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Effect of conduction band potential on cocatalyst-free plasmonic H <sub/>2</sub> evolution over Au loaded on Sr <sup>2+</sup> -doped CeO <sub/>2</sub>
摘要： There is little information on the effect of the conduction band (CB) position on plasmonic hydrogen (H2) formation under visible light irradiation over gold (Au) nanoparticles supported on semiconductors because there were no appropriate materials for which the CB position gradually changes. In this study, we analyzed the flatband potential of strontium ion (Sr2+)-doped cerium(IV) oxide (CeO2:Sr) and found that the CB position gradually shifted negatively from +0.031 V to ?1.49 V vs. NHE with an increase in the Sr2+ mole fraction. Plasmonic photocatalysts consisting of Au nanoparticles, CeO2:Sr and a platinum (Pt) cocatalyst were prepared and characterized by using X-ray diffraction, UV-vis spectroscopy, and transmission electron spectroscopy. Photocatalytic reaction under visible light irradiation revealed that H2 was produced over Au nanoparticles supported on CeO2:Sr having the CB potential of ?0.61 V vs. NHE and that the negative limit of the CB position for electron injection from Au nanoparticles existed between ?0.61 V and ?1.49 V vs. NHE. We found that Au/CeO2:Sr plasmonic photocatalysts also produced H2 without the aid of a Pt cocatalyst due to the sufficiently negative potential of electrons injected into the CB of CeO2:Sr.
关键词： hydrogen evolution,visible light irradiation,gold nanoparticles,plasmonic photocatalysts,strontium-doped cerium oxide
更新于2025-11-19 16:51:07
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Interesting makeover of strontium hexaferrites for environment remediation from excellent photocatalysts to outstanding adsorbents via inclusion of Mn3+ into the lattice
摘要： Manganese incorporated strontium hexaferrites with composition SrMnxFe12-xO19 (x= 0.0, 0.4, 0.8, 1.2, 1.6, 2.0, 3.0, 4.0 and 5.0) were fabricated via chemical co-precipitation methodology. Various characterization techniques were employed to investigate the physical properties of the synthesized hexaferrites. Powder X-Ray Diffraction (XRD) patterns revealed the formation of hexagonal phase with P63/mmc space group. FE-SEM micrographs exhibited hexagonal morphology of the synthesized materials; particle size of 125-150 nm range was observed. EDX spectra unveiled the presence of desired elements. The lattice interplanar fringe width from HR-TEM images was observed to be 0.22 nm, 0.26 nm and 0.27 nm indexed to (114), (107) and (203) planes of the manganese doped strontium hexaferrite. Surface area of the synthesized hexaferrites was found to be in the range of ~7.8 to ~8.4 m2/g, scrutinized by Brunauer–Emmet–Teller (BET) plots. Saturation magnetisation values were found to decrease with increase in Mn content from 38.7 to 11.7 emu/g, albeit retaining sufficient magnetic strength to be recovered using an external magnet. Absorption edge for all the hexaferrites was found to lie in the visible region of the spectrum. The oxidation state of different elements present in synthesized hexaferrites was scrutinized using X- ray Photoelectron Spectroscopy (XPS). To explore the catalytic efficiency of the synthesized hexaferrites, photo-fenton degradation of methyl orange (MO), remazol deep red (RDR) and p-nitrophenol (PNP) was employed. All the synthesized hexaferrites were found to be highly proficient, degrading the pollutants upto ~98%. Interestingly, astonishing adsorption of ~92.7 % was showcased by SrMn5Fe7O19, prior to the addition of oxidizing agent indicating the symptomatic transformation from excellent photocatalyst to outstanding adsorbents via incorporation of Mn3+ into the lattice. The maximum adsorption capacity of 56.20 and 112.35 mg/g was observed for MO and RDR, respectively.
关键词： photo-fenton degradation,strontium hexaferrites,adsorption,chemical co-precipitation method,manganese substituted ferrites
更新于2025-11-14 17:03:37
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A comparison of water photo-oxidation and photo-reduction using photoelectrodes surface-modified by deposition of co-catalysts: Insights from photo-electrochemical impedance spectroscopy
摘要： The purpose of this research paper is to highlight the similarities in the kinetic treatment between water photo-oxidation into molecular oxygen and water photo-reduction into molecular hydrogen, using photoelectrodes surface modified by deposition of co-catalysts. Photo-anodes made of TiO2 nanorods surface-covered by crystals of cobalt Zeolitic Imidazolate Framework (ZIF-67), and photo-cathodes made of Rh:SrTiO3 particles surface-modified by adsorption of molecules of trisdioximate hexa-chlorine cobalt (II) clathrochelate (Co(Cl2Gm)3(BCH3)2), have been prepared and used for water photo-oxidation and photo-reduction experiments, respectively. Both photoelectrodes have been characterized by SEM and cyclic voltammetry under illumination conditions. Charge transfer mechanisms have been investigated by photo-electrochemical impedance spectroscopy (PEIS). It is shown that for both systems, the presence of a co-catalyst increases the charge transfer kinetics, and that the trapping resistance is larger than the charge transfer resistance, at any operating potential.
