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1.
Chemosphere ; 366: 143413, 2024 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-39332581

RESUMO

Conventional water treatment processes often fail to effectively remove antibacterial drugs, necessitating advanced strategies. This study presents the synthesis of novel floating, visible light-active α-NiMoO4/mpg-C3N4/EP composites for the removal of ciprofloxacin (CFX), a widely used quinolone antibiotic, from water. These composites are easily recoverable, highly stable, and demonstrate excellent reusability. The optimal photocatalyst, NC-101/EP (α-NiMoO4/mpg-C3N4 = 10:1), achieved 96.2 ± 1.1% degradation of CFX at 1.6 g L-1 within 80 min under visible light, significantly outperforming previous benchmarks. This high efficiency is attributed to the formation of interfacial junctions and a built-in electric field, which enhanced charge transfer and hydroxyl radical generation through an S-scheme mechanism. Fluorescence spectroscopy provided precise monitoring of CFX degradation without interference from coexisting intermediates. Density functional theory (DFT) calculations revealed that hydroxyl radicals initiated highly favorable and spontaneous oxidation of CFX, with a reaction rate constant of 6.04 × 109 M-1 s-1. The preferred oxidation pathway followed the sequence: HO-addition > H-abstraction > single electron transfer. Four degradation pathways were identified, with key intermediates confirmed by high-resolution mass spectrometry. The process also significantly reduced CFX toxicity, ensuring minimal environmental impact. These findings position NC-101/EP as a promising photocatalyst for large-scale water treatment applications targeting antibiotic contamination.

2.
Int J Biol Macromol ; 278(Pt 2): 134707, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39147339

RESUMO

Herein, we report for the first time a simple strategy to design a hierarchical chemically exfoliated magnesium diboride and guar gum network structure decorated with Ru nanoparticles (eMgB2-GG@Ru) as an electrode to evaluate its electrochemical performance for the application of supercapacitor. The eMgB2 and functionalized eMgB2-GG@Ru materials were thoroughly examined using XRD, TGA, DLS, FE-SEM, STEM, AFM, XPS, and BET techniques. The combined eMgB2-GG@Ru electrode exhibits a network structure morphology with an increased interlayer distance of eMgB2 nanolayers along with a uniform distribution of spherical Ru nanoparticles. The electrochemical performance of eMgB2-GG@Ru and its pristine materials was studied through CV, GCD, and EIS to determine their supercapacitor performance. The eMgB2-GG@Ru electrode demonstrates higher specific capacitance (352 F/g) than its eMgB2@Ru (258.9 F/g), and MgB2 (214.5 F/g) counterparts at a current density of 0.5 A/g in a three-electrode setup using 3 M KOH electrolyte. The hierarchical eMgB2-GG@Ru solid-state symmetric devices maintained higher capacity retention of 89 % even after 7000 cycles, achieving a maximum energy density of 26.12 kW/kg at the power density of 450 W/kg at 0.5 A/g. Therefore, the innovative eMgB2-GG@Ru electrode offers superior electrochemical performance with efficient electrolyte ion mobility for energy storage applications.


Assuntos
Capacitância Elétrica , Eletrodos , Galactanos , Mananas , Nanocompostos , Gomas Vegetais , Rutênio , Gomas Vegetais/química , Nanocompostos/química , Galactanos/química , Rutênio/química , Mananas/química , Técnicas Eletroquímicas , Compostos de Magnésio/química
3.
Adv Sci (Weinh) ; 11(31): e2401386, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38894575

RESUMO

Since two-dimensionalal (2D) materials have distinct chemical and physical properties, they are widely used in various sectors of modern technologies. In the domain of diagnostic biodevices, particularly for point-of-care (PoC) biomedical diagnostics, 2D-based field-effect transistor biosensors (bio-FETs) demonstrate substantial potential. Here, in this review article, the operational mechanisms and detection capabilities of biosensing devices utilizing graphene, transition metal dichalcogenides (TMDCs), black phosphorus, and other 2D materials are addressed in detail. The incorporation of these materials into FET-based biosensors offers significant advantages, including low detection limits (LOD), real-time monitoring, label-free diagnosis, and exceptional selectivity. The review also highlights the diverse applications of these biosensors, ranging from conventional to wearable devices, underscoring the versatility of 2D material-based FET devices. Additionally, the review provides a comprehensive assessment of the limitations and challenges faced by these devices, along with insights into future prospects and advancements. Notably, a detailed comparison of FET-based biosensors is tabulated along with various other biosensing platforms and their working mechanisms. Ultimately, this review aims to stimulate further research and innovation in this field while educating the scientific community about the latest advancements in 2D materials-based biosensors.


