improving the crystal properties (facet effect, dominant (001) facets by calcination). This study provides a way to optimizing the activity of immobilized photocatalysts for the treatment of hazardous pollutants in wastewater.
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•BiOBr/stainless steel interface helps the separation of photogenerated carriers.•Calcined photocatalysts with dominant (001) facet have high activity (facet effect).•Flower-like BiOBr and wire-mesh substrate lead to the high surface area of the photocatalyst.•Lots of transport paths for dye molecules, large contact area, and BiOBr-stainless steel interface lead to high activity.•Degradation of 99% dye can be achieved within 50 min by S250 photocatalyst.
We combined reflection difference microscopy, electron transport measurements, and atomic force microscopy to characterize the mechanical and electrical anisotropy of few-layer black phosphorus. We ...were able to identify the lattice orientations of the two-dimensional material and construct suspended structures aligned with specific crystal axes. The approach allowed us to probe the anisotropic mechanical and electrical properties along each lattice axis in separate measurements. We measured the Young’s modulus of few-layer black phosphorus to be 58.6 ± 11.7 and 27.2 ± 4.1 GPa in zigzag and armchair directions. The breaking stress scaled almost linearly with the Young’s modulus and was measured to be 4.79 ± 1.43 and 2.31 ± 0.71 GPa in the two directions. We have also observed highly anisotropic transport behavior in black phosphorus and derived the conductance anisotropy to be 63.7%. The test results agreed well with theoretical predictions. Our work provided very valuable experimental data and suggested an effective characterization means for future studies on black phosphorus and anisotropic two-dimensional nanomaterials in general.
The major problems for photocatalysts are the poor visible light-driven activity, separation process for the recycling of photocatalysts, and fast recombination of photoexcited carriers. We tried to ...solve these problems by the growth of Bi2WO6 flower nanostructures on the conductive wire mesh substrates, and the deposition of Ag nanoparticles on Bi2WO6 using a double-potentiostatic electrodeposition method to make the visible-light driven metal wire mesh/Ag-Bi2WO6 as an immobilized photocatalyst. Close contact among Bi2WO6 with Ag nanoparticle and metal wire mesh facilitated effective separation of photoexcited charges, leading to improved photocatalytic activities. The results of diffuse reflection spectra, electrochemical impedance spectra, and photocurrent response confirmed the enhanced charge separation and increased optical absorption by the decoration of Ag nanoparticles. The optimized wire mesh/Ag-Bi2WO6 photocatalyst exhibited a high visible-light driven activity. Rhodamine B was completely degraded within 60 min of irradiation. Three-dimensional flower-like Bi2WO6 nanostructure and wire-mesh structure of the substrate maximize the contact area between photocatalyst and the dye molecules. Decorated Ag nanoparticle extended the range of absorption wavelength from UV light to visible light region. The immobilized photocatalyst can be easily recycled and reused without centrifugation and filtration process.
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•‧3D metal wire mesh/Ag-Bi2WO6 was prepared as an immobilized photocatalyst.•‧Wire mesh/Ag-flower-like Bi2WO6 shows enhanced photocatalytic activity.•‧Introducing Ag nanoparticle and metal wire mesh facilitated separation of photoexcited charges.•‧The major active species generated in the photocatalyst are .•O2− and h+.•‧Immobilized photocatalysts can be easily reused without centrifugation or filtration.
•Flower-like Bi2O3/Bi2WO6 was prepared by ionic liquid-solvothermal method and calcination.•Effects of ionic liquids and calcination on morphology and activity of photocatalysts were ...studied.•Incorporating ionic liquid leads to larger microflowers with more petal sheets.•The H2 production activity of Bi2O3/Bi2WO6 photocatalyst was studied for the first time.•The improved activity was due to p-n junction, increased surface area, and light absorption.
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A flower-like Bi2WO6-Bi2O3 photocatalyst was prepared by a two-step process, including an ionic liquid-assisted solvothermal step and calcination. The effects of the ionic liquids and calcination on the morphology, property, and photocatalytic performance of Bi2WO6-based photocatalysts were studied. The addition of ionic liquids during the preparation of Bi2WO6 based-materials lead to increased sizes of photocatalysts and the formation of more petal sheets in the flower-like microspheres. The results of XRD, XPS, and TEM confirm that Bi2WO6-Bi2O3 photocatalysts formed after the calcination treatment of Bi2WO6 photocatalyst in an air atmosphere. The Bi2WO6-Bi2O3 flower-like photocatalyst exhibits better photocatalytic H2 production activity than the Bi2WO6 photocatalyst. The improved activity of the Bi2WO6-Bi2O3 photocatalysts was attributed to their enhanced light absorption, increased surface area, matched band structure, and the inhibited recombination of the photogenerated charge carriers.
Rechargeable batteries are key in the field of electrochemical energy storage, and the development of advanced electrode materials is essential to meet the increasing demand of electrochemical energy ...storage devices with higher density of energy and power. Anode materials are the key components of batteries. However, the anode materials still suffer from several challenges such as low rate capability and poor cycling stability, limiting the development of high‐energy and high‐power batteries. In recent years, heterojunctions have received increasing attention from researchers as an emerging material, because the constructed heterostructures can significantly improve the rate capability and cycling stability of the materials. Although many research progress has been made in this field, it still lacks review articles that summarize this field in detail. Herein, this review presents the recent research progress of heterojunction‐type anode materials, focusing on the application of various types of heterojunctions in lithium/sodium‐ion batteries. Finally, the heterojunctions introduced in this review are summarized, and their future development is anticipated.
