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Tailoring advanced anisotropy-driven efficient separation and migration of photogenerated carriers is a pivotal stride toward enhancing photocatalytic activity. Here, CdS-MoS2 binary photocatalysts are tailored into a dumbbell shape by leveraging the rod-shaped morphology of CdS and employing an in situ tip-induction strategy. To further enhance the photocatalytic activity, an in situ photo-deposition strategy is incorporated to cultivate MnOx particles on the dumbbell-shaped CdS-MoS2. The in situ deposition of MnOx effectively isolated the oxidatively active sites on the CdS surface, emphasizing the reductively active crystalline face of CdS, specifically the (002) face. Benefiting from its robust activity as a reduction active site, MoS2 adeptly captures photogenerated electrons, facilitating the reduction of H+ to produce hydrogen. The anisotropically driven separation of CdS photogenerated carriers markedly mitigates the Coulomb force or binding force of the photogenerated electrons, thus promoting a smoother migration toward the active site for photocatalytic hydrogen evolution. The hydrogen evolution rate of 35MnOx-CdS-MoS2-3 surpasses that of CdS by nearly an order of magnitude, achieving a quantum efficiency of 22.30% at 450 nm. Under simulated solar irradiation, it attains a rate of 42.86 mmol g-1 h-1. This work imparts valuable insights for the design of dual co-catalysts, anisotropy-driven spatial vectorial charge separation and migration, and the analysis of migration pathways of photogenerated carriers.
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Graphdiyne (GDY) is a new two-dimensional carbon network material composed of sp2 hybrid carbon and sp hybrid carbon conjugation. It has unique physical and chemical properties, such as high porosity, good electrical conductivity, high carrier mobility, adjustable band gap, and so on. The preparation of GDY and GDY derivatives by adjusting physical and chemical methods and changing monomers has become the key material in the fields of photocatalysis, energy storage, life science, and so on. In this paper, new methods for controllable growth of GDY are reviewed, including liquid phase chemical classical total synthesis, chemical vapor deposition, the interface method, the explosion method, and the mechanically driven ball milling method. FT-IR, Raman, NMR, and XAS are the main means to characterize the structure of GDY. Finally, the representative application of GDY in the field of photocatalytic hydrogen evolution is summarized, and its future development has been explored.
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The charge density and charge transfer resistance of the assisting catalyst have a significant impact on the hydrogen evolution performance of bimetallic sulfides. However, existing mechanistic discussions often overlook the charge density between the two catalysts and whether the assisting catalyst produces enough photo-generated electrons. Here, we propose a simple method for the synthesis of 2-acetylene-(copper metal-organic frameworks) (ACu-MOFs) to improve the hydrogen evolution performance of bimetallic sulfides. Compared to copper metal-organic frameworks (Cu-MOFs), these ACu-MOFs have higher charge density and lower charge transfer resistance. More importantly, the introduction of alkyne-based Cu-MOFs further promotes the hydrogen evolution performance of bimetallic sulfides under 5 W LED light, and XPS is used to determine the difference in charge density between ACu-MOFs and Cu-MOFs and the improvement in contact electron transfer after bimetallic sulfide modification. This work mainly discusses the charge density, charge transfer resistance, and the number of photo-excited electrons generated, and provides a reasonable explanation.