Assuntos
Técnicas Biossensoriais , Sistemas Automatizados de Assistência Junto ao Leito , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Humanos , Transistores Eletrônicos , Grafite/química , Desenho de Equipamento
4.
Dalton Trans ; 53(26): 10961-10973, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38814155

RESUMO

Polymer-like dielectrics with superb thermal conductivity as well as high dielectric properties hold great promise for the modern electronic field. Nevertheless, integrating these properties into a single material simultaneously remains problematic due to their mutually limited physical connotations. In this study, we developed high-quality thermally conductive epoxy composites with excellent dielectric properties. This was achieved by incorporating surface-functionalized microscale hexagonal boron nitride (BN) along with N-[3-(Trimethoxysilyl)propyl]ethylene diamine (DN) and N-[3-(Trimethoxysilyl)propyl]aniline (PN). In the resulting epoxy composite, microscale BN serves as the primary building block for establishing the thermally conductive network, while silica particles act as bridges to regulate heat transfer and reduce interfacial phonon-scattering. The prepared composites were thoroughly examined across various filler contents (ranging from 10 to 80 wt%). Among them, the DNBN/epoxy composite exhibited higher thermal conductivity (in-plane: 47.03 W m-1 K-1) at 60 wt% filler content compared to BN/epoxy (39.40 W m-1 K-1) and PNBN/epoxy (33 W m-1 K-1) composites. These results highlight the usefulness of surface modification of BN in improving compatibility between fillers and epoxy, ultimately reducing composite viscosity. Furthermore, the DNBN/epoxy composite at 60 wt% demonstrated superb dielectric constant (∼6.15) without compromising on dissipation loss (∼0.06). The strategy adopted in this study offers significant insights into designing dielectric thermally conductive composites with superior performance outcomes.

5.
J Environ Sci (China) ; 144: 212-224, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38802232

RESUMO

In this work, the perovskite LaZnO3 was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole (SMZ) antibiotics under visible light activation. SMZ was almost completely degraded (99.2% ± 0.3%) within 4 hr by photocatalyst LaZnO3 at the optimal dosage of 1.1 g/L, with a mineralization proportion of 58.7% ± 0.4%. The efficient performance of LaZnO3 can be attributed to its wide-range light absorption and the appropriate energy band edge levels, which facilitate the formation of active agents such as ·O2-, h+, and ·OH. The integration of RP-HPLC/Q-TOF-MS and DFT-based computational techniques revealed three degradation pathways of SMZ, which were initiated by the deamination reaction at the aniline ring, the breakdown of the sulfonamide moieties, and a process known as Smile-type rearrangement and SO2 intrusion. Corresponding toxicity of SMZ and the intermediates were analyzed by quantitative structure activity relationship (QSAR), indicating the effectiveness of LaZnO3-based photocatalysis in preventing secondary pollution of the intermediates to the ecosystem during the degradation process. The visible-light-activated photocatalyst LaZnO3 exhibited efficient performance in the occurrence of inorganic anions and maintained high durability across multiple recycling tests, making it a promising candidate for practical antibiotic treatment.


Assuntos
Antibacterianos , Luz , Óxidos , Sulfametizol , Titânio , Poluentes Químicos da Água , Antibacterianos/química , Titânio/química , Óxidos/química , Sulfametizol/química , Poluentes Químicos da Água/química , Compostos de Cálcio/química , Catálise , Fotólise , Modelos Químicos
6.
Chemosphere ; 356: 141972, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38608780

