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In situ synthesis of Z-scheme BiPO4/BiOCl0.9I0.1 heterostructure with multiple vacancies and valence for efficient photocatalytic degradation of organic pollutant
摘要： Design and construction of Z-scheme photocatalyst has been attracted much attention, which is a great challenge to develop highly efficient photocatalyst without the external redox mediators. Herein, a novel efficient redox-mediator-free Z-scheme BiPO4/BiOCl0.9I0.1 heterojunction is synthesized in situ via a mild 90℃ water bath reaction. The as-synthesized BiPO4/BiOCl0.9I0.1 heterostructure exhibits outstanding photocatalytic performance for degradation of phenol and Rhodamine B, approximately 2.6 and 4.3 times higher than that of BiOCl0.9I0.1, respectively. The BiPO4/BiOCl0.9I0.1 heterostructure have multiple vacancies and valence, such as Bi5+, Bi3+, Bi(3-x)+, I-, I3-, and IO3-, which could facilitate the charge separation and transfer in the photocatalytic process. The higher photocatalytic activity of redox-mediator-free Z-scheme BiPO4/BiOCl0.9I0.1 heterostructure could be attributed to the strong redox ability, multiple charge transfer channels via the various defects, and tight contact due to in situ synthesis. The finding provides some new insights for the design of effective direct Z-scheme photocatalyst with multiple defects.
关键词： direct Z-scheme heterojunction,photocatalysis,BiOCl0.9I0.1/BiPO4,redox-mediator-free,multiple defects
更新于2025-09-04 15:30:14
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Fabrication of highly efficient and hierarchical CdS QDs/CQDs/H-TiO2 ternary heterojunction: Surpassable photocatalysis under sun-like illumination
摘要： Highly efficient and durable visible-light utilized nanocomposites have a vital role in environmental pollutants remediation. Hence, in this study, we have fabricated CdS QDs co-sensitized CQDs/H-TiO2 (Hollow Titania) ternary heterostructures (CdS QDs/CQDs/H-TiO2) in a facile region-selective deposition route. The as-fabricated nanocomposites were evidently characterized by physicochemical techniques. CdS QDs were uniformly distributed on the smooth surface of hierarchical CQDs/H-TiO2 heterojunction. The as-fabricated CdS QDs/CQDs/H-TiO2 nanocomposite has high-performances for efficient degradation efficacy of phenol, MB and RhB which exhibited enhanced degradation activities with rate constants (k) of 0.03, 0.051 and 0.045 min-1, respectively. All these superior photocatalytic activities obviously attributed to the effect of calcination temperature, enhanced photocurrent, minimized recombination of photo-induced charges in the photocatalysis and optimum content of CdS QDs have the distinct basis for the close interfacial connection developing. In addition, evidenced on the arguable results of electron spin resonance and radical-trapping experiments, the primary reactive-oxygen species and a plausible reaction-mechanism for organic pollutants degradation over CdS QDs/CQDs/H-TiO2 were proposed. This creative work is strategically considered an important step to potentially enhance the utilization of TiO2 in various fields as visible light-induced heterojunction.
关键词： Hollow TiO2,CdS QDs/CQDs/H-TiO2,Visible-light photocatalysis,CQDs/H-TiO2,Environmental remediation
更新于2025-09-04 15:30:14
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Fabrication of Perylene Tetracarboxylic Diimide-Graphitic Carbon Nitride Heterojunction Photocatalyst for Efficient Degradation of Aqueous Organic Pollutants
摘要： Metal-free g-C3N4 is the promising candidate for the next generation visible light-responsive photocatalyst, however, high recombination probability of the photogenerated charge carriers on g-C3N4 limits its photocatalytic activity. To further increase the intrinsic photocatalytic activity of g-C3N4, here perylene tetracarboxylic diimide-g-C3N4 heterojunctions (PDI/GCN) are prepared by one-step imidization reaction between perylene tetracarboxylic dianhydride (PTCDA) and g-C3N4 in aqueous solution. By the combination of various testing results it is confirmed that the surface hybridization of PTCDA and g-C3N4 in the PDI/GCN heterojunctions via O=C?N?C=O covalent bonds occurs at lower PTCDA-to-g-C3N4 weight percentage. By selecting p-nitrophenol and levofloxacin as the target organic pollutants, the visible light photocatalytic performance of the PDI/GCN heterojunctions are studied. It shows that the PDI/GCN heterojunction prepared at PTCDA-to-g-C3N4 weight percentage of 1% exhibits remarkably higher visible light photocatalytic degradation and mineralization ability towards aqueous target pollutants as compared with g-C3N4 and Degussa P25 TiO2. On the basis of the experimental results including photoelectrochemistry, indirect chemical probe and electron spin resonance spectroscopy it is verified that the surface hybridization in the heterojunctions is responsible for this enhanced photocatalytic activity via accelerating the migration and separation of the photogenerated charge carriers, causing to produce more active species like ?O2?, hVB+ and ?OH for deep oxidation of PNP or LEV to CO2 and inorganic anions.
