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A sola??gel synthesis to prepare size and shape-controlled mesoporous nanostructures of binary (IIa??VI) metal oxides
摘要： A base-catalyzed sol–gel approach combined with a solvent-driven self-assembly process at low temperature is augmented to make manganese oxide (Mn3O4), copper oxide (CuO), and magnesium hydroxide (Mg(OH)2) nanostructures with size- and shape-controlled morphologies. Nanostructures of Mn3O4 with either hexagonal, irregular particle, or ribbon shape morphologies with an average diameter ranged from 100 to 200 nm have been prepared in four di?erent solvent types. In all morphologies of Mn3O4, the experimental XRD patterns have indexed the nanocrystal unit cell structure to triclinic. The hexagonal nanoparticles of Mn3O4 exhibit high mesoporocity with a BET surface area of 91.68 m2 g?1 and BJH desorption average pore diameter of ～28 nm. In the preparation of CuO nanostructures, highly nanoporous thin sheets have been produced in water and water/toluene solvent systems. The simulated XRD pattern matches the experimental XRD patterns of CuO nanostructures and indexes the nanocrystal unit cell structure to monoclinic. With the smallest desorption total pore volume of 0.09 cm3 g?1, CuO nanosheets have yielded the lowest BET surface area of 18.31 m2 g?1 and a BHJ desorption average pore diameter of ～16 nm. The sol of magnesium hydroxide nanocrystals produces highly nanoporous hexagonal nanoplates in water and water/toluene solvent systems. The wide angle powder XRD patterns show well-de?ned Bragg's peaks, indexing to a hexagonal unit cell structure. The hexagonal plates show a signi?cantly high BET surface area (72.31 m2 g?1), which is slightly lower than the surface area of Mn3O4 hexagonal nanoparticles. The non-template driven sol–gel synthesis process demonstrated herein provides a facile method to prepare highly mesoporous and nanoporous nanostructures of binary (II–VI) metal oxides and their hydroxide derivatives, enabling potential nanostructure platforms with high activities and selectivities for catalysis applications.
关键词： catalysis applications,size and shape-controlled morphologies,mesoporous nanostructures,binary (II–VI) metal oxides,sol–gel synthesis
更新于2025-09-23 15:19:57
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Study on the controlled synthesis of Zr/TiO2/SBA-15 nanophotocatalyst and its photocatalytic performance for industrial dye reactive red Xa??3B
摘要： Nanophotocatalytic technology is one of the most promising technologies to treat industrial dyes in waste water. Nanosized TiO2 was loaded on mesoporous SBA-15 molecular sieve by chemical method to prepare TiO2/SBA-15 (TS1) in this work. Then, the transition metal element Zr was further deposited on the surface of TS1 to obtain Zr/TiO2/SBA-15 (ZTS) nanophotocatalysts. The crystal structure, morphology, element distribution and pore size distribution of several samples were studied using small-angle x-ray scattering, X-ray diffraction, Transmission electron microscope, Scanning electron microscope, X-ray photoelectron spectroscopy, N2 adsorption-desorption, UV–Vis diffuse reflectance spectroscopy. The photocatalytic performance of the nanophotocatalyst was evaluated by photocatalyzing reactive red X–3B. The results show that the ZTS nanophotocatalyst has a good mesoporous structure, wherein, the TiO2 is an anatase phase. The specific surface of ZTS reaches 538.24 m2/g and its spectral absorption threshold reaches 425 nm. When the deposition amount of Zr is moderate the ZTS nanophotocatalyst shows quite high photocatalytic activity. In pH 2–10, the photocatalytic activity of ZTS exhibits change with variation of pH value. Under proper conditions, the degradation rate of reactive red X–3B reaches about 96% in ZTS photocatalytic system. Therefore, ZTS nanophotocatalyst has great potential in the treatment of dye wastewater.
关键词： Nanophotocatalyst,Reactive red X–3B,Mesoporous material,Zr,TiO2
更新于2025-09-23 15:19:57
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Enhanced photocatalytic activity of a mesoporous TiO2 aerogel decorated onto three-dimensional carbon foam
摘要： TiO2/carbon composites have been well studied as solar-light photocatalysts because they combine the advantages of TiO2 (good photocatalytic activity) and carbon (enhanced charge carrier separation). Mesoporous TiO2 aerogels are fragile by nature and the addition of free-standing three-dimensional (3D) porous carbon foam (CF) not only makes it easy for separation and collection after photocatalytic treatment but also acts as a scaffold for the long-term application of TiO2 aerogels in the photocatalysis. Hence, recent reports have shown that mesoporous TiO2 aerogel/CF composites synthesized by the carbonization of a polymer followed by using the sol-gel method are significant for use in photocatalysis applications. In addition, the 3D macroporous CF not only acts as a support for TiO2 aerogels but also improves the efficiency of light use and extends the photoresponse of TiO2 to the visible region. The TiO2 aerogel was homogeneously distributed onto the 3D CF because of the vacuum infiltration used during the synthesis of the composites. The simulated solar-light irradiated photocatalytic degradation of Rhodamine B organic pollutant was used to evaluate the TiO2 aerogel/CF composite catalysts, which was higher than with a pristine TiO2 aerogel. This facile synthesis approach for 3D foam type TiO2/carbon composites could be useful in the treatment of wastewater.
