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Sol–Gel Spin-Coating Followed by Solvothermal Synthesis of Nanorods-Based ZnO Thin Films: Microstructural, Optical, and Gas Sensing Properties
摘要： Zinc oxide thin films with nanorod morphology were investigated for microstructural and optical properties as well as their performance as a liquid petroleum gas sensing material. A two-step synthesis procedure consisting of sol–gel spin-coating and solvothermal methods was employed where several factors such as rational utilization of metal precursors, solvent, stabilizing, and structure directing agents, a repetitive drying-coating process, as well as post-thermal annealing were found influential to obtain qualified nanorods and a final homogeneous thin film. Compositional and optical investigations were pursued to characterize features, namely morphology, poly crystallinity, porous structure, nanocrystallite size, lattice oriented growth, textural atomic ratio, lattice purity and transparency, phonon and exciton transitions, as well as the formed structural defects via field-emission scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray, UV–Vis spectroscopy, Raman, and photoluminescence techniques. The as-prepared thin film was then used as an active LPG sensing material via a home-made gas sensor where the control sensing parameters were chamber testing temperature and gas concentration. Results showed a quantitative response of 92.7% as sensor sensitivity at an operation temperature of 250°C and a LPG concentration of 800 ppm in addition to fast response and recovery times of 44.1 s and 218.7 s, respectively.
关键词： Zinc oxide nanorods,thin film,optical characteristics,gas sensing,microstructural properties,liquid petroleum gas
更新于2025-09-23 15:23:52
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Characterization of atypical polyaniline nano-structures prepared via advanced techniques
摘要： Conductive polymers had been the topic of a vast number of investigations during the last decades, so, the synthesis of conducting polymers and study of their physical properties has been of prime importance. One of these conductive polymers is polyaniline. The current work is to prepare polyaniline (PANI) nanostructured material via four different preparation techniques which were sol-gel, rapid mixing, sonochemical and supercritical carbon dioxide (SC-CO2) assisted polymerization. The morphology of the prepared PANI samples was determined using Transmission electron microscopy (TEM) and Scanning Electron Microscope (SEM). The molecular structure of prepared PANI samples was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The electrical conductivity of the synthesized samples was assessed by using the four-probe method at room temperature. The surface area of the prepared samples was determined using Brunauer Emmett Teller (BET). The characterization results of the prepared PANI con?rm that the morphology, chemical composition, crystallinity, conductivity and surface area were altered signi?cantly as a consequence of its synthesis via atypical techniques.
关键词： Supercritical carbon dioxide assisted polymerization,Nanoparticles,Sonochemical,Polyaniline nano-structures,Nano?bers,Polyaniline characterization,Nanorods,Sol gel,Rapid mixing polymerization
更新于2025-09-23 15:23:52
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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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In-Situ covalent synthesis of gold nanorods on GO surface as ultrasensitive Raman probe
摘要： In this paper, using thiolated graphene oxide (GO‐O‐SH) as substrate, gold nanorods (AuNRs) covalently linked to the GO surface by in‐situ seed growth method were first reported. The as‐prepared composites were characterized by UV–vis spectrum, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR). Experimental results indicated that the introduction of short flexible organic chain between GO and AuNRs contributed to the homogenous synthesis of gold rods, and uniform gold nanorods with aspect ratio within 3~8 were covalently linked to the surface of GO with high stability and yield. The strategy represented an outstanding improvement in comparison to the traditional route for fabricating the two GO@AuNRs composites. Furthermore, based on coupling of nanomaterials, the composites could act as high sensitive Raman probe with limit of detection (LOD) reaching 1 × 10?12 M.
关键词： covalent synthesis,Raman probe,graphene oxide (GO),gold nanorods
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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ZnIn2S4 nanosheets decorating WO3 nanorods core-shell hybrids for boosting visible-light photocatalysis hydrogen generation
摘要： We here report the fabrication of a core-shell WO3@ZnIn2S4 heterostructure by an interfacial seeding growth strategy, which is implemented by direct growth of ZnIn2S4 nanosheets on the surface of WO3 nanorods with forming a strong electronic interaction between two semiconductors that are beneficial for promoting the interfacial charge transfer. Systematic studies demonstrate that the WO3@ZnIn2S4 nanohybrids hold superior performance for photocatalytic hydrogen generation under visible light irradiation with a production rate of 3900 mmol g-1 h-1. This work provides an effective approach to construct the direct Z-scheme photocatalytic systems for efficient photocatalytic hydrogen evolution, which would be significant for the design of more direct Z-scheme system for various photocatalytic applications.
关键词： ZnIn2S4 nanosheets,WO3 nanorods,Photocatalytic H2 generation,Visible light,Z-scheme
更新于2025-09-23 15:23:52
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Optical limiting property of gold nanorods/ormosil gel glass composites
摘要： Sol–gel derived ormosil gel glass can act as matrix for different functional molecules or nanomaterials due to its many advantages. Gold and silver colloidal nanoparticles have great application potential in nonlinear optical field due to their ultrafast optical response. In this letter, the nanocomposites of gold nanorods and ormosil gel glass were prepared by a solvent-assisted dispersing process and characterized by UV–vis spectra, TEM, XRD and optical limiting measurement. The results showed that these gold/ormosil nanocomposites could preserve optical limiting property of gold nanorods and had enhanced thermostability due to thermostable silica matrix. Such nanocomposite material of metal-doped gel glass matrix could be considered as a promising candidate for optical limiter against tunable laser.
