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An investigation on electroless nickel coating on yttria stabilized zirconia nanoparticles via single step surface activation methods
摘要： Metal coated ceramic nanopowders have a considerable potential for many fields of applications. Here, electroless coating of pure nickel onto yttria-stabilized zirconia nanoparticles is studied. We introduce a single step method to activate ceramic nanoparticles surface to reduce complexities of electroless coating on ceramic nanoparticles by conventional double step pre-treatments. X-ray diffraction and electron diffraction patterns beside transmission electron microscopy images are used to analyze the coated nanoparticles. We observe that palladium hydroxide acts as a catalyst for electroless nickel reaction like palladium and the ceramic nanopowders surface is effectively activated for electroless reaction by simpler single step activation methods. Atomic absorption spectroscopy results show that the performance of electroless reaction is not enhanced by increase in catalyst amount. Also, relative changes in amount of deposited nickel are investigated via magnetization curves of the coated particles. The vibrating sample magnetometery results demonstrate the magnetic behavior of the processed particles can be modified by deposited nickel amount.
关键词： Catalysis,Nickel,coating,Palladium,Electroless,YSZ nanopowder
更新于2025-09-09 09:28:46
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Halloysite based nanocomposites and photocatalysis: A Review
摘要： Heterogeneous photocatalysis is an e?cient, relatively cheap and environmentally friendly technology for decomposing various organic and air pollutants. Halloysite is a natural clay mineral usually in the form of nanotubes that has many applications as well as potential uses including photocatalysis. In this paper the photocatalytic activities of halloysite-based nanocomposites in combination with various photocatalysts that have been synthesized and tested in decomposing organic and air pollutants are reviewed. Many photocatalysts have been synthesized and among them TiO2 in the form of anatase, or rutile, or a mixture of both is the most common photocatalyst due to its e?ectiveness and low cost. Researches by many investigators are summarized and discussed. The possibilities and limitations of halloysite-based nanocomposites for future applications are also discussed and new ?elds of research are proposed. It is suggested that Halloysite-based nanocomposites are more promising in positively charged organic substrates like tetracycline and Rhodamine B where the organic pollutant is attracted by halloysite's negatively charged external surfaces close to the photocatalysts, than neutral like paracetamol or negatively charged which that attraction does not occur.
关键词： Azo dyes,Halloysite nanocomposite,Halloysite,TiO2,VOCs,Heterogeneous catalysis,Air pollutants,Photocatalysis
更新于2025-09-09 09:28:46
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Photoinduced Ligand-to-Metal Charge Transfer Enables Photocatalyst-Independent Light-Gated Activation of Co(II)
摘要： Photoredox catalysis can be used to manipulate the redox state of a transition metal complex leading to the desired reactivity. While powerful, obviating the role of the second catalyst would be attractive from the perspective of simplifying the protocol and using visible light to uncover unexpected, enabling reactivity. Herein we report that Co-acetylides, formed in situ, are photoactive complexes that undergo ligand-to-metal charge transfer using visible light. The net transformation uses air-stable Co(II) complexes as precatalysts and induces Co(I) chemistry. The acetylide is an electron reservoir forming the Co(I) but accepting the electron back at the end of the catalytic cycle. The electronic nature of the acetylide leads to either on?off behavior or simply initiates catalysis, depending on electronics.