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In the case of CO2 thermal-catalytic hydrogenation, highly selective olefin generation and subsequent olefin secondary reactions to fuel hydrocarbons in an ultra-short residence time is a huge challenge, especially under industrially feasible conditions. Here, we report a pioneering synthetic process that achieves selective production of high-volume commercial gasoline with the assistance of fast response mechanism. In situ experiments and DFT calculations demonstrate that the designed NaFeGaZr presents exceptional carbiding prowess, and swiftly forms carbides even at extremely brief gas residence times, facilitating olefin production. The created successive hollow zeolite HZSM-5 further reinforces aromatization of olefin diffused from NaFeGaZr via optimized mass transfer in the hollow channel of zeolite. Benefiting from its rapid response mechanism within the multifunctional catalytic system, this catalyst effectively prevents the excessive hydrogenation of intermediates and controls the swift conversion of intermediates into aromatics, even in high-throughput settings. This enables a rapid one-step synthesis of high-quality gasoline-range hydrocarbons without any post-treatment, with high commercial product compatibility and space-time yield up to 0.9â kggasoline â kgcat -1 â h-1. These findings from the current work can provide a shed for the preparation of efficient catalysts and in-depth understanding of C1 catalysis in industrial level.
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As a new two-dimensional (2D) carbon hybrid material, graphdiyne has attracted much attention due to its good conductivity, adjustable electronic structure, and special electron transfer enhancement properties. In this work, graphdiyne/CuO and NiMoO4/GDY/CuO composite catalysts were prepared by cross coupling method and high temperature annealing method. The CuI introduced by clever design not only acts as a catalytic coupling but also as a precursor of CuO. The CuO produced by the postprocessing improves the inefficient charge separation of graphdiyne and provides a good acceptor for the consumption of unwanted holes. The good conductivity and strong reduction ability of graphdiyne play key roles in the performance improvement of the composite catalyst. Under the dual evidence of XPS and in situ XPS, the charge transfer mode of double S-scheme heterojunction with graphdiyne as the active site of hydrogen evolution is constructed reasonably, which not only gives full play to the performance advantages of graphdiyne but also effectively improves the separation efficiency of photogenerated carriers. In this study, a clean and efficient multicomponent system was constructed by graphdiyne, which opened up a broad application prospect in the field of photocatalytic hydrogen production.
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A new simulation model for light transmission of broad-spectrum artificial light in case 1 water is introduced in this paper. The model simulates spectrum changes of fishing lamps due to absorption and scattering of seawater. According to underwater spectrum changes, this model restores the light field generated by fishing lamps and demonstrates the distribution of visual stimuli to marine organisms. The accuracy of the transmission model is verified by comparing it with experimental data. In addition, by comparing the simulation results of light transmission models of different fishing lamps in seawater of various fishing grounds, we investigate why current light-emitting diode (LED) lights are not as effective as metal halide (MH) lamps for light fishing. Lastly, suggestions for future optimization of LED fishing lamps in terms of light distribution design and spectrum configuration are provided.
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Luz , Água , IluminaçãoRESUMO
Here, an S-scheme heterojunction was constructed on the basis of the modification of a Ni-based metal-organic framework (Ni-MOF) by different in situ treatment strategies. First, NiS2, NiO, and Ni2P were derived in situ on the surface of Ni-MOF through surface sulfonation, oxidation, and phosphatizing treatments. They can efficiently accept the electrons from the conduction band of Ni-MOF as the trap centers, thus improving the hydrogen production activity. Additionally, phosphatizing makes the electronegativity of Ni-MOF/P stronger than that of the original Ni-MOF, which can enhance the absorption of protons, thus promoting the hydrogen evolution reaction. Next, the S-scheme heterojunction was successfully built by the coupling of 2D CeO2 with Ni-MOF/P. The maximum hydrogen production rate of the hybrid catalyst (6.337 mmol g-1 h-1) is 14.18 times that of the untreated Ni-MOF due to the full utilization of photo-induced electrons. Finally, the probable hydrogen evolution mechanism was proposed by analyzing a series of characterization results and by the density functional theory (DFT) calculation.