RESUMO

Metal-organic frameworks (MOFs) have emerged as a key focus in water treatment and monitoring due to their unique structural features, including extensive surface area, customizable porosity, reversible adsorption, and high catalytic efficiency. While numerous reviews have discussed MOFs in environmental remediation, this review specifically addresses recent advancements in modifying MOFs to enhance their effectiveness in water purification and monitoring. It underscores their roles as adsorbents, photocatalysts, and in luminescent and electrochemical sensing. Advancements such as pore modification, defect engineering, and functionalization, combined synergistically with advanced materials, have led to the development of recyclable MOF-based nano-adsorbents, Z-scheme photocatalytic systems, nanocomposites, and hybrid materials. These innovations have broadened the spectrum of removable contaminants and improved material recyclability. Additionally, this review delves into the creation of multifunctional MOF materials, the development of robust MOF variants, and the simplification of synthesis methods, marking significant progress in MOF sensor technology. Furthermore, the review addresses current challenges in this field and proposes potential future research directions and practical applications. The growing research interest in MOFs underscores the need for an updated synthesis of knowledge in this area, focusing on both current challenges and future opportunities in water remediation.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Purificação da Água , Estruturas Metalorgânicas/química , Purificação da Água/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Adsorção , Recuperação e Remediação Ambiental/métodos , Catálise , Nanocompostos/química
7.
RSC Adv ; 14(1): 118-130, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38173577

RESUMO

Exploring larger surface area electrode materials is crucial for the development of an efficient supercapacitors (SCs) with superior electrochemical performance. Herein, a cost-effective strategy was adopted to synthesize a series of ZIF8 nanocrystals, and their size effect as a function of surface area was also examined. The resultant ZIF8-4 nanocrystal exhibits a uniform hexagonal structure with a large surface area (2800 m2 g-1) and nanometre size while maintaining a yield as high as 78%. The SCs performance was explored by employing different aqueous electrolytes (0.5 M H2SO4 and 1 M KOH) in a three-electrode set-up. The SC performance using a basic electrolyte (1 M KOH) was superior owing to the high ionic mobility of K+. The optimized ZIF8-4 nanocrystal electrode showed a faradaic reaction with a highest capacitance of 1420 F g-1 at 1 A g-1 of current density compared to other as-prepared electrodes in the three-electrode assembly. In addition, the resultant ZIF8-4 was embedded into a symmetric supercapacitor (SSC), and the device offered 350 F g-1 of capacitance with a maximum energy and power density of 43.7 W h kg-1 and 900 W kg-1 at 1 A g-1 of current density, respectively. To determine the practical viewpoint and real-world applications of the ZIF8-4 SSC device, 7000 GCD cycles were performed at 10 A g-1 of current density. Significantly, the device exhibited a cycling stability around 90% compared to the initial capacitance. Therefore, these findings provide a pathway for constructing large surface area ZIF8-based electrodes for high-value-added energy storage applications, particularly supercapacitors.

8.
Adv Sci (Weinh) ; 10(33): e2303654, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37863822

RESUMO

The exclusive features of two-dimensional (2D) semiconductors, such as high surface-to-volume ratios, tunable electronic properties, and biocompatibility, provide promising opportunities for developing highly sensitive biosensors. However, developing practical biosensors that can promptly detect low concentrations of target analytes remains a challenging task. Here, a field-effect-transistor comprising n-type transition metal dichalcogenide tin disulfide (SnS2 ) is developed over the hexagonal boron nitride (h-BN) for the detection of streptavidin protein (Strep.) as a target analyte. A self-designed receptor based on the pyrene-lysine conjugated with biotin (PLCB) is utilized to maintain the sensitivity of the SnS2 /h-BN FET because of the π-π stacking. The detection capabilities of SnS2 /h-BN FET are investigated using both Raman spectroscopy and electrical characterizations. The real-time electrical measurements exhibit that the SnS2 /h-BN FET is capable of detecting streptavidin at a remarkably low concentration of 0.5 pm, within 13.2 s. Additionally, the selectivity of the device is investigated by measuring its response against a Cow-like serum egg white protein (BSA), having a comparative molecular weight to that of the streptavidin. These results indicate a high sensitivity and rapid response of SnS2 /h-BN biosensor against the selective proteins, which can have significant implications in several fields including point-of-care diagnostics, drug discovery, and environmental monitoring.