This review summarizes and unveils a comprehensive understanding of the electrochemical behavior and modification strategies of heterojunction‐type anode materials. Recent advances in heterojunction‐type anode materials are presented in terms of in‐depth understanding, characterization methods, and types of heterostructure. In particular, this review summarizes the current challenges in building the heterostructure and looks forward to the construction of the heterostructure.
Carbon dot-based nanomaterials show great potential for environmental pollution control and remediation applications. Herein, carbon dots/silica nanoaggregates for dye adsorption were easily ...synthesized
via
a hydrothermal reaction of N-doped carbon dots with (3-aminopropyl)triethoxysilane. The composition and structure of the resulting nanoaggregates were characterized using TEM, SEM, FT-IR and XPS. The adsorbent exhibited ultrahigh adsorption capability for alizarin red S (1327 mg g
−1
) and malachite green (4091 mg g
−1
), outperforming most of the reported adsorbents. The effects of pH, adsorbent dosage, contact time and initial dye concentration on adsorption capacities have been investigated. The adsorption isotherms and kinetics were well fitted using the Langmuir and pseudo-second order models, indicating that monolayer adsorption and chemisorption of dye molecules occurred on the surface of carbon dots/silica nanoaggregates. The fabrication of carbon dots/silica nanoaggregates is simple, low-cost and eco-friendly, and it is easy to separate the material from water for recycling in practical applications. To the best of our knowledge, this is the first investigation into the application of carbon dots/silica nanoaggregates for the adsorption of organic dyes, which facilitates the development of carbon dot-based nanomaterials for environmental applications.
A carbon dots/silica nanoaggregate adsorbent exhibits ultrahigh adsorption capability for Alizarin Red S (1327 mg g
−1
) and malachite green (4091 mg g
−1
).
It is crucial to remove heavy metals and dyes before discharging industrial effluents. Gauze substrate was surface-modified by coating with a polymeric adsorbent and a spray coating of BiOBr ...photocatalyst to develop a novel dual-functional membrane, polymer/BiOBr-modified gauze, for water remediation. The polymeric adsorbent was crosslinked to prevent the dissolving of the adsorbent during operation in contaminated water. The morphology and surface chemistry of the modified gauze were characterized before and after the adsorption of Ni2+. The surface wettability, isotherms, and kinetics of Ni2+ adsorption were studied. We also studied the effect of pH, initial Ni2+ concentration, monomer molar ratio, and monomer chemical structure on the Ni2+ adsorption capacity. To achieve a high Ni2+ adsorption capacity and good photocatalytic decolorization activity, the amount of decorated BiOBr was tuned by changing the spray-coating time to optimize the exposed BiOBr and polymer on the surface. The optimized dual-functional membrane PB20 possesses excellent adsorption capacity (650 mg g−1) for Ni2+ ions and photocatalytic decolorization activity (100% degradation of RhB within 7 min). Decorating the optimized amount of BiOBr on the surface can introduce photocatalytic decolorization activity without sacrificing the adsorption capacity for Ni2+.
SnSe/SnSe2 heterostructure composites with polypyrrole (PPy) coating layer and selenium (Se) vacancies are prepared by solvothermal and subsequent liquid-phase surface coating methods, and first ...reported as anode for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Results indicate that PPy coating can effectively stabilize the structure and improve the electronic conductivity of the material, the heterostructure formed by SnSe and SnSe2 can reduce the reaction barrier and promote charge transfer, and the Se vacancies can provide more active sites for electron transfer and relieve structural strain. In addition, adjusting the molar ratio of SnSe and SnSe2 proves that the as-prepared Sn3Se5@PPy composite has the best rate and excellent cycle performance. Attributed to the difference in alloying between lithium-ion storage and sodium-ion storage, the Sn3Se5@PPy composite deliverers a higher specific capacity as anode for LIBs. It has a higher capacity retention and better rate performance for SIBs. The engineering design of cation doping-induced defects provides a new method for the structural design of high-performance anode materials.
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•SnSe–SnSe2 after Sn2+ doping into Sn4+ can lead to the formation of Se vacancies.•The Se vacancies can provide more active sites for electron transfer.•The heterostructure can promote the charge transfer and reduce the reaction barrier.
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•The SAS process resulted in DMY particles with a mean particle size of 169.1 nm.•DMY flow rate and temperature showed significant influence on the particle size.•Reduced particle ...size of DMY enhanced diverse biological efficacies.
Owing to its poor solubility, the applicability of dihydromyricetin (DMY) is limited in various biomedical applications. To overcome this issue, nano-sized DMY particles (DMY NPs) were fabricated using the supercritical antisolvent (SAS) approach for improving the bioavailability of DMY. Initially, the experimental conditions were optimized such as temperature of 45 °C, pressure of 8 MPa, and DMY solution flow rate of 0.5 mL/min, resulting in the DMY particles at a mean particle size of 169.1 ± 23.7 nm. Further, the physicochemical characteristics of the resultant DMY NPs were evaluated using various characterization techniques. The DMY NPs with reduced particle size and improved dissolution rate resulted in improved anticancer, antibacterial, and biofilm inhibition efficacies, comparable to that of unprocessed DMY. Together, the designed DMY NPs using the SAS process have great potential in food and pharmaceutical industries.
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