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Four Co( <scp>ii</scp> ) coordination polymers based on 4,4′-(1 <i>H</i> -1,2,4-triazol-1-yl)methylenebis(benzoic acid): syntheses, structural diversity, magnetic properties, dye adsorption and photocatalytic properties
摘要： Four Co(II) coordination polymers based on 4,4′-(1H-1,2,4-triazol-1-yl)methylenebis(benzoic acid) (H2tmlb), namely: {[Co4(tmlb)4(H2O)]·2CH3CN·4H2O}n (1), {[Co(tmlb)(bbibp)]·1.5CH3OH·2H2O}n (2), {[Co2(tmlb)2(bimmb)]·6CH3CH2OH·4H2O}n (3), and {[Co(tmlb)(bibp)(H2O)]·DMA}n (4) (bbibp = 4,4′-bis(benzoimidazo-1-yl)biphenyl, bimmb = 1,4-bis(imidazol-1-ylmethyl)benzene, bibp = 4,4′-bis(imidazolyl)biphenyl), have been synthesized under solvothermal conditions. Four Co complexes have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). The single-crystal X-ray diffraction analysis reveals that complex 1 shows a two-fold interpenetrating (3,6,6)-connected framework with a Schl?fli symbol of (4·62)2(42·610·83) topology; complex 2 shows a two-fold interpenetrating uninodal 4-connected cds topology with a point symbol of (65·8); complex 3 shows a 2D → 3D supramolecular structure through weak interactions; complex 4 shows a (3,4,6)-connected network with a point symbol of (4·62)2(42·64·93·106)(64·9·10) topology. Furthermore, the variable temperature magnetic susceptibilities of complexes 1–4 have been discussed. Complex 4 can selectively adsorb sulfate-containing dyes by Lewis acid–base interactions. And the four complexes all exhibit excellent photocatalytic capability in degradation of MB/MV.
关键词： Structural diversity,Coordination polymers,Photocatalytic properties,Metal–organic frameworks,Dye adsorption,Magnetic properties
更新于2025-09-19 17:15:36
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Synthesis, characterization and photocatalytic properties of nanoscale pyrochlore type Bi2Zr2O7
摘要： Developing e?cient visible-light-driven photocatalysts for environmental decontamination is of considerable importance in solar energy conversion and utilization. Herein, nanoscale Bi2Zr2O7 pyrochlore structure materials was synthesized by a facile coprecipitation method and the in?uence of nano-size e?ects on its photocatalytic reduction of Cr(VI) under visible light was investigated. Results show that the resultant Bi2Zr2O7 prepared at 2 h optimum calcination time with uniform small crystal size leading to a high speci?c surface area exhibits the best photocatalytic performance. In addition, the possible mechanisms of the photocatalytic reduction of Cr(VI) over Bi2Zr2O7 were proposed.
关键词： Bi2Zr2O7,Photocatalytic properties,Coprecipitation method,Cr(VI) reduction
更新于2025-09-19 17:15:36
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Impact of the Plasmonic Metal Oxide-Induced Photocatalytic Processes on the Interaction of Quantum Dots with Metallic Nanoparticles
摘要： We study plasmonic control of photocatalytic properties of metal oxides and the ways they influence interaction of quantum dots with metallic nanostructures. For this, gold nanostructures are coated with ultrathin layers of metal oxides (Al, Cu, Cr, or Ti oxide) and then covered with CdSe/ZnS quantum dots. The results show how the photocatalytic properties of such metal oxides are renormalized by plasmon near fields. In the cases of Al, Cr, and Ti oxides, the results mostly indicate the direct impact of plasmon fields via enhancement of optical excitations of the quantum dots. For the case of Cu oxide, however, the outcomes are found to be quite unique. In the absence of the plasmonic structures, such an oxide (CuO) presents highly active photocatalytic processes, leading to complete annihilation of the quantum dot emission. In the presence of the metallic nanostructures, the emission of such quantum dots is revived, offering an ultrafast decay process (～112 ps). These results indicate that in the case of CuO, the plasmonic metal oxide-induced photocatalytic processes include not only direct impact of plasmon near fields on the optical excitations of quantum dots but also the enhancement of interband transitions in CuO nanoparticles. The effects of energy transfer from quantum dots to metallic nanostructures and its equalization with Purcell effects on such processes are discussed.