Assuntos
Técnicas Biossensoriais , Transistores Eletrônicos , Animais , Bovinos , Feminino , Estreptavidina , Técnicas Biossensoriais/métodos , Dissulfetos , Semicondutores
9.
Beilstein J Nanotechnol ; 14: 964-970, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37766914

RESUMO

The increasing recognition of the impact of CO2 emissions as a global concern, directly linked to the rise in global temperature, has raised significant attention. Carbon capture and storage, particularly in association with adsorbents, has occurred as a pivotal approach to address this pressing issue. Large surface area, high porosity, and abundant adsorption sites make metal-organic frameworks (MOFs) promising contenders for CO2 uptake. This review commences by discussing recent advancements in MOFs with diverse adsorption sites, encompassing open metal sites and Lewis basic centers. Next, diverse strategies aimed at enhancing CO2 adsorption capabilities are presented, including pore size manipulation, post-synthetic modifications, and composite formation. Finally, the extant challenges and anticipated prospects pertaining to the development of MOF-based nanomaterials for CO2 storage are described.

10.
Int J Biol Macromol ; 253(Pt 3): 126948, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37722634

RESUMO

Today, dyes/pigment-based materials are confronting a serious issue in harming marine ecology. Annihilate these serious water pollutants using photoactive 2D nanohybrid catalysts showed promising comparativeness over available photocatalysts. In the present work, a facile route to decorate Ruthenium (Ru) on 2D MgB2 flower-like nanostructures was developed via ecofriendly guar gum biopolymer substantial template (MgB2/GG@Ru NFS) and its photocatalytic performance was reported. Synthesis of MgB2@Ru, MgB2/GG@Ru NFS and commercial MgB2, was studied by FTIR, XRD, FE-SEM, EDX, AFM, TEM, UV-vis spectra, and XPS analysis. From the results, the MgB2/GG@Ru NFS exhibited a superior photocatalytic performance (99.7 %) than its precursors MgB2@Ru (79.7 %), and MgB2 (53.7 %), with the degradation efficiency of the crystal violet (CV) within 100 min under visible light irradiation. The proposed photo-catalyst MgB2/GG@Ru NFS showed negligible loss of photocatalytic activity even after five successive cycles, revealing its reusability and enhanced stability due to the network structure. The photocatalytic mechanism for MgB2/GG@Ru NFS was evaluated by trapping experiment of active species, verifying that superoxide (O2-) and electron (e-) contributed significant role in the dye degradation.


Assuntos
Nanoestruturas , Rutênio , Violeta Genciana , Luz , Nanoestruturas/química , Corantes/química
11.
Nanomaterials (Basel) ; 13(10)2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37242026

RESUMO

Utilizing zeolitic imidazolate frameworks (ZIFs) poses a significant challenge that demands a facile synthesis method to produce uniform and nanometer-scale materials with high surface areas while achieving high yields. Herein, we demonstrate a facile and cost-effective strategy to systematically produce ZIF8 nanocrystals. Typically, ZIF8 nanocrystal synthesis involves a wet chemical route. As the reaction time decreased (150, 120, and 90 min), the size of the ZIF8 crystals decreased with uniform morphology, and productivity reached as high as 89%. The composition of the product was confirmed through XRD, FE-SEM, TEM, EDS, and Raman spectroscopy. The ZIF8 synthesized with different reaction time was finally employed for catalyzing the electrochemical hydrogen evaluation reaction (HER). The optimized ZIF8-3 obtained at 90 min of reaction time exhibited a superior catalytic action on the HER in alkaline medium, along with a remarkably long-term stability for 24 h compared with the other ZIF8 nanocrystals obtained at different reaction times. Specifically, the optimized ZIF8-3 sample revealed an HER overpotential of 172 mV and a Tafel slope of 104.15 mV·dec-1. This finding, thus, demonstrates ZIF8 as a promising electrocatalyst for the production of high-value-added green and sustainable hydrogen energy.

12.
RSC Adv ; 12(52): 33653-33665, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36505717

RESUMO

The preparation of sunblocks with dispersion stability, ultraviolet blocking, and photocompatibility remains a considerable challenge. Plant-derived natural polymers, such as cellulose nanofibers (CNF), show versatile traits, including long aspect ratio, hydrophilic nature, resource abundance, and low material cost. In the present study, a facile and cost-effective strategy is reported for the fabrication of nanostructured inorganic materials by incorporating natural polymers as interspersed, systematically nanosized titanium dioxide (TiO2) particles onto CNF. Among all experiments, the optimized TiO2@CNF3 showed higher ultraviolet blocking performance and less whitening effect. The outstanding performance is attributed to the engineering of equally dispersed nano-sized TiO2 particles on the CNF surface and stable dispersion. Significantly, TiO2@CNF3 exhibited excellent compatibility with avobenzone (80%), an oil-soluble ingredient used in sunblock products, illustrating the photoprotection enhancement under ultraviolet A (UVA) and ultraviolet B (UVB). Moreover, only 14.8% rhodamine B (Rho-B) dye degraded through photocatalytic oxidation process with the TiO2@CNF3, which is negligible photocatalytic activity compared to that of TiO2 (95% dye degraded). Furthermore, commercial inorganic and organic sunblock products with SPF lifetimes of 35+ and 50+ were modified using CNF, significantly enhancing the transmittance performance compared to that of the pure sunblock. However, it was also observed that hydrophilic CNF tended to demulsify the creams due to electrostatic disequilibrium. This CNF-based modified TiO2 system is a new window to replace effective sunblock products in high-value-added applications, such as cosmetics.