关键词： anatase,Mesoporous TiO2 aerogel,photocatalysis,sol-gel method,carbon foam
更新于2025-09-23 15:19:57
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Photo-electrochemical Behavior of Silver Nanoparticles inside Mesoporous Titania: Plasmon induced charge separation effect
摘要： The self-assembly block copolymer method was used to synthesize mesoporous titania films and silver nanoparticles (NPs) were grown inside the films. Such silver NPs-titania films are known for their multicolor photochromic properties, due to a photo-oxidation reaction of silver in the presence of titania under light excitation which is attributed to a plasmon induced charge separation (PICS). Here, the photo-electrochemical properties of these composite films have been investigated at different light wavelengths and chemical environment in order to characterize the light-induced redox reactivity modifications. Cyclic voltammetry (CV) study shows that the Ag+ electro-reduction peak potential varies depending on the light irradiation, which determines the state of the silver nanoparticles complexed or not by titania.
关键词： cyclic voltammetry,Silver nanoparticles,photochromism,plasmon,mesoporous titania
更新于2025-09-19 17:15:36
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Bi <sub/>2</sub> SiO <sub/>5</sub> @g-SiO <sub/>2</sub> upconverting nanoparticles: a bismuth-driven core–shell self-assembly mechanism
摘要： Core–shell systems have attracted increasing interest among the research community in recent years due to their unique properties and structural features, and the development of new synthetic strategies is still a challenge. In this work, we have investigated lanthanide-doped Bi2SiO5 nanocrystal formation inside mesoporous silica nanoparticles (MSNs). The role of both synthesis temperature and concentration of the bismuth precursor impregnated into the MSNs is discussed, showing an unprecedented strategy for the simultaneous stabilization of a crystalline core and a glassy shell. Temperature dependent synchrotron radiation X-ray powder diffraction (SR-XRPD) and high resolution transmission electron microscopy (HR-TEM) analyses allow one to follow the crystalline core growth. A mechanism for the formation of a Bi2SiO5@g-SiO2 core–shell nanosystem is proposed. In addition, the easy tunability of the color output of the upconverting system is demonstrated by means of suitable doping lanthanide ions with potential applications in several fields.
关键词： upconversion luminescence,mesoporous silica,core–shell nanoparticles,bismuth silicate,Bi2SiO5
更新于2025-09-19 17:15:36
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Heterostructures of mesoporous TiO2 and SnO2 nanocatalyst for improved electrochemical oxidation ability of Vitamin B6 in pharmaceutical tablets
摘要： The detection of water soluble vitamins using electrochemical method is widely established in pharmaceutical quality control laboratories, and especially the recent advances in hybrid heterostructure nanomaterials has devoted to enhance the significant analytical parameters like sensitivity, selectivity and fast response time. Herein, we report the synthesis of a hybrid heterostructure comprising SnO2 nanoparticles supported mesoporous TiO2, and the obtained nanocomposite were fabricated over glassy carbon electrode (GCE) for the electrochemical oxidation of vitamin B6 in pharmaceutical tablets. The designed SnO2-TiO2/GC modified electrode exhibits well-defined oxidation peak with lowering over-potential and larger signal response compared to the pristine counterparts, and it is mainly due to the formation of abundant active surface layer offered by SnO2 cocatalyst, and thus significantly enhances the electrochemical surface area. Differential pulse voltammetry (DPV) measurements revealed a sharp increase in the anodic peak current upon addition of increasing concentration of vitamin B6. The analytical performance of the modified electrode displayed a wide linear range (0.1 - 31.4 μM), high selectivity, and excellent sensitivity (759.73 μA mM-1 cm-2) with low detection limit (35 nM). Thus, the resultant mesoporous hybrid nanocatalyst provides an efficient electrochemical platform for determination of various potential analytes.