关键词： ultrafast decay process,photocatalytic properties,plasmonic control,metallic nanostructures,Purcell effects,plasmon near fields,energy transfer,quantum dots,metal oxides
更新于2025-09-19 17:13:59
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Electrodeposition and Photocatalytic Performance of Self-Assembled Tulip Flower/Mulberry-Like CuO Nanostructures
摘要： Copper oxide as a p-type semiconductor has been widely used in the field of catalysis. Monoclinic CuO nanostructures with various shapes have been synthesized on indium tin oxide-coated glass substrates via electrodeposition with annealing at 400°C for 2 h, and the influence of different electrodeposition parameters on their properties investigated. X-ray diffraction analysis and scanning electron microscopy were used to characterize the phase structure and surface morphology, respectively, of the synthesized CuO films, and ultraviolet–visible spectrophotometry was used to study their optical absorption. Moreover, we measured their photocatalytic properties using photodegradation tests under light irradiation with methylene blue as a simulated organic pollutant. The results showed that the light absorbance of the CuO nanostructure was improved in the visible region. The photodegradation rate for methylene blue reached 93% in 210 min. The prepared nanomaterials are promising for use as good photocatalysis in the field of environmental treatment.
关键词： CuO films,photocatalytic properties,Electrodeposition,growth mechanism
更新于2025-09-11 14:15:04
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Ag-Ag2S quantum-dots modified TiO2 nanorod arrays with enhanced photoelectrochemical and photocatalytic properties
摘要： In this paper, highly ordered titanium dioxide nanorod (TNR) arrays decorated with Ag-Ag2S quantum-dots (QDs) were synthesized on FTO substrate through hydrothermal treatment and in-situ vulcanization. The content of Ag2S QDs on Ag/TNR was controlled by changing the immersion time of Ag/TNR in the N-N-dimethyl formamide (DMF) solution containing dissolved sulfur element. The morphology, structure, composition and optical, photoelectric and photocatalytic properties of QDs/TNR arrays were studied in detail. In the visible range, the QDs/TNR array with a soaking time of 12 h exhibits the maximal photocurrent density (0.082 mA/cm2) and photodegradation rate (62.2%), which is 5.5 and 1.85 times higher than that of pure TNR. The improvement of these properties could be attributed to synergy effect between Ag and Ag2S materials. That is, Ag QDs can stably capture and transmit photo-generated electrons from the TNR surface, whereas the Ag2S promoter is regarded as the interface active sites to enhance photocatalytic reactions. Therefore, the synergistic effect of Ag-Ag2S can significantly enhance the photoelectrochemical and photocatalytic propertise of the TNR arrays.
关键词： Ag-Ag2S quantum-dots,photoelectrochemical and photocatalytic properties,synergistic effect,TiO2 nanorod arrays
更新于2025-09-10 09:29:36
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2-D Silver-thiocyanate Layers Directed by Viologens: Structural Transformations upon Low Pressure Stimuli, Piezochromic Luminescence, Photocurrent Responses and Photocatalytic Properties
摘要： The reactions of AgSCN with excess KSCN in presence of linear viologens templates afford seven new hybrids, {(MV)[Ag4(SCN)6]}n (1), {(MV)[Ag2(SCN)4]}n (2), {(EV)[Ag4(SCN)6]}n (3), {(EV)[Ag2(SCN)4]}n (4), {(BV)[Ag4(SCN)6]}n (5), {(CMV)[Ag2(SCN)4]}n (6) and {(BMPE)[Ag2(SCN)4]}n (7), (MV2+=methyl viologen, EV2+=ethyl viologen, BV2+=benzyl viologen, CMV2+=cyanomethyl viologen, BMPE2+=1,2-bis(N-methylpyridiniim-4-yl)ethane). The silver-thiocyanate skeletons with formula of [Ag4(SCN)6]n 2n- and [Ag2(SCN)4]n 2n- are the scarce representative examples of the 2-D polypseudorotaxane arrays penetrated (for 1-6) or intercalated (for 7) by viologen dications. Upon the external low pressure stimulus, the 2-D silver-thiocyanate layers penetrated by cations exhibit loser packing with longer Ag-S(N) bond lengths, weaker CT interactions and larger cavities, but the contrary trend can be found on compound with intercalated organic cations. Due to the strong CT interactions between viologens and silver-thiocyanate skeletons, the charge transfers can occur at room temperature. Interestingly, 7 represents typical reversible piezochromic luminescence behaviour. In addition, they show excellent photocurrent responses and efficient photocatalytic degeneration performances on organic dyes. Finally, their band structures and density of states before and after compression based on DFT calculations were executed to correlate their properties.
