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Enhancing the performance of pollution degradation through secondary self-assembled composite supramolecular heterojunction photocatalyst BiOCl/PDI under visible light irradiation
摘要： A novel n-n type inorganic/organic heterojunction of flaky-like BiOCl/PDI photocatalyst was constructed by water bath heating method. Meanwhile, a simple method - secondary self-assembly was used to prepare the BiOCl/PDI with a special band structure. The photocatalytic activities were evaluated by degrading aqueous organic pollutants under visible light (λ > 420 nm). The removal rates of 5 mg L?1 phenol (non-ionic type), methyl orange (MO, anionic type), rhodamine B (RhB, cationic type) and 10 mg L?1 RhB by secondary self-assembly BiOCl/PDI (BiOCl/PDI-2) were 8.0%, 3.4%, 27.8% and 78.9% higher than self-assembly BiOCl/PDI (BiOCl/PDI-1) under visible light (λ > 420 nm). The better photocatalytic activity for BiOCl/PDI-2 was attributed to the optimization of energy-band structures, which arose from different exposed surfaces, narrower interplanar spacing and stronger visible light absorption performance. Under acidic condition, BiOCl/PDI-2 showed a good photocatalytic activity, which was not affected by neutral ionic intensity and had good recycling properties. Moreover, the photocatalytic mechanism was explored by free radical capture test and electron paramagnetic resonance (EPR), and contribution of active species was calculated. The main active species of BiOCl/PDI-2 were ?O2?, 1O2 and h+. Our work may provide a route to design efficient inorganic/organic heterojunctions for organic pollutants degradation.
关键词： Supramolecular,Visible light photocatalysts,Perylene diimide,BiOCl,Heterojunction
更新于2025-09-23 15:19:57
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Xanthene Dye-Functionalized Conjugated Porous Polymers as Robust and Reusable Photocatalysts for Controlled Radical Polymerization
摘要： Photoinduced electron/energy transfer?reversible addition?fragmentation chain transfer (PET?RAFT) polymerization represents a versatile and highly e?cient method for polymerizations of wide-ranging monomer variances upon solar energy harvesting. Although signi?cant progress has been achieved, several drawbacks are still associated with existing photocatalysts, such as toxicity of transition metals, high cost, poor stability, and unavoidable puri?cation procedures because of the photobleaching e?ect, to name a few. Herein, 1,4-diethynylbenzene-linked xanthene dye-conjugated porous polymers (CPPs) have been established as potential heterogenous photocatalysts of PET?RAFT polymerization. With this two-dimensional planar architecture, we demonstrate dual-stimuli toggling of RAFT polymerization using two di?erent external physical manipulations: light “ON”/“OFF” and solution pH “LOW”/“HIGH”. In addition, these CPPs endowed radical polymerizations with various impressive features such as compatibility of diverse monomer formulations, unique oxygen tolerance, and ppm-level catalyst dosage. Demonstrations of chain extension and catalyst recycling further highlight the robustness and performance of this CPP catalyst. Through the study of structure?property relationship using the experimental analyses, we envisage that a series of xanthene dye-functionalized CPPs can be developed as visible light-absorbing organocatalysts rivaling transition-metal photocatalysts.
关键词： PET?RAFT polymerization,visible light-absorbing organocatalysts,xanthene dye-functionalized conjugated porous polymers,dual-stimuli toggling,heterogeneous photocatalysts
更新于2025-09-23 15:19:57
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De-Ethylation and Cleavage of Rhodamine B by a Zirconium Phosphate/Silver Bromide Composite Photocatalyst
摘要： A composite heterogeneous photocatalyst based on silver bromide was prepared by a reaction of silver exchanged zirconium phosphate (ZrP) and HBr. The ZrP/AgBr composite containing 53 wt% AgBr was tested in the photocatalytic degradation of Rhodamine B (RhB) and exhibited higher catalytic activity with respect to pure AgBr. As a matter of fact, the time needed to achieve a percentage of chromophore cleavage of about 90% was 3 min for the composite versus the 30 min needed for pure AgBr. The ZrP/AgBr composite turned out to be stable for at least three consecutive cycles. The UV-Vis spectra of the RhB solution, recorded at different irradiation times, were also decomposed and the concentration of the species formed by de-ethylation and cleavage processes during photocatalysis were calculated; the data obtained for the AgBr-based catalysis were also compared with those for the AgCl-based catalysis, and the degradation mechanism was suggested for both catalytic systems.