关键词： light-driven,charge-transfer,cobalt catalysis,photoredox,cycloaddition
更新于2025-09-09 09:28:46
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Rapid Deposition of Photocatalytically Enhanced TiO<sub>2</sub> Film by Atmospheric SPPS Using Ar/N<sub>2</sub>-Vortex Plasma Jet
摘要： In this study, as cost effective and an environmentally friendly film deposition technology, Atmospheric Solution Precursor Plasma Spray (ASPPS) was utilized for the deposition of the photo-catalytic titanium oxide (TiO2) film for the fabrication process of photovoltaic devices for rural electrification in developing countries. In addition, ethanol-diluted titanium tetra-iso-butoxide (TTIB: Ti(OC4H9)4) was used as a feedstock. N2-dominant Ar/N2 was also utilized as plasma working gas as well as for the elevation of the thermal plasma energy. By controlling deposition distances and temperature, using vortex generation anode nozzle operated at 1 kW, photo-catalytic TiO2 film was deposited and its crystallinity was confirmed by X-ray diffraction. Besides, the photo-catalytic properties of the film were confirmed by the methylene blue decolorization and the surface wettability tests. Surface morphologies of the TiO2 film was evaluated using optical micrographs. Furthermore, the film thickness and strength were measured using micro screw gauge and pencil scratch tester respectively. Lastly, when this Photo-catalytic TiO2 film was applied to photovoltaic devices, the device generated an open circuit voltage of 146.7 mV with solar irradiance intensity of 574 W/m2. From these results it was confirmed that, the ASPPS technology equipped with high cooling efficiency vortex anode nozzle is available for deposition of TiO2 film for the fabrication process of low-cost photovoltaic devices for rural areas in developing countries.
关键词： renewable energy,titanium oxide,photovoltaic devices,photo-catalysis,dye sensitized solar cell,thermal spray
更新于2025-09-09 09:28:46
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One-Pot Synthesis of Magnesium Aminoclay–Iron Oxide Nanocomposites for Improved Photo-Fenton Catalytic Performance
摘要： Fe3O4 nanoparticles (NPs) have been widely used in photo-Fenton catalysis applications for water/waste water treatment. Their drawbacks, however, continue to limit their potential. In the present study, we synthesized magnesium aminoclay–iron oxide [MgAC–Fe3O4] nanocomposites in DI water solution by treated them under 4% H2/Ar for 3 hours in a 500 (cid:3)C furnace. Obtained X-ray diffraction (XRD) patterns con?rmed that the growth of the Fe3O4 NPs in the amorphous MgAC; also, scanning electron microscopy (SEM) images indicated that the MgAC–Fe3O4 nanocomposites were in an aggregated form of 170 ± 117 nm average-diameter. MgAC[0.7 g]–Fe3O4 nanocomposite exhibited the best photo-Fenton catalysis with methylene blue (MB) was completely removed from the treatment solution at a constant rate of 0.0083 (min?1(cid:2) on the batch scale. This performance was 13.83 times better than that of commercial Fe3O4. On the pilot scale (100 L), MgAC[0.7 g]–Fe3O4 nanocomposite took 12 hours to completely removed MB from tap water. The mechanism of the high photo-Fenton catalysis was attributed to the higher rate adsorption of MgAC as well as Brunauer-Emmett-Teller (BET) surface area.
关键词： Catalysis,Water/Waste Water Treatment,Fe3O4,Photo-Fenton,Aminoclay,Nanocomposite
更新于2025-09-09 09:28:46
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Ferroelectric Polarization Promoted Bulk Charge Separation for Highly Efficient CO2 Photoreduction of SrBi4Ti4O15
摘要： Fast recombination of photogenerated charge carriers in bulk remains the major obstacle for photocatalysis nowadays. Developing ferroelectrics directly as photoactive semiconducting catalysts may be promising in view of the strong ferroelectric polarization that induces the anisotropic charge separation. Here, we report a ferroelectric layered perovskite SrBi4Ti4O15 as a robust photocatalyst for efficient CO2 reduction. In the absence of co-catalysts and sacrificial agents, the annealed SrBi4Ti4O15 nanosheets with the strongest ferroelectricity cast a prominent photocatalytic CO2 reduction activity for CH4 evolution with a rate of 19.8 μmol·h-1·g-1 in the gas-solid reaction system, achieving an apparent quantum yield (AQY) of 1.33% at 365 nm, outperforming most of the reported photocatalysts. The ferroelectric hysteresis loop, piezoresponse force microscopy (PFM) and ns-level time-resolved fluorescence spectra uncover that the outstanding CO2 photoreduction activity of SrBi4Ti4O15 mainly stems from the strong ferroelectric spontaneous polarization along [100] direction, which allows efficient bulk charge separation along opposite direction. DFT calculations also disclose that both electrons and holes show the smallest effective masses along a axis, verifying the high mobility of charge carriers facilitated by ferroelectric polarization. This study suggests that the traditionally semiconducting ferroelectric materials that have long been studied as ferro/piezoelectric ceramics now may be powerfully applied in the photocatalytic field to deal with the growing energy crisis.