关键词： Piezochromic Luminescence,Viologens,Silver-thiocyanate,Photocurrent Responses,Photocatalytic Properties,Structural Transformations
更新于2025-09-10 09:29:36
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Functional properties of LaxCe1?xO2?δ nanocrystals and their bulk ceramics
摘要： Structure–property correlations were investigated for LaxCe1?xO2?δ (x = 0.05, 0.15) system (for both nanoparticles and ceramic). The nanoparticles were synthesized by the co-precipitation route and characterized for their structural, catalytic and visible light driven photocatalytic properties. Synthesised LaxCe1?xO2?δ nanopowders depicted phase purity with excellent compositional control as confirmed by various structural characterisation tools. The 15% La3+-doped ceria nanoparticles portrayed superior photocatalytic properties; complete degradation (99%) of the methylene blue dye was observed within 60 min of visible light irradiation under an alkaline medium. High density (> 96%) of the ceramics (sintered at 1580 °C for 2 h) confirmed promising sinterability of the synthesised powders. The ionic conductivities of the LaxCe1?xO2?δ ceramics increased with temperature and frequency owing to enhanced oxygen vacancies in the ceria matrix as a result of doping (of La3+-ions); a maximum conductivity of ~ 8.4 × 10?2 S cm?1 was obtained at 900 °C for the 15% La3+-doped ceria ceramics at 1 MHz frequency.
关键词： LaxCe1?xO2?δ,nanocrystals,photocatalytic properties,co-precipitation,ionic conductivity,bulk ceramics
更新于2025-09-10 09:29:36
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Bi <sub/>5</sub> O <sub/>7</sub> NO <sub/>3</sub> and Ag/Bi <sub/>5</sub> O <sub/>7</sub> NO <sub/>3</sub> composites: one-step solution combustion synthesis, characterization and photocatalytic properties
摘要： In the present study, Bi5O7NO3 and Ag/Bi5O7NO3 composites, as novel efficient photocatalysts, were synthesized via a one-step solution combustion synthesis (SCS) using bismuth nitrate (Bi(NO3)3·5H2O) as an oxidant, tartaric acid (C4H6O6) as a fuel, and silver nitrate (AgNO3) as an Ag source. The amount of Ag in the composite was tailored by varying the AgNO3 content during the SCS process. The orthorhombic Bi5O7NO3 crystal structure was confirmed by XRD, FT-IR and XPS. It was found by EDS and TEM that in the Ag-containing composite, Ag was uniformly distributed on the Bi5O7NO3 matrix. The Ag decoration improved the Bi5O7NO3 photocatalytic efficiency for methyl orange (MO) degradation, likely owing to the relatively low recombination rates of electrons and holes. The 5 mol% Ag/Bi5O7NO3 composite exhibited the best photocatalytic performance (95% in 60 min), which was 1.5 times higher compared to that of pure Bi5O7NO3. In addition, a mechanism of the photocatalytic MO degradation reaction was proposed, which the reactive species O2? played an important role in degrading pollutants.
关键词： Bi5O7NO3,methyl orange degradation,Ag/Bi5O7NO3 composites,solution combustion synthesis,photocatalytic properties
更新于2025-09-04 15:30:14