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Acetic anhydride as oxygen donor in the non-hydrolytic sol-gel synthesis of mesoporous TiO2 with high electrochemical lithium storage performances
摘要： An original, halide-free non-hydrolytic sol-gel route to mesoporous anatase TiO2 with hierarchical porosity and high specific surface area is reported. This route is based on the reaction at 200 °C of titanium (IV) isopropoxide with acetic anhydride, in the absence of a catalyst or of a solvent. NMR studies indicated that this method provides an efficient, truly non-hydrolytic and aprotic route to TiO2. Formation of the oxide involves acetoxylation and condensation successive reactions, both with ester elimination. The resulting TiO2 materials were nanocrystalline, even before calcination. Small (≈10 nm) anatase nanocrystals spontaneously aggregated to form mesoporous micron sized particles with high specific surface area (260 m2 g-1 before calcination). Evaluation of the lithium storage performances showed a high reversible specific capacity, particularly for the non-calcined sample with the highest specific surface area favoring pseudo-capacitive storage: 253 mAh g-1 at 0.1C and 218 mAh g-1 at 1C (C = 336 mA g-1). This sample also showed good cyclability (>92% retention after 200 cycles at 336 mA g-1) with a high coulombic efficiency (99.8 %). Synthesis in the presence of a solvent (toluene or squalane) offers the possibility to tune the morphology and texture of the TiO2 nanomaterials.
关键词： anatase,mesoporous,acetic anhydride route,non-hydrolytic sol-gel,Li-ion batteries
更新于2025-09-23 15:23:52
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Improved galvanic porous silicon fabrication using patterned electrodes
摘要： On-chip porous silicon can be fabricated in a number of ways, but perhaps the simplest is a galvanic method that requires no external power supply. While this etch process is relatively simple, the etch is highly dependent on the surface area ratio (SAR) of a backside precious metal and frontside silicon surface, which respectively act as the cathode and the anode of an electrochemical cell. The SAR controls the etch current density, and therefore local variations can create high current densities that have detrimental effects on the quality of the final porous silicon film. The present study investigates the use of patterned backside platinum electrodes with the galvanic etch technique. The use of a patterned backside electrode that mimics the silicon pattern on the frontside, provides a more consistent etch current throughout the entire sample, and thus a more uniform porous silicon film. A triangular shape porous silicon film was tested in this work for comparison to a previous study utilizing an unpatterned electrode. With patterned electrodes, an etch depth variation percentage was observed throughout the length of the film of 8%. This is a considerable improvement over a 108% depth variation observed with a similar frontside silicon pattern and an unpatterned backside electrode.
关键词： porous silicon,electrochemical etching,mesoporous,galvanic etching
更新于2025-09-23 15:23:52
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Functionalization of silicon nanowires by iron oxide and copper for degradation of phenol
摘要： Iron oxide (Fe3O4) and copper-functionalized silicon nanowires (SiNWs) from silicon powder mesh < 500 with a spherical structure have been successfully synthesized as a heterogeneous catalyst for the degradation of phenol. This synthesized catalyst was prepared by nanosilicon wire powders. SiNWs have attracted much attention due their potential application in nanoscale devices such as field effect transistors, chemical or biological sensors, battery electrodes and photovoltaics. The SiNW properties were reinforced by functionalization. The synthesis of this catalyst was done by an in situ method for the decoration of SiNWs. Magnetic metal oxide compounds have been chosen not only to accelerate the catalyst recovery but also to improve the time duration of pollution elimination. Also, Cu nanoparticles were added in order to evaluate the catalytic property. In this work, the maximum amount of phenol degradation was obtained near 99.99%. Hybrid surface morphologies were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, the Brunauer–Emmette–Teller model and high-performance liquid chromatography.
关键词： Mesoporous,Fe3O4–Cu-SiNWs catalyst,Phenol degradation,Sphere
更新于2025-09-23 15:23:52
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Significant enhancement of photoactivity in one-dimensional TiO2 nanorods modified by S-, N-, O-doped carbon nanosheets
摘要： Titanium dioxide (TiO2) represents one of the most active photocatalysts among metal oxides for the degradation of pollutants and for solar water splitting to produce hydrogen. The most critical drawbacks hindering its broad practical use are the absorption majorly in the UV part of solar spectrum and slow charge dynamics. Combination of TiO2 with a suitable partner in a hybrid nanostructure can effectively address these drawbacks. Here we report a novel nanocomposite system based on one-dimensional TiO2 nanorods wrapped with a sulfur-, nitrogen-, and oxygen-doped carbon (SNOC) nanosheets. The SNOC nanosheets are synthesized by a cost-effective and facile route using eco-friendly carrageenan as a sulfur, oxygen, and carbon source and urea as a nitrogen source. Silica was used as the templating agent that leads to large surface area materials after its removal at the end of the synthesis. Therefore, the synthesized material exhibits superior photocatalytic performance for decoloring representative Rhodamine B (RhB) under visible light irradiation. SNOC shows the apparent rate constant of 7.6 × 10–3 min–1, which is almost 3 times higher than that of a SNOC material without using silica (2.8 × 10–3 min–1). This performance of doped carbon material can be assigned to the effect of large surface area and effective visible light adsorption. The TiO2 NRs / SNOC nanocomposite was investigated for photoelectrochemical water splitting showing much higher photocurrent densities (0.85 mA cm–2) than pure TiO2 nanorod arrays (0.35 mA cm–2), which was due to significant improvement in the charge transfer dynamics and co-catalytic effect of SNOC. All the materials prepared were evaluated on the basis of physical properties such as crystalline structure, optical absorption, surface topography, and electronic properties.