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Graphdiyne (g-CnH2n-2) is a new carbon material composed of sp and sp2 hybrid carbon atoms. Since the synthesis by Li's team, graphdiyne has been widely studied in other fields because of its excellent properties. In this paper, graphdiyne was synthesized from copper-containing materials and the composite GDY/CuI/MIL-53(Al) S-scheme heterojunction is prepared for photocatalytic cracking of water to produce hydrogen. First, GDY/CuI was prepared by organic synthesis, and then GDY/CuI was anchored on the surface of MIL-53(Al) by in situ ultrasonic stirring. After the continuous optimization of experimental conditions, the final hydrogen evolution rate is much higher than that of MIL-53(Al). This efficient photocatalytic performance can be attributed to the S-scheme heterojunction formed by the unique energy band arrangement. At the same time, the mechanism of charge transfer was demonstrated by in situ irradiation X-ray photoelectron spectroscopy. The strong interaction among the three strongly promotes the separation and transfer of photogenerated electron-hole pairs.
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The construction of interfacial effects and chemical bonds between catalysts is one of the effective strategies to facilitate photogenerated electron transfer. A novel hollow cubic CoS is derived from Co-ZIF-9 and the S-C bond is successfully constructed between CoS and g-C3N4. The S-C bond acts as a bridge for electronic transmission, allowing the rapid transmission of photoelectron to hydrogen evolution active site in CoS. In addition, the results of electrochemical impedance spectroscopy and time-resolved photoluminescence spectroscopy show that the S-C bond acts as a bridge to quickly transfer photogenerated carriers in the composite material, and achieves the effect of high-efficiency hydrogen evolution. The hydrogen production of SgZ-45 reaches 9545 µmol·g-1 in 5 h, which is 53 and 12 times that of g-C3N4 and ZIF-9, respectively. The intrinsic mechanism of photoelectron transfer through S-C bonds can be further confirmed by density functional theory (DFT) calculations. This work provides new insights for building a chemical bond electron transfer bridge between MOF derivatives and nonmetallic photocatalytic materials.
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In view of the fact that the exposed catalytic active sites of single-metal MOFs cannot satisfy the efficient progress of the catalytic reaction, here we constructed a star-shaped bimetallic ZnCoMOF by introducing a Zn source by the partial ion exchange method and coprecipitation method. By controlling the quality of sodium hypophosphite, ZnCoMOF was subjected to different degrees of phosphating to optimize the experimental conditions. The introduction of the more electronegative P can attract more H+ to participate in the reduction reaction. The ZnCoMOF@CoP-5 S-scheme heterojunction was constructed in situ by generating CoP on the surface of ZnCoMOF under a PH3 reducing atmosphere, which exhibited excellent H2 evolution performance. This unique heterojunction effectively promotes the separation and transfer of e--h+ pairs, ensuring a strong redox capability. The best hydrogen-evolution performance of ZnCoMOF@CoP-5 under the EY sensitization system reaches 16â¯958 µmol h-1 g-1, which has significant advantages over the same type of materials and similar photocatalytic hydrogen-evolution work. Finally, the photocatalytic mechanism was demonstrated by an in situ XPS technique. Our work provides important ideas for the research of bimetallic MOFs in the field of photocatalytic hydrogen evolution.
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The development of clean energy is one of the effective strategies to solve carbon peak and carbon neutrality. The severe recombination of photogenerated carriers is one of the fundamental reasons that hinder the development of photocatalysis. In this work, NiCo-MOF/ZIF was obtained by the "ZIF on MOF" strategy for the first time, and a stable bonding state of surface P(δ-)-Co/Ni(δ+)-O(δ-) was formed on the surface of the catalyst by a one-step oxidation-phosphorus doping strategy. The X-ray photoelectron spectroscopy technique proves that phosphorus doping forms a unique bonding state on the surface of CoO-NiO. The novel surface bonding state can effectively inhibit the recombination of photogenerated carriers and can increase the migration rate of photogenerated electrons, which accelerates the process of photocatalytic hydrogen evolution. Photocatalytic hydrogen evolution kinetics verifies that the formation of P(δ-)-Co/Ni(δ+)-O(δ-) bonding states can accelerate the process of photocatalytic hydrogen evolution, and the durability of the catalyst is verified by cycling experiments. This work provides a new strategy for catalyst synthesis, new horizons, and effective strategies for the surface design of catalysts and the development of photocatalytic hydrogen evolution.