13.
Dalton Trans ; 51(38): 14775, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36131626

RESUMO

Correction for 'Fabrication of Fe3O4-incorporated MnO2 nanoflowers as electrodes for enhanced asymmetric supercapacitor performance' by Iqra Rabani et al., Dalton Trans., 2022, https://doi.org/10.1039/D2DT01942F.

14.
Dalton Trans ; 51(37): 14190-14200, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36056677

RESUMO

Manganese dioxide (MnO2) is considered a promising aspirant for energy storage materials on account of its higher theoretical capacitance along with low capital cost. However, its performance is generally limited by its poor lifespan and intrinsic conductivity. In this study, MnO2-incorporated iron oxide (Fe3O4) nanoflowers were synthesized through a facile hydrothermal route and their electrochemical performance was probed. The surface composition and morphology of the as-synthesized samples were confirmed using X-ray diffraction, X-ray photoemission spectroscopy, and field emission scanning microscopy. The nanoflower-like structure and synergistic effect between the two oxides of the as-prepared MnO2@Fe3O4 nanocomposite electrode result in desirable surface area and intrinsic conductivity. Owing to its higher surface area and electrical conductivity, the MnO2@Fe3O4 nanoflower-like nanocomposite exhibits an enhanced specific capacitance (Cs) of 1651 F g-1 (1 A g-1) in a three-electrode test cell, which is two-fold higher than those of pristine Fe3O4 and MnO2. In addition, an asymmetric supercapacitor (ASC) was readily constructed by sandwiching a cellulose membrane (separator) between MnO2@Fe3O4 (cathode) and activated carbon (anode). Significantly, the ASC displayed a high Cs of 131 F g-1 (1 A g-1) along with a pretty high cycling stability of 96% over 5000 cycles at 15 A g-1 and a high energy density of 46.6 Wh kg-1 at 0.8 kW kg-1. These results demonstrate the significant potential of the MnO2@Fe3O4 nanoflower ASC device for state-of-the-art futuristic advanced energy storage applications.

15.
Ultrason Sonochem ; 90: 106177, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36174271

RESUMO

Semiconductor-based photocatalysis is one of the favorable techniques for the wastewater treatment. Herein, we synthesized the activated carbon-decorated cerium dioxide (AC-CeO2) nanocomposites via the facile ultrasonication method by using the biomass-derived AC nanoflakes and the sonochemically-synthesized CeO2 nanoparticles. The AC-CeO2 nanocomposites exhibited the aggregated morphology with the AC nanoflakes-anchored CeO2 nanoparticles. Since the hybridization of conductive AC and semiconductive CeO2 would lead to the increased photocarrier transport and the reduced photocarrier recombination, during the photocatalytic reaction, the AC-CeO2 nanocomposites showed the enhanced crystal violet dye-degradation efficiency up to 97.9 % within 135 min. The results suggest that the AC-CeO2 nanocomposites hold promise as a prominent photocatalyst for future green environmental technology.