关键词： CO2 photoreduction,ferroelectric perovskite,spontaneous polarization,SrBi4Ti4O15 nanosheets,piezoelectric-catalysis
更新于2025-09-09 09:28:46
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Photosubstitution reactions in ruthenium(II) trisdiimine complexes: implications for photoredox catalysis
摘要： Ruthenium(II) trisdiimine complexes, including polypyridine complexes, have found many applications in the past decade as photoredox catalysts for organic transformations. This review article highlights the ability of these types of complexes to undergo photo-induced ligand exchange reactions, especially by anions. This property has been well known for decades but is generally overlooked when exploring reaction conditions for photoredox reactions. The demonstrated ability of common ruthenium(II) complexes to undergo ligand exchange reactions is surveyed, the accepted means of predicting this stability is discussed, as well as future directions.
关键词： ruthenium,photosubstitution,photoredox,photoanation,catalysis
更新于2025-09-09 09:28:46
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Ultrafast Epoxy–Amine Photopolyaddition
摘要： A new generation of light-induced production of polymeric materials is presented here. In detail, we propose to use photoacidic catalysis during the well-known epoxy?amine polyaddition reaction: it is now referred to as “epoxy?amine photopolyaddition”. Soft irradiation (405 nm visible light, 150?450 mW/cm2) of a photosensitizer/iodonium salt system leads to the production of superacids (e.g., H+, PF6?) that spectacularly enhance state-of-the-art epoxy?amine polyaddition kinetics: <3 min is necessary to obtain full conversion when >3 h is required to complete the reaction without light. Also, photoactivation greatly enhances final epoxy and amine conversions which resulted in increases (+15 °C) of the glass transition temperature of the final 3D polymer networks. This work clearly shows the extremely versatile applications for epoxy?amine photopolyaddition: thin layers (40 μm), thick layers (up to 2.5 cm), and composites (45 wt % fillers). This work paves the path toward ultrafast production of epoxy?amine composites and adhesives.
关键词： composites,photoacidic catalysis,visible light,superacids,polymer networks,epoxy?amine photopolyaddition,adhesives
更新于2025-09-09 09:28:46
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A Selective Approach for the Synthesis of Functional Oligosiloles
摘要： Synthesis of Quinoidal Fused Oligosiloles by Rhodium-Catalyzed Stitching Reaction and Theoretical Investigation of Their Properties
关键词： rhodium catalysis,oligomers,conjugation
更新于2025-09-09 09:28:46
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Photocatalytic and Antibacterial Activities of Silver and Iron Doped Titania Nanoparticles in Solution and Polyaspartic Coatings
摘要： Visible region active photocatalytic coatings are of interest for antimicrobial activity in low light applications or those employing LED lights with limited UV content. This work examined Ag and Fe doped titania nanoparticles (nTiO2) with varying dopant ranges in polyaspartic polymer coatings for potential light and dark activity. First, the Ag and Fe doped nTiO2 were synthesized by sol-gel chemistry with varying dopant concentrations, then characterized with respect to their size and aggregate size distribution, crystallinity, and surface and band gap features. The photocatalytic activity was then tested with methylene blue (MB) under both AM1.5G and visible light. From both sample sets (Ag and Fe doped nTiO2), the best photo catalytically active sample materials were chosen for antibacterial tests with gram negative Escherichia coli (E. coli) and gram positive Bacillus subtilis (B. subtilis) in (a) solution and (b) polyaspartic nanocomposites under UV and visible irradiation. The results showed that Ag doped nTiO2 samples delivered the best photocatalytic activity and excellent antibacterial action, even in the dark, attributed to both an enhanced band gap and surface area, as well as a combination of photocatalytic activity and Ag being present at the nanoparticle’s (NP) surface. No leaching of Ag at room temperature was observed from the nTiO2 structure, giving potential for next generation coatings that are both light and dark active.
关键词： Fe doping,polyaspartic composites,antibacterial activity,photo-catalysis,Ag doping,nanoparticles,Titania
更新于2025-09-09 09:28:46