关键词： graphitic carbon nitride,heterojunction,perylene tetracarboxylic diimide,visible light photocatalysis,organic pollutant
更新于2025-09-04 15:30:14
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3D reticulated carbon nitride materials high-uniformly capture 0D black phosphorus as 3D/0D composites for stable and efficient photocatalytic hydrogen evolution
摘要： Black phosphorus has recently emerged as an excellent 2D semiconductor with high charge-carrier mobility and wide tunable bandgap for photocatalysis. In the research, a simple method was developed to manufacture reticulated carbon nitride materials (CN-4N). Utilizing the self-capturing property of CN-4N to catch the black phosphorus quantum dots (BQ) that were uniformly dispersed in aqueous solution, the BQ were successfully implanted into the interior surface of CN-4N, to form a unique structure instead of the normal exterior surface contact pattern. The optimized CN-4N(BQ) showed good stability and achieved an excellent hydrogen production rate of 13.83 mmol h?1 g?1, which was is 3.3 and 35.5 folds larger than that of CN-4N and bulk CN (NCN), respectively. The experimental results illustrated that greatly improved photocatalytic performance of CN-4N(BQ) was attributed to the joint actions of the abundant active sites provided by ultra-porous structures, the excellent vis-NIR absorption capability, the spatially separated reactive sites for the redox reaction, and the greatly enhanced photoinduced electron-hole separation efficiency. This research provides a novel insight for the rational fabrication of CN-based hybrids for various applications.
关键词： Black phosphorus,carbon nitride,photocatalysis,quantum dots,hydrogen evolution
更新于2025-09-04 15:30:14
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Semiconductor Heterojunctions for Enhanced Visible Light Photocatalytic H2 Production
摘要： Semiconductor-based heterojunctions have been shown to be effective photocatalytic materials to overcome the drawbacks of low photocatalytic efficiency that results from a high rate of electron?hole recombination and narrow photo-response range. In this paper, we report on the study of heterojunctions made from visible light active, graphitic carbon nitride, g-C3N4), and UV light active, strontium pyroniobate, Sr2Nb2O7. Heterojunctions made from a combination of g-C3N4 and nitrogen-doped Sr2Nb2O7 obtained at different temperatures were also studied to determine the effect of N doping. The photocatalytic performance was evaluated by using photocatalytic hydrogen evolution reaction (HER)from water g under visible light irradiation. It was found that the photocatalytic activities of as prepared heterojunctions are significantly higher than that of individual components under similar conditions. Heterojunction formed from g-C3N4 and N-doped Sr2Nb2O7 at 700oC (CN/SNON-700) showed better performance than heterojunction made from g-C3N4 and Sr2Nb2O7 (CN/SNO). A plausible mechanism for the heterojunction enhanced photocatalytic activity is proposed based on, relative band positions, and photoluminescence data.
