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Functionalization of cotton fabric with bismuth oxyiodide nanosheets: applications for photodegrading organic pollutants, UV shielding and self-cleaning
摘要： A multifunctional cotton fabric was prepared by immobilizing bismuth oxyiodide (BiOI) nanosheets on the surface of cotton treated to briefly dissolve surface molecules with upon the low-temperature addition of NaOH and urea (cotton micro-dissolution). Immobilization was accomplished by successive adsorption and reaction (SILAR) at the temperature (* 25 °C). The morphology, structural characteristics, photodegradation ability for organic pollutants, UV shielding, and self-cleaning of the treated fabric were studied. The growth rate and uniformity of the BiOI nanosheets were compared between the treated fabrics and the untreated fabrics. The absorption wavelength of the cotton fabric with BiOI nanosheets was extended to the visible light (* 630 nm) region. Under visible light irradiation, cotton fabric containing BiOI nanosheets (BiOI > 8.4 wt%) showed remarkable photocatalytic ability for degrading rhodamine B (RhB) with a degradation rate of 99% (C0 = 20 mg/L) and 95% after the first and sixth cycle, respectively. The ultraviolet protection factor (UPF) of cotton fabric with BiOI nanosheets was > 50, and its transmittance of ultraviolet A (T(UVA)) was < 5%. The cotton fabric with BiOI nanosheets also exhibited superhydrophobic and self-cleaning properties. Thus, the cotton fabric with BiOI nanosheets has great potential for application as a multifunctional protective material.
关键词： BiOI nanosheets,Visible-light photocatalytic activity,Superhydrophobicity,Ultraviolet protection factor
更新于2025-09-19 17:15:36
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Fluorescence sensor for facile and visual detection of organophosphorus pesticides using AIE fluorogens-SiO2-MnO2 sandwich nanocomposites
摘要： Organophosphorus pesticides (OPs) are frequently for pest control in the agriculture industry. Accumulation of OPs is harmful to the environment and human health. Thus, facile and portable detection of organophosphorus pesticides is of great importance. Among these methods, the fluorescence assay holds the advantages of high sensitivity, simplicity, nondestructive properties. Conventional fluorophores have the drawbacks of poor photostability and low signal-to-noise ratio due to their aggregation-caused quenching drawbacks at high concentration or in the aggregate state. Aggregation-induced emission fluorogens (AIEgens) are one key to develop next-generation fluorescence sensor due to their high emission efficiency in the aggregated state. 1,2-bis[4-(3-sulfonatopropoxyl) phenyl]-1,2-diphenylethene (BSPOTPE) is a typical AIE molecule containing two hydroxyl group. In this study, a fluorescence sensor based on BSPOTPE-SiO2–MnO2 sandwich nanocomposites was fabricated. Thiocholine (TCh), which produced from acetylthiocholine(ATCh) by the hydrolysis of acetylcholinesterase (AChE), can “turn on” the fluorescence sensor. Based on the inhibition effect of OPs on AChE activity and the corresponding “turn off” effect on the fluorescence sensor, an AIE-based assay for OPs determination was developed. The fabricated sensor for paraoxon determination has a good linear relationship in the range of 1–100 μg/L and the LOD of 1 μg/L. Moreover, a simple, convenient fluorescence strip for visual semi-quantitative of OPs was fabricated, indicating this “on-off” fluorescent sensor is promising for on-site and infield detection.
关键词： Organophosphorus pesticide,AIE fluorogen,Fluorescence sensor,MnO2 nanosheets
更新于2025-09-19 17:15:36
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A Comparative Study of Particle Size Distribution of Graphene Nanosheets Synthesized by an Ultrasound-Assisted Method
摘要： Graphene-based materials are highly interesting in virtue of their excellent chemical, physical and mechanical properties that make them extremely useful as privileged materials in different industrial applications. Sonochemical methods allow the production of low-defect graphene materials, which are preferred for certain uses. Graphene nanosheets (GNS) have been prepared by exfoliation of a commercial micrographite (MG) using an ultrasound probe. Both materials were characterized by common techniques such as X-ray diffraction (XRD), Transmission Electronic Microscopy (TEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). All of them revealed the formation of exfoliated graphene nanosheets with similar surface characteristics to the pristine graphite but with a decreased crystallite size and number of layers. An exhaustive study of the particle size distribution was carried out by different analytical techniques such as dynamic light scattering (DLS), nanoparticle tracking analysis (NTA) and asymmetric flow field flow fractionation (AF4). The results provided by these techniques have been compared. NTA and AF4 gave higher resolution than DLS. AF4 has shown to be a precise analytical technique for the separation of GNS of different sizes.