关键词： Water splitting,Photoelectrochemistry,Photocatalysis,Heterojunction,TiO2 nanorods,S, N, O-doped mesoporous carbon
更新于2025-09-23 15:23:52
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Mesoporous silica-coated gold nanoframes as drug delivery system for remotely controllable chemo-photothermal combination therapy
摘要： Tumor cells experience higher chemotherapy stress under condition of elevated temperature. As a result, developing novel nanoagents that integrates chemotherapy and thermotherapy holds great promise in biomedicine. Herein, utilizing spatially confined galvanic replacement method, we fabricated a yolk-shell Au@mSiO2 nanoframes with Au NPs and mesoporous silica as yolk and shell, respectively, to sever as an excellent drug nanocarrier with effective photothermal conversion efficiency. Taking full advantage of the high temperature response of the Au@mSiO2 nanoframes, the phase change material 1-tetradecanol (TD) was creatively employed as gatekeepers, intelligently controlling the release of loaded agents. Then, the actively targeted Alanine-Alanine-Asparagine, legumain-recognizable oligopeptides was decorated on the surface of the prepared nanoframes. Upon exposure to near-infrared light, the GC-PtAu@mSiO2-TD nanoframes not only exhibited a high localized temperature response, but also triggered the quick release of loaded cargos, and thus improved the chemotherapeutic efficacy. The in vitro cytotoxicity studies indicated the remarkable synergistic effects. Meanwhile, the laser confocal studies and flow cytometry showed the oligopeptides facilitated the intracellular uptake of GC-PtAu@mSiO2-TD nanoframes in MGC-803 cells. Our study highlighted the great potential of the GC-PtAu@mSiO2-TD nanoframes in drug delivery and the combination of chemotherapy and photothermal therapy.
关键词： Cisplatin,Mesoporous silica-gold nanoframes,Phase-change materials,Photothermal therapy,Controlled release
更新于2025-09-23 15:23:52
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Photocatalytic overall water splitting on isolated semiconductor photocatalyst sites in an ordered mesoporous silica matrix: A multiscale strategy
摘要： Photocatalytic overall water splitting (OWS) in a stoichiometric ratio has attracted increasing attention for the realization of a sustainable, environmentally friendly future. However, this reaction exhibits sluggish kinetics due to efficiency limitations of the involved steps, including photon absorption, electron transfer, and the reactions that occur at triple-phase boundary regions. Herein, we report a general multiscale strategy to address this challenge by designing a model composite catalyst with a high loading density of isolated Bi0.5Y0.5VO4 nanocrystals, as building blocks, dispersed in a hexagonally ordered mesoporous silica matrix. In contrast to the well-recognized heterojunction formed between different semiconductors, we show that confined growth favours the formation of isolated quaternary solid-solution photocatalysts (Bi0.5Y0.5VO4), which can further interface with the insulating silica to overcome temperature limitations and exhibit enhanced photon absorption and electrochemical and mass transfer properties due to the transparent periodic porous structure of silica and the as-formed small nanocrystals with high crystallinity and a passivated surface. When the semiconductor photocatalyst is incorporated with the inert silica insulator, this nanoarchitecture does not inhibit the OWS activity but actually delivers a 10-fold higher OWS activity than bulk Bi0.5Y0.5VO4 prepared by the conventional solid-state method.