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Graphdiyne (g-Cn H2n-2 ), a novel two-dimension carbon allotrope material composed of a sp- and sp2 -hybrid carbon network, has been widely explored since it was synthesized for the first time by Li's group in 2010. A series distinct and excellent properties bestow graphdiyne excellent performance in many fields. Here, an innovative progress for preparing graphdiyne by using Cu+ contained material as catalyst is reported and the composite CuI-GD is coupled with flower-like NiAl-LDH to produce H2 from photocatalytic water splitting. The results of FTIR and Raman spectroscopy together reveal that graphdiyne nanosheets are synthesized successfully by employing a cross-coupling method. Photocatalytic hydrogen evolution performance shows that the hydrogen production activity of CuI-GD/NiAl-LDH has a 15- and 216-fold enhancement compared with CuI-GD and NiAl-LDH, respectively. A series of characterizations are carried out to expound the underlying reasons in the enhancement of the photocatalytic hydrogen production performance of CuI-GD/NiAl-LDH. Meanwhile, a possible mechanism for the photocatalytic hydrogen evolution process was proposed to understand the interaction among these materials.
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At present, inefficient charge separation of single photocatalyst impedes the development of photocatalytic hydrogen evolution. In this work, the CoSX /NiCo-LDH core-shell co-catalyst was cleverly designed, which exhibit high activity and high stability of hydrogen evolution in anhydrous ethanol system when coupled with CdS. Under visible light (λ≥420â nm) irradiation, the 3 %Co/NiCo/CdS composite photocatalyst exhibits a surprisingly high photocatalytic hydrogen evolution rate of 20.67â mmol g-1 h-1 , which is 59â times than that of the original CdS. Continuous light for 20â h still showed good cycle stability. In addition, the 3 %Co/NiCo/CdS composite catalyst also shows good hydrogen evolution performance under the Na2 S/Na2 SO3 and lactic acid system. The fluorescence (PL), ultraviolet-visible diffuse reflectance (UV-vis) and photoelectrochemical tests show that the coupling of CdS and CoSX /NiCo-LDH not only accelerates the effective transfer of charges, but also greatly increases the absorption range of CdS to visible light. Therefore, the hydrogen evolution activity of the composite photocatalyst has been significantly improved. This work will provide new insights for the construction of new co-catalysts and the development of composite catalysts for hydrogen evolution in multiple systems.
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Graphdiyne (GD), a new type of carbon allotrope formed by sp and sp2 hybrid carbon atoms, has attracted wide attention due to its high π-conjugation degree, special band structure, and uniformly distributed pores. In traditional synthesis methods, hexaethylbenzene was coupled on the substrate catalytic material (copper foil or foamed copper) to generate graphdiyne. In this work, CuI was used as the substrate catalytic material, and the CuI-GD composite was synthesized by cross-coupling in the pyridine solution of hexaethylbenzene. For the first time, Co3(PO4)2 was modified by the CuI-GD composite material to prepare a Co3(PO4)2/CuI-GD S-scheme heterojunction catalyst, which avoided the complicated process of removing the substrate catalytic material. Under the action of the internal electric field, electrons are induced to move quickly and directionally, and the powerful photogenerated electrons in the conduction band (CB) of GD and the holes in the valence band (VB) of CuI are retained to participate in the photocatalytic reaction. These advantages were combined with the high-energy acetylene bond in GD, which accelerated the catalytic reaction of the Co3(PO4)2/CuI-GD heterostructure. Electrochemical and fluorescence analysis showed that Co3(PO4)2/CuI-GD has faster electron and hole separation efficiency, lower hydrogen evolution overpotential, and higher carrier utilization. Therefore, Co3(PO4)2/CuI-GD exhibited good hydrogen evolution activity. This work shows that GD has broad prospects in designing high-performance photocatalyst systems.