关键词： photocatalysts,zirconium phosphate,Rhodamine B,silver halides
更新于2025-09-19 17:15:36
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Iron and the other metal species as phase-composition controllers the photocatalytic activity of TiO2 materials
摘要： The goal of the work is to verify which properties of TiO2-based materials, influenced by small amounts of Fe, Co, Ga, Bi, W, Mo, V and Ni species used as modifiers, play the predominant role in changing the photoactivity of TiO2. Two groups of materials were studied: TiO2 synthesized in the presence of nanocrystalline metal oxide and dissolved metal ions (cations or oxyanions). Sols were calcined at 450, 600 or 900°C. Physicochemical properties of the materials were characterized by XRD, DRS, SEM, EPR, porosimetry and photocurrent measurements. The most detailed studies were focused on modifications by iron species. TiO2 doping was achieved for both Fe3+ and Fe2O3 modifiers after calcination at temperatures equal to or higher than 450 and 900°C, respectively. Morphology of the materials (phase composition, specific surface area, etc.) were influenced by iron species even if they were not introduced into the crystal lattice of TiO2. Comparison of activity of photocatalysts and elucidation of the role of various reactive oxygen species were based on photooxidation tests involving Azure B and terephthalic acid. In general, iron species improved photocatalytic activity, nevertheless, doping of the materials appeared detrimental. A particular improvement of the activity was achieved for composites with low iron contents (ca. 0.01%mol Fe:Ti). The studies revealed, that beside the widely discussed mechanisms (photo-Fenton processes, charge separation, photosensitization, etc.) iron species can indirectly influence the photocatalytic activity of TiO2 acting as phase-composition controllers (PCC) during the synthesis of this oxide, which determine morphology of the resulting photocatalyst. To support this hypothesis, several sets of other TiO2 materials were modified with Co, Ga, Bi, W, Mo, V and Ni species. We show, that the use of these modifiers in small amounts can influence indirectly the activity of photocatalysts regardless to the type of modifier. Therefore different photoactivity of the tested materials should be attributed rather to these modifier-induced structural and electronic changes of the photocatalysts than to any other function of dopants, including photosensitization, enhanced charge separation, catalytic activity, at which most of studies are focused.
关键词： phase composition,photocatalysis,synthesis of photocatalysts,modified titanium dioxide
更新于2025-09-19 17:15:36
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Few-cycle laser driven reaction nanoscopy on aerosolized silica nanoparticles
摘要： Nanoparticles offer unique properties as photocatalysts with large surface areas. Under irradiation with light, the associated near-fields can induce, enhance, and control molecular adsorbate reactions on the nanoscale. So far, however, there is no simple method available to spatially resolve the near-field induced reaction yield on the surface of nanoparticles. Here we close this gap by introducing reaction nanoscopy based on three-dimensional momentum-resolved photoionization. The technique is demonstrated for the spatially selective proton generation in few-cycle laser-induced dissociative ionization of ethanol and water on SiO2 nanoparticles, resolving a pronounced variation across the particle surface. The results are modeled and reproduced qualitatively by electrostatic and quasi-classical mean-field Mie Monte-Carlo (M3C) calculations. Reaction nanoscopy is suited for a wide range of isolated nanosystems and can provide spatially resolved ultrafast reaction dynamics on nanoparticles, clusters, and droplets.
关键词： ethanol,water,SiO2 nanoparticles,photocatalysts,nanoparticles,Mie Monte-Carlo calculations,momentum-resolved photoionization,reaction nanoscopy,near-fields
更新于2025-09-19 17:13:59
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Robot path planning with two-axis positioner for non-ideal sphere-pipe joint welding based on laser scanning
摘要： The conversion and degradation of organic pollutants remain challenges relating to environmental science. Herein, we report the carbonization of organic pollutants (4-nitrophenol, 4-NP) toward metal-free nitrogen-doped graphene quantum dots (N-GQDs) using a one-pot solvothermal route. The resultant N-GQDs demonstrate excellent activity for the catalytic conversion of 4-NP to 4-aminophenol (4-AP) when exposed to near infrared (NIR) light because of their excellent upconverted photoluminescence and photothermal conversion ability. The NIR-enhanced reduction efficiency of 4-NP to 4-AP not only originates from the enhanced collisions between N-GQDs and 4-NP due to photothermal-increased Brownian movement of molecules, but also comes from the accelerated transfer rate of electrons produced by the photoexcitation of N-GQDs under NIR irradiation. The N-GQDs display excellent photostability and remain high activity even after five cycles of reuse. Such conversion of organic pollutants to highly efficient metal-free carbocatalysts has significant importance in relevance of the industrial production of aniline and paracetamol.
关键词： organic pollutants,metal-free photocatalysts,4-nitrophenol reduction,nitrogen-doped graphene quantum dots,NIR-enhanced catalytic activity
更新于2025-09-19 17:13:59
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One-pot synthesis of Mn3O4-coupled Ag2WO4 nanocomposite photocatalyst for enhanced photooxidative desulfurization of thiophene under visible light irradiation
摘要： The photooxidative desulfurization of thiophene (ThP) becomes a challenge in both industry and environmental remediation. Herein, we synthesize a visible-light-responsive Ag2WO4/Mn3O4 nanocomposite by a one-pot strategy. Depiction of the produced photocatalysts exposed the suppression of the surface structure and reduction of the bandgap energy by adding 15 wt% of Mn3O4 to Ag2WO4. The obtained nanocomposite shows a complete photooxidation of ThP within 1 h under visible light illumination at a dose of 1.2 g L?1. The significance of photocatalytic performance of Ag2WO4/Mn3O4 nanocomposite photocatalyst is referred to the enhancement of the visible light absorption and overthrow of the recombination of photogenerated charge carriers. The study opens the door for extensive use of nanocomposite photocatalysts as a novel functional material for the photooxidation of ThPs under visible light exposure.