关键词： exfoliation,graphene nanosheets,nanoparticle tracking analysis,asymmetric flow field flow fractionation,particle size distribution
更新于2025-09-19 17:15:36
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ZnO Nanosheets Abundant in Oxygen Vacancies Derived from Metal-Organic Frameworks for ppb-Level Gas Sensing
摘要： Surmounting the inhomogeniety issue of gas sensors and realizing their reproducible ppb-level gas sensing are highly desirable for widespread deployments of sensors to build networks in applications of industrial safety and indoor/outdoor air quality monitoring. Herein, a strategy is proposed to substantially improve the surface homogeneity of sensing materials and gas sensing performance via chip-level pyrolysis of as-grown ZIF-L (ZIF stands for zeolitic imidazolate framework) films to porous and hierarchical zinc oxide (ZnO) nanosheets. A novel approach to generate adjustable oxygen vacancies is demonstrated, through which the electronic structure of sensing materials can be fine-tuned. Their presence is thoroughly verified by various techniques. The sensing results demonstrate that the resultant oxygen vacancy-abundant ZnO nanosheets exhibit significantly enhanced sensitivity and shortened response time toward ppb-level carbon monoxide (CO) and volatile organic compounds encompassing 1,3-butadiene, toluene, and tetrachloroethylene, which can be ascribed to several reasons including unpaired electrons, consequent bandgap narrowing, increased specific surface area, and hierarchical micro–mesoporous structures. This facile approach sheds light on the rational design of sensing materials via defect engineering, and can facilitate the mass production, commercialization, and large-scale deployments of sensors with controllable morphology and superior sensing performance targeted for ultratrace gas detection.
关键词： metal-organic frameworks,oxygen vacancies,ppb-level gas sensing,defect engineering,ZnO nanosheets
更新于2025-09-19 17:15:36
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Soluble g-C3N4 nanosheets: facile synthesis and application in photocatalytic hydrogen evolution
摘要： The high dispersibility and solubility are highly required for the potential applications and development of well-known g-C3N4 material. In this study, a facile hydrothermal treatment and the following vacuum freezing-drying process was developed to synthesize the g-C3N4 nanosheets (ca. 5 nm) with excellent dispersibility and solubility in aqueous solutions. It was found that the melem structures with many hydrophilic groups (-NH2, -OH and -C=O) were formed on the g-C3N4 nanosheet surface, resulting in the formation of soluble g-C3N4 (SCN) nanosheets. Moreover, the SCN nanosheets can be worked as the effective modifier to greatly increase the H2-production performance of conventional g-C3N4 photocatalyst (the resultant sample was referred to SCN/g-C3N4). Photocatalytic results revealed that the SCN/g-C3N4 sample exhibited a remarkably higher H2-production performance than the pure g-C3N4 by a factor of ca. 2. The improved H2-production rate of SCN/g-C3N4 photocatalysts could be primarily ascribed to the introduction of hydrophilic groups, which not only remarkably enhances the dispersibility and hydrophilicity of SCN/g-C3N4, but also work as the interfacial active sites to accelerate the H+-reduction reaction and the rapid formation of H2. The present soluble g-C3N4 nanosheets provide potential various applications in environmental protection and energy conversion fields.
关键词： photocatalysis,H2-evolution,solubility,g-C3N4 nanosheets,dispersibility
更新于2025-09-19 17:15:36
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Ag NPs modified plasmonic Z-scheme photocatalyst Bi4Ti3O12/Ag/Ag3PO4 with improved performance for pollutants removal under visible light irradiation
摘要： In a typical Z-scheme photocatalytic system, the visible light responsive component typically plays a crucial role and is often confined to materials sensitive to visible light. In addition, metallic nanodots or quantum dots are used as effective cocatalysts in the construction of plasmonic Z-scheme photocatalysts because of their strong light harvesting capacities under visible light illumination. In the present study, Bi4Ti3O12 nanosheets dominated with (001) crystal planes were successfully prepared via a facile molten-salt method, and BTO/Ag/APO composite samples were prepared by a simple precipitation method followed by photoreduction. The obtained BTO/Ag/APO composite exhibits improved photocatalytic activity for the decontamination of two typical organic pollutants, compared to bare Bi4Ti3O12 and Ag3PO4. Based on various characterization techniques, a Z-scheme electron transfer mechanism induced by the plasmonic effect was hypothesized to clarify the enhanced catalytic performances in this system. On the other hand, the LSPR effect of deposited silver nanoparticles can boost the molecular oxygen activation process and generate more superoxide radicals. This study provides a promising approach to apply highly effective photocatalytic degradation for environmental remediation.
关键词： Localized surface plasmonic resonance,Ag3PO4 nanospheres,Bi4Ti3O12 nanosheets,Photocatalysis
更新于2025-09-19 17:13:59
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Mesoporous NiCo2O4 network constructed from ultrathin-mesoporous nanosheets as high performance electrocatalyst in dye sensitized solar cell
摘要： Three-dimensional (3D) mesoporous network provides favorable structural features for ion diffusion, electroactive sites and contact with electrolyte, but fabricating the 3D networks of transition metal oxides is still challenging. Based upon template-free method, NiCo2O4 network constructed from ultrathin mesoporous nanosheets (NiCo2O4 MNN) was designed and synthesized. NiCo2O4 nanosheets (~5 nm of thickness, 2~5 nm of pore diameters) are highly interlaced with each other to form a 3D network and create porous nanostructure. Benefiting from the specific structural advantages, NiCo2O4 MNN delivers superior electrocatalytic performance as counter electrode (CE) in dye sensitized solar cell (DSSC), with a higher power conversion efficiency (PCE) of 8.05 % than Pt electrode (7.32 %). We believe that this research will open a new avenue for the design and development of efficient and cost-effective metal oxides electrocatalysts in DSSC.