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Improving the utilization rate of photogenerated electrons generated by visible light excitation is an important factor to improve the activity of photocatalytic decomposition of water for hydrogen evolution. In this study, amorphous tungsten phosphosulphide nanoparticle (WPS NP)-modified CdS (WPS/CdS) catalysts were successfully prepared by a simple physical mixing method. The activity of the 15% WPS/CdS composite catalyst is the best, and the average hydrogen production rate reached 123 257 µmol g-1 in 5 h, and the highest AQE of 9.15% is derived at 420 nm for the 15% WPS/CdS composite catalyst. Simultaneously, five cycle stability tests were performed on the 15% WPS/CdS composite catalyst, and the results show that the 15% WPS/CdS composite catalyst exhibits a high stability. WPS NPs not only improve the visible light absorption rate, but also provide a large number of exposed active sites for the hydrogen evolution reaction. These active sites can capture photogenerated electrons on CdS NRs quickly, and can be used for the hydrogen evolution reaction quickly, promoting the transmission and separation of photogenerated charges and inhibiting the recombination of photogenerated electron and hole pairs. Thus, the utilization rate of photogenerated electrons generated by visible light is improved, and the activity of the photocatalyst is significantly increased.
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The photocatalytic decomposition of water to produce hydrogen is an important strategy to effectively utilize solar energy and solve the energy crisis. In this study, a highly efficient WP-nanoparticle-modified composite catalyst was successfully prepared. WP nanoparticles have been used as an efficient and acid-stable co-catalyst for the HER owing to their specific electronic structure, metalloid characteristics and catalytic activity. On the one hand, the octahedral spatial structure of UiO-66 not only provides attachment space for CdS and WP nanoparticles, but also effectively reduces the particle size and increases the dispersion of CdS and WP nanoparticles. On the other hand, the potential difference and the matching energy band positions of UiO-66 and CdS provide a feasible thermodynamic path for the transmission of photogenerated electrons. The intimate contact between the abovementioned three compounds resulted in a strong synergistic effect, which improved the efficiency of the photocatalytic H2 production. Under visible-light irradiation, the maximum H2 production in 5 h over the [UiO-66@CdS/WP (10 wt%)] photocatalyst was 395 µmol, which was 26.33 times that of pure CdS. The physical and chemical information of the samples could be obtained through XRD, SEM, TEM, XPS, BET and UV-vis DRS characterizations. Furthermore, based on the photoluminescence spectra, photoelectrochemical experiments and Mott-Schottky curves, we could reasonably explain the separation and transfer mechanisms of the photogenerated electrons and holes. The lower recombination rate of charge, enhanced intensity of light absorption, a short fluorescence lifetime (2.11 ns), a faster electron injection rate (KET = 2.32 × 108 s-1), a larger efficiency of electron injection (ηinj = 49.1%), high photocurrent response, and smaller charge transfer resistance accelerate the efficient separation and transfer of spatial charges, finally enhancing the photocatalytic performance.
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In the present study, we have successfully synthesized a kind of high-efficiency NiCo2O4/CdS composite photocatalyst using the hydrothermal method and high-temperature calcination. With the addition of NiCo2O4, hydrogen evolution has been significantly improved by successfully adjusting the electron transport routes. For the composite catalyst, the maximum amount of hydrogen evolution under visible light irradiation for 5 hours reached 549 µmol. Through this phenomenon, the hydrogen production rate of the corresponding composite catalysts reached 10 980 µmol g-1 h-1. The hydrogen production rate of the composite catalysts is 5.1 times that of pure CdS under the same conditions. In addition, there was no significant decrease in the photocatalytic activity of the composite catalyst even after 5 cycles of photocatalytic hydrogen production. These phenomena indicate that the introduction of NiCo2O4 inhibits the photo-corrosion of CdS itself and enhances hydrogen production activity while ensuring the stability of the catalyst. In order to characterize the physical properties of the NiCo2O4/CdS composite catalyst, we used XRD, SEM, TEM, XPS, BET and UV-vis techniques. In photoelectron and hole transport mechanisms, we have studied the catalysts by photoluminescence spectroscopy, transient photocurrent and photoelectrochemical experiments. The introduction of NiCo2O4 increases the active site of the composite catalyst, which facilitates the separation of photogenerated electrons and holes and accelerates the transfer of electrons.