关键词： Desulfurization,Photooxidation,Thiophene,Nanocomposite,Photocatalysts,Visible light
更新于2025-09-16 10:30:52
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The synthesis of Co <sub/>x</sub> Ni <sub/>1?x</sub> Fe <sub/>2</sub> O <sub/>4</sub> /multi-walled carbon nanotube nanocomposites and their photocatalytic performance
摘要： A series of CoxNi1?xFe2O4/multi-walled carbon nanotube (CoxNi1?xFe2O4/MWCNTs) nanocomposites as photocatalysts were successfully synthesized, where CoxNi1?xFe2O4 was synthesized via a one-step hydrothermal approach. Simultaneously, methylene blue (MB) was used as the research object to investigate the catalytic effect of the catalyst in the presence of hydrogen peroxide (H2O2). The results showed that all the photocatalysts exhibited enhanced catalytic activity compared to pure ferrite. In addition, compared with the other photocatalysts, the reaction time was greatly shortened a significantly higher removal rate was achieved using 3-CNF/MWCNTs. There was no significant decrease in photodegradation efficiency after three catalytic cycles, suggesting that CoxNi1?xFe2O4/MWCNTs are recyclable photocatalysts for wastewater treatment. Our results indicate that the CoxNi1?xFe2O4/MWCNT composite can be effectively applied for the removal of organic pollutants as a novel photocatalyst.
关键词： methylene blue,photocatalysts,hydrothermal approach,wastewater treatment,multi-walled carbon nanotube,hydrogen peroxide,CoxNi1?xFe2O4
更新于2025-09-16 10:30:52
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Synthesis of Au-decorated three-phase-mixed TiO <sub/>2</sub> /phosphate modified active carbon nanocomposites as easily-recycled efficient photocatalysts for degrading high-concentration 2,4-DCP
摘要： It is of great significance to fabricate easily-recycled TiO2 photocatalysts with high activity. Herein, dominant-anatase three-phase (anatase/rutile/brookite)-mixed nanosized TiO2 with high photocatalytic activity for degrading a high-concentration of 2,4-DCP has been synthesized via a hydrothermal process with HCl as a phase-directing agent, and interestingly the apparent photoactivity could be greatly improved by decorating Au nanoparticles and then coupling phosphate-treated active carbon. The amount-optimized nanocomposite displays (cid:1)12-fold enhancement in degradation rate constant (k) compared to anatase TiO2. Based on the steady-state surface photovoltage spectra, fluorescence spectra related to the produced $OH amount, temperature-programmed desorption and O2 electrochemical reduction curves, it is confirmed that the exceptional photoactivity is mainly attributed to the greatly-enhanced charge separation from the phase-mixed composition, and from the decorated Au as electron acceptors and its promotion effects on O2 activation. Moreover, the use of phosphate-modified AC as a support is also positive for efficient photocatalytic reactions by accepting electrons and concentrating the pollutants, with recyclable features. This work provides a feasible strategy to fabricate TiO2-based nano-photocatalysts for degrading high-concentration pollutants to remediate the environment.
关键词： 2,4-DCP degradation,photocatalysts,Au nanoparticles,TiO2,active carbon
更新于2025-09-16 10:30:52
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Soft-chemistry assisted strong metal-Support interaction on designed plasmonic core-shell photocatalyst for enhanced photocatalytic hydrogen production
摘要： Engineering photocatalysts based on gold nanoparticles (AuNPs) has attracted great attention for the solar energy conversion due to their multiple and unique properties. However, boosting the photocatalytic performance of plasmonic materials for H2 generation have reached some limitation. In this study, we propose a soft-chemistry method for the preparation of strong metal-interaction support (SMSI) to enhance the photocatalytic production of H2. The TiO2 thin overlayer covering finely dispersed AuNPs (forming an SMSI) boost the photocatalytic generation of hydrogen, compared to AuNPs deposited at the surface of TiO2 (labelled as a classical sytem). The pathway of the charge carriers’ dynamics occurred regarding the system configuration are found to be different. The photogenerated electrons are collected by AuNPs in a classical system and act as an active site, while, unconventionally, they are injected back in the titania surface for an SMSI photocatalyst making the system highly efficient. Additionally, the adsorption energy of methanol, theoretically estimated using density functional theory (DFT) methodology, is lower for soft-chemistry SMSI photocatalyst accelerating the kinetics of photocatalytic hydrogen production. SMSI obtained by soft-chemistry is an original concept for highly efficient photocatalytic materials, where the photons-to-energy conversion remains a major challenge.
关键词： hydrogen production,photocatalysts,solar energy conversion,gold nanoparticles,TiO2,SMSI
更新于2025-09-16 10:30:52