关键词： electrocatalytic performance,mesoporous network,ultrathin-mesoporous nanosheets,NiCo2O4,template-free synthesis
更新于2025-09-19 17:13:59
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Carbon quantum dots implanted CdS nanosheets: Efficient visible-light-driven photocatalytic reduction of Cr(VI) under saline conditions
摘要： Chromium(VI) (Cr(VI)), a toxic metal, is generally present together with ionic salts in industrial effluents. An efficient reduction of Cr(VI) to Cr(III) in saline water is an imperative issue but still a challenging task. Literature has rarely addressed reducing Cr(VI) effectively under saline conditions. Herein, carbon quantum dots (CQDs) were successfully implanted in the CdS nanosheets (CdS-NSs) to prepare nanocomposites (i.e., CCNs) for the first time to efficiently reduce Cr(VI) to Cr(III). The newly fabricated CCNs demonstrated superior performance to reduce Cr(VI) compared to pristine CdS-NSs and CQDs-deposited CdS nanosheets (i.e., CQD/CdS-NSs) in saline water. The nanostructures were examined by spectral and photoelectrochemical measurements as well as density functional theory (DFT) calculations. Results showed that CCNs facilitated the photo-electron transport and thus suppressed charge recombination via formation of micro-regional heterostructures. A lower band gap of CCNs relative to pristine CdS-NSs and CQD/CdS-NSs extended the light absorption spectrum. The optimal photocatalyst, denoted as CCNs-2, exhibited an efficiency of ~94% for photocatalytic Cr(VI) reduction within 10 min in water containing 1200 mg/L salts. The obtained rate constant of reduction of Cr(VI) was (2.62 ± 0.04) × 10-1 min-1, approximately 4 and 3 times higher than that of pristine CdS-NSs and CQD/CdS-NSs, respectively. After 3 cycles, the CCNs-2 still showed an efficiency of ~78% aqueous Cr(VI) reduction within 10 min. Our results clearly presented that implantation relative to deposition of CQDs for CdS-NSs is a preferential strategy to enhance photocatalytic Cr(VI) reduction in saline water under visible light irradiation.
关键词： Saline water,Implantation,Photocatalytic Cr(VI) reduction,Carbon quantum dots,Cadmium sulfide nanosheets
更新于2025-09-19 17:13:59
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Boosting the photocatalytic ability of g-C3N4 for hydrogen production by Ti3C2 MXene quantum dots
摘要： The big challenging issues in photocatalytic H2 evolution are efficient separation of the photoinduced carriers, the stability of the catalyst, enhancing quantum efficiency and requiring photoinduced electrons enrich on photocatalysts’ surface. Herein, Ti3C2 MXene quantum dots (QDs) possess the activity of Pt as co-catalyst in promotion the photocatalytic H2 evolution to form heterostructure with g-C3N4 nanosheets (NSs) (denoted as g-C3N4@Ti3C2 QDs). The photocatalytic H2 evolution rate of g-C3N4@Ti3C2 QDs composite with an optimized Ti3C2 QDs loading amounts (100 mL) is nearly 26, 3 and 10 times higher than pristine g-C3N4 NSs, Pt/g-C3N4, Ti3C2 MXene sheet/g-C3N4, respectively. The Ti3C2 QDs increase the specific surface area of g-C3N4 and boost the density of active site. Besides, metallic Ti3C2 QDs possess excellent electronic conductivity, causing the improvement of carrier transfer efficiency.
关键词： Ti3C2 MXene quantum dots,Photocatalytic H2 production,g-C3N4 nanosheets,co-catalysts
更新于2025-09-19 17:13:59
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Solar-blind deep-ultraviolet photodetectors based on solution-synthesized quasi-2D Te nanosheets
摘要： Solar-blind deep ultraviolet (DUV) photodetectors with high responsivity (R) and fast response speed are crucial for practical applications in astrophysical analysis, environmental pollution monitoring, and communication. Recently, 2D tellurium has emerged as a potential optoelectronic material because of its excellent photoelectric properties. In this study, solar-blind DUV photodetectors are demonstrated based on solution-synthesized and air-stable quasi-2D Te nanosheets (Te NSs). An R of 6.5×104 A/W at 261 nm and an external quantum efficiency (EQE) of higher than 2.26×106% were obtained, which are highest among most other 2D material-based solar-blind DUV photodetectors. Moreover, the photoelectric performance of the quasi-2D Te-based photodetector exhibited good stability even after ambient exposure for 90 days without any encapsulation. These results indicate that quasi-2D Te NSs provide a viable approach for developing solar-blind DUV photodetectors with ultrahigh R and EQE.
关键词： FET,photodetector,solar-blind deep ultraviolet,quasi-2D Te nanosheets
更新于2025-09-19 17:13:59