关键词： Water photo-oxidation,Titanium dioxide nanorods,Strontium titanate,Water photo-reduction,ZIF-67 MOF
更新于2025-09-23 15:23:52
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Surface functionalization of titanium with zinc/strontium-doped titanium dioxide microporous coating via microarc oxidation
摘要： Deficient osseointegration and implant-related infections are pivotal issues for the long-term clinical success of titanium (Ti) implants. Zinc (Zn) and strontium (Sr) serve dual functions by promoting osteogenesis and inhibiting bone destruction, and Zn has good antibacterial activity. As such, this study examined the preparation of a Zn/Sr-doped titanium dioxide microporous coating (MT-Zn/Sr) on a Ti surface using microarc oxidation (MAO), with Zn and Sr evenly distributed throughout the coating. In vitro, the coating could promote the adhesion, proliferation, differentiation and mineralization of osteoblasts, showing good biological activity. Antibacterial testing demonstrated the good antibacterial activity of the coating, as it inhibited the proliferation of Staphylococcus. In vivo, MT-Zn/Sr promoted early osseointegration between the Ti substrate and the bone tissue. This work is expected to provide a new method for improving the biological activity of Ti implants and thus has important theoretical significance and great clinical prospects.
关键词： Osseointegration,Strontium,Zinc,Titanium coating,Antibacterial property
更新于2025-09-23 15:23:52
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Surface and bulk crystallization of Ba1-xSrxZn2Si2O7 from glasses in the system BaO/SrO/ZnO/SiO2 doped with Nb2O5 or Ta2O5
摘要： Stoichiometric 0.5 BaO·0.5 SrO·2 ZnO·2 SiO2 glass was doped with 5 mol% Nb2O5 or Ta2O5. The effect of these additives on the crystallization behavior was studied using thermal analyses, X-ray diffraction, as well as scanning electron microscopy including elemental analyses. The addition of Nb2O5 or Ta2O5 significantly increases the glass stability enabling the preparation of crystal-free BaO·SrO·ZnO·SiO2 glasses with almost stoichiometric composition. Besides the desired main crystal phase Ba1-xSrxZn2Si2O7, also alkaline earth tantalates and niobates as well as Zn2SiO4 are observed. The Nb-containing glass shows solely surface crystallization, whereas in the Ta-containing glass, additionally numerous Ba0.44TaO2.94 crystals precipitate in the bulk acting as seeds for the nucleation of Ba1-xSrxZn2Si2O7. If the surface crystallized layer of Ba1-xSrxZn2Si2O7 approaches such a Ba0.44TaO2.94 crystal or gets close to it, then the crystallization of Ba1-xSrxZn2Si2O7 is initiated. It is supposed that these nucleation processes are notably facilitated by the stresses present in these glass-ceramics.
关键词： barium strontium zinc silicate,heterogeneous nucleation,Glass crystallization
更新于2025-09-23 15:23:52
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Thin Films of Barium Strontium Titanate from the Viewpoint of Light-Based Applications
摘要： In this paper we report results from optical transmittance spectroscopy complemented with data on structure from XRD measurements to determine optical properties of a series of as-deposited and annealed (at 900 °C) BaSrTiO3 (BST) thin films deposited by RF magnetron sputtering. The members of the series differ by the substrate temperature and additional oxygen to accompany argon in the deposition chamber. The perovskite structure with weak preferred (110) orientation was detected for annealed BST thin films whilst the as-deposited films were amorphous. Dispersive optical properties – refractive indices, absorption coefficients and optical band gaps were determined from transmittance spectra. After annealing refractive indices increase to prove the densification of material accompanied by the thickness shrinkage. Optical band gaps calculated either by Tauc procedure or determined as iso-absorption levels are also found to be deposition dependent.