关键词： graphitic carbon nitride,visible light photocatalysis,strontium pyroniobate,Semiconductor heterojunctions,hydrogen production
更新于2025-09-04 15:30:14
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Nanostructured Anodic Oxides: Fabrication & Applications
摘要： The special issue of Current Nanoscience entitled “Nanostructured Anodic Oxides: Fabrication & Applications” comprises review papers focused on various aspects of these nanostructures. Nanostructured anodic oxides are awaking high hopes in the research community due to the solutions of emerging problems they offer. Classically, the anodic oxides on aluminum and its alloys are a protective coating, providing improved corrosion resistance [1-5], adhesion of primer to metallic substrate [6] and hardness of the anodized surface [7-10]. However, since two-step self-organized anodization was invented in 1995, allowing to form highly-ordered honey-comb ordering of the nanopores (Fig. 1a), numerous researches have been triggered. On one hand, still new electrolytes, operating conditions and electrolyte additives are being researched, providing new ranges of the applied voltages and consequently new ranges of oxides pore diameter and interpore distance [11-17]. On the other hand, research on anodic aluminum oxide is so mature, that already significant achievements in nanofabrication [18-22] (Figs. 1b-1c), surfaces with tunable wetting angle [23-27], cells culturing platforms [28, 29], biomaterials performance [29], sensing [30, 31], structural color generation [31, 32], photocatalysis [33], renewable energy harvesting [34-36], photonic crystals [37] and plasmonic materials [38] have been reported. Moreover, also other metals are being researched. Numerous achievements in anodization of Ti [39-45] W [46], Zr [47, 48], Cu [49-51], Fe [52], Sn [53], Zn [54] and stainless steel [55] allowed to make progress in renewable energy harvesting [43, 44, 51] (especially in the assembly of dye-sensitized solar cells [44] and photoelectrochemical water splitting [43, 51]), CO2 reduction to hydrocarbons [45], drug delivery systems [41], improvement in biomaterials performance [40] and photocatalysis [46]. Moreover, also intermetallic alloys, like FeAl [56, 57] and bimetallic, layered systems like Al-Ti [58] were anodized in order to form nanoporous oxides with tunable band gap and to ease the nanofabrication, respectively.
关键词： Nanostructured Anodic Oxides,Biomaterials,Anodization,Renewable Energy Harvesting,Photocatalysis,Sensing,Fabrication,Applications,Nanofabrication
更新于2025-09-04 15:30:14
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Silicon-grafted Ag/AgX/rGO nanomaterials (X = Cl or Br) as dip-photocatalysts for highly efficient p-nitrophenol reduction and paracetamol production
摘要： In this work, plasmonic Ag/AgX/rGO (X = Cl or Br) nano‐photocatalysts were grafted with silicon by adding trimethylsilyl chloride as silicon precursor. The synthesized Ag/AgX/rGO‐Si hybrids showed a large improvement of photocatalytic activity towards the synthesis of p‐aminophenol (PAP) as well as paracetamol (acetaminophen; APAP) through the photoreduction of p‐nitrophenol (PNP). The prepared catalysts Ag/AgX/rGO were characterized using SEM, XRD, FTIR and the reduction reaction of p‐nitrophenol was monitored by UV–Vis measurements, GC/MS and 1HNMR data. From the results, it was demonstrated that the rate order of reduction process of the PNP to PAP and to APAP under visible light irradiation of the samples was as follows; Ag/AgBr/rGO‐Si > Ag/AgCl/rGO‐Si > Ag/AgBr/rGO > Ag/AgCl/rGO. The reaction mechanism had been postulated that was supported with the spectroscopic data. In addition, the catalysts were recovered from the reaction medium and re‐used in three cycles that indicated the reusability and stability of the catalysts. This study was featured by the following; i) fast reaction, ii) the reduction of p‐nitrophenol to paracetamol was performed in a facile one‐pot reaction compared to previous approaches that tends to reduce the production cost, and iii) investigations on the catalytic properties of Ag/AgX/rGO in organic transformations open the door to find a benefice of these catalysts in other organic reactions and in the development in the synthesis of pharmaceutical products.