关键词： Nanocomposites,Optical limiting,Ormosil gel glass,Thermostability,Gold nanorods
更新于2025-09-23 15:23:52
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Structural and optical properties of porous ZnO nanorods synthesized by a simple two-step method
摘要： The porous ZnO nanorods were successfully synthesized by a two-step template free method consisting of a modified hydrothermal approach and subsequent annealing treatment. Additive formaldehyde was adopted in the initial hydrothermal approach. Numerous mesopores with orderly distribution along the c axis apparently appeared in the annealed products. It is suggested that formaldehyde might adsorb in ZnO nanorods during the hydrothermal process and decompose under elevated temperature. The release of the generated gas prompted the formation of the pores. A schematic model was proposed to describe the forming of pores in ZnO nanorods. Further investigation demonstrated that the emission behavior and crystallographic quality may highly depend on the annealing temperature. The intensity ratio of the ultraviolet emission peak and visible emission peak as well as the crystallographic quality fluctuates due to the competition of the forming of pores and annealed temperature. The samples annealed at 450 °C possess high crystallographic quality and large surface area, which may be the suitable candidate for highly effective photocatalyst and ZnO based photoelectric devices.
关键词： Annealing,Porous nanorods,Photoluminescence,ZnO
更新于2025-09-23 15:23:52
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A personalized and long-acting local therapeutic platform combining photothermal therapy and chemotherapy for the treatment of multidrug-resistant colon tumor
摘要： Background: Local photothermal therapy (PTT) provides an easily applicable, noninvasive adjunctive therapy for colorectal cancer (CRC), especially when multidrug resistance (MDR) occurs. However, using PTT alone does not result in complete tumor ablation in many cases, thus resulting in tumor recurrence and metastasis. Materials and methods: In this study, we aim to develop a personalized local therapeutic platform combining PTT with long-acting chemotherapy for the treatment of MDR CRC. The platform consists of polyethylene glycol (PEG)-coated gold nanorods (PEG-GNRs) and d-alpha-tocopheryl PEG 1000 succinate (TPGS)-coated paclitaxel (PTX) nanocrystals (TPGS-PTX NC), followed by the incorporation into an in situ hydrogel (gel) system (GNRs-TPGS-PTX NC-gel) before injection. After administration, PEG-GNRs can exert quick and efficient local photothermal response under near-infrared laser irradiation to shrink tumor; TPGS-PTX NC then provides a long-acting chemotherapy due to the sustained release of PTX along with the P-glycoprotein inhibitor TPGS to reverse the drug resistance. Results: The cytotoxicity studies showed that the IC50 of GNRs-TPGS-PTX NC-gel with laser irradiation decreased to ~178-folds compared with PTX alone in drug-resistant SW620 AD300 cells. In the in vivo efficacy test, after laser irradiation, the GNRs-TPGS-PTX NC-gel showed similar tumor volume inhibition compared with GNRs-gel at the beginning. However, after 14 days, the tumor volume of the mice treated with GNRs-gel quickly increased, while that of the mice treated with GNRs-TPGS-PTX NC-gel remained controllable due to the long-term chemotherapeutic effect of TPGS-PTX NC. The mice treated with GNRs-TPGS-PTX NC-gel also showed no weight loss and obvious organ damages and lesions during the treatment, indicating a low systemic side effect profile and a good biocompatibility. Conclusion: Overall, the nano-complex may serve as a promising local therapeutic patch against MDR CRC with one-time dosing to achieve a long-term tumor control. The doses of PEG-GNRs and TPGS-PTX NC can be easily adjusted before use according to patient-specific characteristics potentially making it a personalized therapeutic platform.
关键词： in situ hydrogel,tumor recurrence,gold nanorods,paclitaxel nanocrystals,TPGS
更新于2025-09-23 15:23:52
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Functional chlorin gold nanorods enable to treat breast cancer by photothermal/photodynamic therapy
摘要： Background: The existing chemo/radiotherapy fail to eliminate cancer cells due to the restriction of either drug resistance or radio tolerance. The predicament urges researchers to continuously explore alternative strategy for achieving a potent curative effect. Methods: Functional chlorin gold nanorods (Ce6-AuNR@SiO2-d-CPP) were fabricated aiming at treating breast cancer by photothermal/photodynamic therapy (PTT/PDT). The nanostructure was developed by synthesizing Au nanorods as the photothermal conversion material, and by coating the pegylated mesoporous SiO2 as the shell for entrapping photosensitizer Ce6 and for linking the D-type cell penetrating peptide (d-CPP). The function of Ce6-AuNR@SiO2-d-CPP was verified on human breast cancer MCF-7 cells and MCF-7 cells xenografts in nude mice. Results: Under combinational treatment of PTT and PDT, Ce6-AuNR@SiO2-d-CPP demonstrated a strong cytotoxicity and apoptosis inducing effects in breast cancer cells in vitro, and a robust treatment efficacy in breast cancer-bearing nude mice. The uptake mechanism involved the energy-consuming caveolin-mediated endocytosis, and Ce6-AuNR@SiO2-d-CPP in PTT/PDT mode could induce apoptosis by multiple pathways in breast cancer cells. Conclusion: Ce6-AuNR@SiO2-d-CPP demonstrated a robust efficacy in the treatment of breast cancer by photothermal/photodynamic therapy. Therefore, the present study could offer a new promising strategy to treat the refractory breast cancer.
关键词： PTT/PDT,apoptosis,cellular uptake,functional chlorin gold nanorods,cell penetrating peptide,cytotoxicity
更新于2025-09-23 15:23:52