关键词： Multiscale strategy,Photocatalysis,Isolated solid-solution nanocrystal,Overall water splitting,Mesoporous composite
更新于2025-09-23 15:23:52
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Miniaturized electrochemiluminescent biochip prepared on gold nanoparticles-loaded mesoporous silica film for visual detection of hydrogen peroxide released from living cells
摘要： Au nanoparticles (NPs) has been widely used for the detection of intracellular H2O2 to enhance the electron transfer process. But AuNPs are easy to aggregate in the live cells environment. Herein we report a rapid, reliable and low-cost electrochemiluminescent (ECL) biochip integrated by AuNPs-loaded mesoporous silica film (MSF) to detect H2O2 released by macrophage cells. The MSF was employed as a template to load AuNPs within the nanochannels to avoid aggregation. H2O2 could be catalyzed by AuNPs to promote the ECL reaction of luminol molecules in solution. The ECL intensity was significantly enhanced, and the peak potential was negatively shifted by 400 mV due to the excellent electrocatalytic ability of AuNPs. The integrated biochip demonstrated good reproducibility, with a wide linear range of 0.1–200 μM and an LOD of 25.3 nM. The reliability was evaluated by applying for the assessment of antioxidant activity of resveratrol using RAW 264.7 macrophage model. The AuNPs-loaded MSF integrated biochip can be easily adapted to the development of improved devices in biosensing, lab-on-a-chip, and nanofluidic systems.
关键词： Gold nanoparticles,Biochip array,Electrochemiluminescence,Reactive oxygen species,Mesoporous silica
更新于2025-09-23 15:23:52
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Improved charge separation of NiS nanoparticles modified defect-engineered black TiO2 hollow nanotubes for boosting solar-driven photocatalytic H2 evolution
摘要： NiS nanoparticles (NPs) modified black TiO2 hollow nanotubes (NBTNs) are successfully synthesized via surface hydrogenation and facile solvothermal method. The unique structure with intensified surface and interface characteristic endow NBTNs with more catalytic sites, and increase charge carrier separation efficiency with a extended charge lifetime, overwhelmingly promoting its photocatalytic performance. The resultant NBTNs possess a relatively high surface area and pore size of ~89 m2 g-1 and ~9.8 nm, respectively. The resultants NBTNs exhibit an excellent solar-driven photocatalytic hydrogen rate (3.17 mmol h-1 g-1), which almost as high as that of Pt as cocatalyst, in which the apparent quantum (AQE) yield of 5.4 % (420 nm) is recorded for the NBTNs sample. Moreover, the turnover number (TON) can be up to 116000 within 48 h. And the turnover frequency (TOF) is 2400 for NiS. This novel strategy could provide a better understanding of cocatalyst photocatalytic mechanism, and a scheme simultaneously regulating the morphology and structure of photocatalyst for promoting H2 generation.
关键词： Mesoporous TiO2 nanotube,Oxygen vacancy defect,NiS cocatalyst,Photocatalysis,Ti3+ self-doping
更新于2025-09-23 15:23:52
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Preparation of Mesoporous Fe2O3-Supported ZSM-5 Zeolites by Carbon-Templating and their Evaluation as Photo-Fenton Catalysts to Degrade Organic Pollutant
摘要： Mesoporous Fe2O3-supported ZSM-5 zeolites were prepared by carbon-templating and subsequently evaluated as photo-Fenton catalysts to degrade a dye used as a model heavy organic pollutant. The synthesis procedure of the mesoporous ZSM-5 zeolites was performed employing a nucleating gel and carbon particles as mesopores template. Thereafter, the precursor salt of the iron oxide (Fe2O3) was impregnated and then calcined to obtain the final catalyst. For comparison purposes, a conventional Fe2O3-supported ZSM-5 zeolite was also prepared. The results showed that the amount of intracrystalline mesopores formed in the ZSM-5 crystals was influenced by the amount of carbon added into the synthesis mixture. In comparison to the conventional prepared catalyst, the mesoporous Fe2O3/ZSM-5 ones showed an improved performance in the degradation of the target organic pollutant by the photo-Fenton reaction, which was attributed to the improvement of their textural properties as consequence of the mesopores generation.
关键词： Fe2O3-supported ZSM-5,Mesoporous ZSM-5,carbon template,dye degradation,photo-Fenton reaction
更新于2025-09-23 15:22:29
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The Synthesis of Mesoporous Sio2/Tio2 Composite Particles by Sol-Gel Method and Effect of Hexane on its Structural Properties
摘要： Due to their unique properties such as high surface area, uniform and adjustable pore structure, and permeability of various molecules within and on their surface, mesoporous materials have become of interest in various fields including electronics, separation, catalysis, medical applications such as implant coatings and drug delivery. Mesoporous SiO2/TiO2 particles were synthesized by sol-gel method using various amounts of surfactant cetyl tri methyl ammonium bromide (CTAB) as structure directing agent under acidic condition; moreover, hexane was applied as a swelling agent. The samples were investigated using XRD, SEM, FTIR, SEM and N2 adsorption-desorption analyses, in addition, the incremental effect of surfactant and hexane were examined. The results obtained from the analysis clarified that an increase in amount of surfactant will lead to an increase in surface area, pore size and pore volume. Additionally, with adding hexane to the constant amount of surfactant; the results showed an increase in surface area, pore size and pore volume while order of the structure was maintained.
关键词： Mesoporous,Swelling agent,N2 adsorption-desorption,Surfactant
更新于2025-09-23 15:22:29