关键词： reduced graphene oxide,Ag/AgX nanocomposites,P‐aminophenol,photocatalysis,paracetamol
更新于2025-09-04 15:30:14
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Performance Characteristics of a suspended Catalyst Oscillatory Membrane Photocatalytic Reactor
摘要： The performance characteristics of an oscillatory membrane photocatalytic reactor is investigated using dye degradation over suspended ZnO catalyst as a model reaction. Both flat surface membranes and ones with transverse turbulence promoters (TP) were used. The results showed that application of oscillatory motion can be effective in enhancing the performance of suspended catalyst membrane photocatalytic reactors. It also showed that the eddy formation and vortex shedding when using membranes with TP gave rise to several synergistic effects. First, it provided effective removal of catalyst deposits from the membrane surface which enhanced the flux. Second, it increased the suspended catalyst fraction in solution which consequently enhanced the reaction rate. Third, it provided effective mixing in the reaction channel that minimized particles sedimentation and agglomeration, which further enhanced the catalyst suspension and increased its effective reaction area. The specific energy consumption (kWh/m3) was found to compares favourably to a membrane cross flow filtration system. This, and when added to the smaller footprints of the oscillatory design configuration, could make the latter an attractive option for confined space applications. Such advantages however must be assessed in light of the design and maintenance requirements of the oscillatory mechanism in comparison to a conventional cross flow filtration membrane system.
关键词： Oscillatory motion,Photocatalysis,Membrane
更新于2025-09-04 15:30:14
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Novel and inexpensive Nb2O5/tannin-formaldehyde xerogel composites as substitutes for titanium dioxide in photocatalytic processes
摘要： This project studied the preparation of new Nb2O5/tannin-formaldehyde xerogel composites (XTF-wNb) for photocatalytical applications. The choice of tannin biomass and niobium recycled scraps as precursors is aimed at reducing costs and environmental impacts. The composites were characterized by diffuse re?ectance spectroscopy (DR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), infrared spectroscopy (IR), and X-ray diffraction (XRD). The photocatalytic properties of the composites were evaluated by methylene blue decomposition. The in?uence of the catalyst dosage and the initial concentration of dye in the adsorption and photocatalysis processes were studied. The X-ray pro?les of the XTF-wNb show the presence of niobic acid in the structure of the materials, proving the presence of the inorganic oxide in the matrix of these composites. The tannin/Nb ratio had a signi?cant in?uence on the morphology of the formed composites, causing changes in the shape and size of the particles composing each material. All materials have pHPZC < 5. The XTF-24Nb was the most effective photocatalyst, its photocatalytic ef?ciency superior to the one of titanium dioxide, evidencing the bene?cial effect of the xerogel coupling on the photocatalytic properties of the material.
关键词： Photocatalysis,Niobium oxide,Xerogel,Tannin
更新于2025-09-04 15:30:14
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Carbon nanosheet facilitated charge separation and transfer between molybdenum carbide and graphitic carbon nitride toward efficient photocatalytic H2 production
摘要： Interfacial manipulation of nanostructured heterojunction photocatalysts to enhance charge separation and transfer is highly desirable to achieve a high photocatalytic activity. In this work, a well-designed non-noble-metal Mo2C@C/g-C3N4 heterostructure is constructed, in which the intercalated carbon nanosheets serve as a binder to form an excellent interfacial contact between Mo2C and g-C3N4. In addition, large quantities of carbon quantum dotsare found to be homogeneously embedded in the carbon nanosheets. The as-obtained Mo2C@C/g-C3N4 hybrid exhibits a remarkably improved photocatalytic H2 evolution rate of 52.1 μmol h?1 under visible-light irradiation (λ ≥ 420 nm) without co-catalyst, which is up to nearly 260 times higher than that of pristine g-C3N4 (0.2 μmol h?1) under the same conditions. The significant increase in photocatalytic activity mainly results from the fast charge migration and separation between Mo2C and g-C3N4 facilitated by the conducting carbon nanosheets as an efficient electron mediator. Moreover, the carbon quantum dots embedded in the carbon support also promotes solar energy utilization. This work highlights a feasible strategy to explore highly efficient photocatalysts via interfacial engineering on heterojunction composites.
关键词： H2 evolution,Photocatalysis,Water splitting,Carbon nitride,Heterojunction
更新于2025-09-04 15:30:14