关键词： absorption coefficient,thin films,barium strontium titanate,refractive index,optical band gap
更新于2025-09-23 15:23:52
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Electrode Dependence of Local Electrical Properties of Chemical-Solution-Deposition-Derived BiFeO <sub/>3</sub> Thin Films
摘要： The nanoscale electrical properties of chemical solution deposition(CSD)-derived BiFeO3 grown on pulsed laser ablated La0.67Sr0.33MnO3//SrTiO3 (001) thin film heterostructures are investigated using a host of scanning probe microscopy techniques, including electrostatic force microscopy(EFM), scanning Kelvin probe microscopy(SKPM), piezoresponse force microscopy (PFM), and conductive AFM(CAFM). EFM and SKPM confirm the p-type nature of the CSD derived BFO thin films as well as charge accumulation at the film surface after electrical bias. For BiFeO3 films of a fixed thickness (~35 nm), the local current-voltage (I-V) behavior obtained by CAFM is strongly dependent on the La0.67Sr0.33MnO3 bottom electrode thickness. BiFeO3 films on a 20 nm thick La0.67Sr0.33MnO3 demonstrate the typical switchable diode behavior governed by polarization orientation. However, when the thickness of La0.67Sr0.33MnO3 is reduced to less than 5 nm, the BiFeO3 films show only forward diode behaviors regardless of polarization orientation, when the applied bias is up to ±4 V. Higher sweep bias (i.e. ±8V) breaks down the diode, following which the BiFeO3 film shows strong resistive switching. The interface band structure for the ultra-thin LSMO case, which is very sensitive to accumulation/depletion of carriers at the BFO-LSMO interface, is suggested as the trigger for this resistive switching.
关键词： chemical solution deposition,ferroelectric,electrical properties,ultrathin lanthanum strontium manganite,p-type bismuth ferrite thin films
更新于2025-09-23 15:23:52
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AIP Conference Proceedings [Author(s) 1ST INTERNATIONAL CONGRESS ON SOLAR ENERGY RESEARCH, TECHNOLOGY AND APPLICATIONS (ICSERTA 2018) - Ouarzazate, Morocco (8–10 May 2018)] - Synthesis and MID-IR characterization of strontium hexaferrite nanoparticles using gel to crystallization technique
摘要： Synthesis and MID-IR characterization of strontium hexaferrite nanoparticles using gel to crystallization technique. Strontium hexaferrite (SrFe12O19) nanoparticles have been synthesized using gel to crystallization technique. Citric acid, iron nitrate and strontium nitrate were used as starting materials to prepare the gel. The prepared gel was heated at 100°C for 4 hrs in muffle furnace and sample was annealed at 800°C for 4 hrs. The prepared sample was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The XRD pattern confirms the formation of single phase SrFe12O19 nanoparticles. The FTIR spectrum shows the absorption bands in the range 400-600 cm-1 which are assigned to metal-oxygen vibrations. The prepared nanoparticles show the formation of single phase and can be used for various applications such as magnetic recording media, microwave devices and permanent magnets.
关键词： XRD,FTIR,gel to crystallization,Strontium hexaferrite,nanoparticles
更新于2025-09-23 15:23:52
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Single-Molecule Based Electroluminescent Device as Future White Light Source
摘要： During last two decades spectacular development of light emitting diodes (LEDs) has been achieved owing to their widespread application possibilities. However, traditional LEDs suffer from unavoidable energy loss due to the down conversion of photons, toxicity due to the involvement of rare-earth materials in their production, higher manufacturing cost, and reduced thermal stability that prevent them from all-inclusive applications. To address the existing challenges associated with current commercially available white LEDs, herein, we report on a broadband emission originating from an intrinsic lanthanide-free single-molecule based LED. Self-assembly of a butterfly-shaped strontium-based compound {[Sr(H2btc)2(MeOH)(H2O)2]·2H2O} (1) was achieved through the reaction of Sr(NO3)2 with a benzene-1,2,3-tricarboxylic acid hydrate (1,2,3-H3btc) under hydrothermal conditions. White LED based on this single molecule exhibited a remarkable broadband luminescent spectrum with Commission Internationale de l’Eclairage (CIE) coordinates at (0.33, 0.32) under 30 mA current injection. Such a broad luminescent spectrum can be attributed to the simultaneous existence of several emission lines originating from the intramolecular interactions within the structure. To further examine the nature of the observed transitions, density functional theory (DFT) calculations were carried out to explore the geometric and electronic properties of the complex. Our study thus paves the way toward a key step for developing a basic understanding and the development of high performance broadband light emitting devices with environment-friendly characteristics based on organic?inorganic supramolecular materials.
关键词： Electroluminescence,Photoluminescence,Single Molecule,WLEDs,Strontium
更新于2025-09-23 15:23:52
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Study of the fabrication and organization properties of copper-based Ba<inf>1?x</inf>Sr<inf>x</inf>TiO<inf>3</inf> composites
摘要： Barium strontium titanate ceramic particles which have negative thermal expansion properties when it reaches reinforcement and copper which have high thermal conductivity are choosen as matrix of composites. Different content of strontium in barium strontium titanate ceramic particles reinforced copper matrix composites are prepared by Spark Plasma Sintering for electronic packaging applications. The methods of microstructure analysis are employed to observe the morphology of reinforcement and matrix in composites, and interfacial characteristics. Thermal expansion instrument and thermal conductivity equipment are used to test and analyze the thermal expansion and thermal conductive ability of the composites. And the conductivity of the composites is tested by intelligent resistance tester.
关键词： Thermal expansion ability,Barium strontium titanate,Copper matrix composites
更新于2025-09-23 15:22:29