关键词： electrochemical sensor,Tin oxide (SnO2) cocatalyst,mesoporous,Titanium dioxide (TiO2),Vitamin B6
更新于2025-09-19 17:15:36
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Facile fabrication of well-polarized Bi <sub/>2</sub> WO <sub/>6</sub> nanosheets with enhanced visible-light photocatalytic activity
摘要： Designing a templating strategy for directing mesopore growth along different crystallographic directions is essential for fabricating two- or three-dimensional single-crystalline mesoporous zeolites. However, so far, mesopores formed in MFI zeolites by soft templates have mostly been generated by disrupting growth along the b axis; generating mesopores by disrupting growth along the a axis is rare. Herein, a single-crystalline mesoporous MFI zeolite (SCMMZ) with sheet-like mesopores layered along the a and b axes was synthesized using a triply branched surfactant with diquaternary ammonium groups connected to 1,3,5-triphenylbenzene by a six- and eight-carbon alkyl chain (TPB-6 and 8). The sheet-like mesopores were embedded in the MFI framework and were retained even after calcination. Molecular mechanics calculations provided evidence of low binding energy configurations of the surfactant that directed the growth of straight and zigzag channels along the b and a axes, respectively. The formation of nanosheets was attributed to the geometric matching of the arrangement of the aromatic groups to the zeolite framework.
关键词： mesoporous zeolite,transmission electron microscopy,surfactants,self-assembly,MFI
更新于2025-09-19 17:15:36
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The preparation of spherical mesoporous g-C3N4 with highly improved photocatalytic performance for H2 production and rhodamine B degradation
摘要： Spherical mesoporous graphitic carbon nitride (g-C3N4) was successfully prepared through spherical mesoporous silica as sacrificial templates, and analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analyzer, N2 adsorption-desorption isotherm, BET, UV-vis diffuse reflectance spectra and photoluminescence spectra. Experimental results indicated that as-prepared g-C3N4 exhibited spherical morphology with high surface area due to the introduced porous structure, which made the as-prepared g-C3N4 possess much higher activity than the bulk g-C3N4 for producing H2 and decomposing rhodamine B (RhB) under visible light, and it also kept excellent recycling activity. Hence, this investigation provided a simple strategy for the fabrication of porous special morphology graphitic carbon nitride with excellent photocatalytic activity.
关键词： Visible light,spherical mesoporous g-C3N4,Photocatalyst,Photocatalytic activity
更新于2025-09-19 17:15:36
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Cyano-rich mesoporous carbon nitride nanospheres for visible-light-driven photocatalytic degradation of pollutants
摘要： Visible-light-responsive photocatalysis offers exciting opportunities for sustainable environmental pollution control, but the unsatisfactory photoactivity of the existing photocatalysts impedes their practical application. Here, we fabricated a high-activity mesoporous carbon nitride nanosphere (MCNS) photocatalyst by a hard template synthesis method through incomplete polycondensation of the cyanamide precursors during thermal polymerization. The MCNS showed a unique nanosphere structure with a larger specific surface area and possessed more abundant cyano groups than two other graphitic carbon nitride (g-C3N4) materials (i.e., nanosheet and bulk g-C3N4). Experimental results and theoretical calculations indicate important roles of the cyano groups in narrowing the catalyst band gap to favor visible light absorption and accelerating the separation of the electron–hole pairs. With such superior surface properties and improved charge separation efficiency, the MCNS exhibited 14.7 times higher photocatalytic activity for bisphenol A (BPA) degradation than the bulk g-C3N4. The MCNS also showed good stability during repeated use. Therefore, the as-prepared MCNS has great potential for visible-light-responsive photocatalysis in environmental remediation and other photocatalytic applications.
关键词： pollutant degradation,visible-light-driven photocatalysis,bisphenol A,environmental remediation,Cyano-rich mesoporous carbon nitride nanospheres
更新于2025-09-19 17:15:36
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Synthesis of surface-replicated ultra-thin silica hollow nanofibers using structurally different carbon nanofibers as templates
摘要： Ultra-thin silica hollow nano?bers were successfully synthesized using three kinds of well-de?ned carbon nano?bers (CNFs) with di?erent surface structures as e?ective templates via pyrolysis of polycarbomethylsilane-coated CNFs. The prepared silica hollow nano?bers replicated the characteristic surface morphologies of the CNFs, such as herringbone, platelet, and tubular types with edge or basal planes. Especially, the unique HCNF template, with tiny ?bril aggregates on the surface, was the most e?ective template material for synthesizing ultra-thin silica hollow nano?bers with uniform and hierarchical meso-pores and high surface areas (over than 680 m2/g). The chemical and physical properties of the silica nano?bers were evaluated with various analytical techniques, such as TGA, HR-TEM, FE-SEM, XRD, XPS, and N2 adsorption/desorption, and discussed in detail.
关键词： Carbon nano?ber,Template synthesis,Mesoporous ultra-thin silica hollow nano?ber
更新于2025-09-19 17:15:36