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As light-emitting diodes (LEDs) become dominating solutions in general lighting, their applications are also penetrating into biomedical engineering, especially light therapies. These new applications usually require much higher light power density at a shorter working distance than general lighting. Besides the high power, uniformity in power distribution is another important factor in such applications to illuminate samples with equal irradiance. These factors require designing a compact optical system to transmit light from a highly integrated high-power LED light source. While existing designs mainly focus on providing the desired illuminance in a much larger target space, little work has been devoted to the optical design to achieve a high irradiance that is uniformly distributed onto a target area at a short distance away from the light source. This work proposes a design method to solve such a problem, based on a highly integrated LED module, a mixing rod, and a pair of aspheric lenses. Both numerical simulations and experiments with a prototype are performed, which have verified the effectiveness of the proposed method.
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Recent data strongly suggest the important role of miRNAs in various cancer-related processes. Osteosarcoma (OS) is the most common primary cancer of the bone and usually leads to deaths due to its rapid proliferation and metastasis. Here, we demonstrated that compared with noncancerous bone tissues, miR-135b expression is frequently upregulated in OS specimens, inversely correlated with potential target-FOXO1 expression pattern. Bioinformatics analysis combined with experimental confirmation revealed FOXO1 is a direct target of miR-135b in OS. Functionally, miR-135b inhibitor significantly inhibited OS cells proliferation and invasion. Forced expression of FOXO1 showed the opposite effect, and FOXO1 knockdown abolished the effect of miR-135b inhibitor. Taken together, our data provide compelling evidence that miR-135b functions as an onco-miRNA in OS to promote OS cells proliferation and invasion, and its oncogenic effects are mediated chiefly through targeting FOXO1.
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Fatores de Transcrição Forkhead/genética , MicroRNAs/biossíntese , Osteossarcoma/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/biossíntese , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , Invasividade Neoplásica/genética , Osteossarcoma/patologiaRESUMO
Utilizing the design of heterojunction structures formed between photocatalysts to enhance photoelectrochemical performance represents an effective strategy for improving the efficiency of photocatalytic hydrogen production. In this work, a straightforward one-step solvothermal method was employed to embed NENU-5 nano-octahedra within ZnIn2S4 nanoflowers, forming ZnIn2S4@NENU-5 heterostructures. Hydrogen production tests conducted over 5 h revealed a hydrogen evolution activity of 5282.14 µmol g-1 h-1 in triethanolamine (TEOA) solution at pH = 9, which is 4.9 times and 264 times higher than that of pure ZnIn2S4 and NENU-5, respectively. The significant enhancement in the photocatalytic performance indicates that the constructed Z-scheme heterojunction increases the active sites on the catalyst surface and plays a crucial role in photocarrier transfer. Furthermore, the formation of the Z-scheme heterojunction is confirmed through Mott-Schottky (M-S) analysis, ultraviolet photoelectron spectroscopy (UPS), and valence band X-ray photoelectron spectroscopy (VB-XPS). The effective charge transfer at the ZnIn2S4@NENU-5 heterojunction interface is validated based on X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) analysis, and density functional theory (DFT) calculations. In summary, this work offers an effective approach to designing novel heterojunction photocatalysts by combining MOF materials with bimetallic sulfides, thereby promoting the efficiency of photocatalytic hydrogen production.