Assuntos
Violeta Genciana , Nanocompostos , Nanocompostos/química , Catálise
16.
Sci Total Environ ; 843: 157010, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35772558

RESUMO

Interactions between microplastics (MPs) and humic substances (HS) are inevitable in MP-contaminated aquatic environment because of the ubiquitous presence of HS. In this study, we explored the effects of abiotic and biotic aging processes on the adsorption behavior of aquatic HS on MPs. Aging experiments were conducted using polyethylene (PE) as a representative MP, in which UV irradiation and microbial incubation were applied for 15 to 18 days to mimic the natural abiotic and biotic aging processes. Surface modifications after the aging treatments were evidenced by the appearance of CO, CO, O-C=O, and -OH groups; the formation of grooves on UV-aged PE; and the formation of biofilms on the surface of bio-aged PE. The specific surface areas of both treated PE MPs increased with aging. Higher HS adsorption on PE surface was observed after the aging treatments, with a highest kinetic rate for UV-aged PE than that for bio-aged PE. The adsorption isotherm models revealed that the aging processes enhanced the HS adsorption tendency, as evidenced by the highest adsorption capacity for UV-aged PE (~187 µg C/m2), followed by bio-aged PE (~157 µg C/m2) and pristine PE (~87.5 µg C/m2) for a comparable extended aging period (15-18 days). The difference was more pronounced at a lower pH. The enhanced HS adsorption was mainly attributed to the formation of hydrogen bonds, whereas HS adsorption on pristine PE was dominated by hydrophobic interactions and weak van der Waals interactions. Among the two identified fluorescent components (terrestrial humic-like C1 and protein-like C2), C1 exhibited a higher affinity for adsorption onto PE irrespective of aging. Our findings provide insights into the substantial changes that occur in the interactions between MPs and aquatic organic matter with aging processes, which may alter the fate and environmental impacts of MPs in many aquatic systems.


Assuntos
Microplásticos , Poluentes Químicos da Água , Adsorção , Substâncias Húmicas , Plásticos , Polietileno/química , Poluentes Químicos da Água/análise
17.
Nanomaterials (Basel) ; 12(3)2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35159681

RESUMO

This work reports the fabrication of vanadium sulfide (VS2) microflower via one-step solvo-/hydro-thermal process. The impact of ethylene glycol on the VS2 morphology and crystal structure as well as the ensuing influences on electrocatalytic hydrogen evolution reaction (HER) and supercapacitor performance are explored and compared with those of the VS2 obtained from the standard pure-aqueous and pure-ethylene glycol solvents. The optimized VS2 obtained from the ethylene glycol and water mixed solvents exhibits a highly ordered unique assembly of petals resulting a highly open microflower structure. The electrode based on the optimized VS2 and exhibits a promising HER electrocatalysis in 0.5 M H2SO4 and 1 M KOH electrolytes, attaining a low overpotential of 161 and 197 mV, respectively, at 10 mA.cm-2 with a small Tafel slope 83 and 139 mVdec-1. In addition, the optimized VS2 based electrode exhibits an excellent electrochemical durability over 13 h. Furthermore, the superior VS2 electrode based symmetric supercapacitor delivers a specific capacitance of 139 Fg-1 at a discharging current density of 0.7 Ag-1 and exhibits an enhanced energy density of 15.63 Whkg-1 at a power density 0.304 kWkg-1. Notably, the device exhibits the capacity retention of 86.8% after 7000 charge/discharge cycles, demonstrating a high stability of the VS2 electrode.

18.
Environ Res ; 205: 112201, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655605

RESUMO

To materialize the excellent photocatalyst for crystal violet dye-degradation, the graphitic carbon-encapsulated vanadium pentoxide (GC-V2O5) nanocomposites were synthesized through the simple sonication method by using the green tea waste-derived GC nanoflakes and the sonochemically synthesized V2O5 nanorods. The nanocomposites were confirmed to comprise an aggregated morphology, in which the orthorhombic V2O5 nanorods were well anchored with the intertwingled GC nanoflakes. Owing to the encapsulation of defective V2O5 by conductive GC, the GC-V2O5 nanocomposites exhibited the enhanced photocatalytic dye-degradation efficiency up to 98.4% within 105 min. Namely, the encapsulated GC nanosheets might compensate the native defects (i.e., charge traps) on the V2O5 surface; hence, the charge transport could be enhanced during the dye-degradation process while the photocarrier recombination could be suppressed. The results suggest the conducting layer-encapsulated semiconducting oxide nanocomposites (e.g., GC-V2O5) to be of good use for future green environmental technology, particularly, as a superb photocatalyst for dye degradation.


Assuntos
Grafite , Nanocompostos , Carbono , Catálise , Violeta Genciana , Grafite/química
19.
J Colloid Interface Sci ; 606(Pt 2): 1792-1799, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34507170

RESUMO

Energy storage characteristics of organic molecules continue to attract attention for supercapacitor applications, as they offer simple processing and can be employed for flexible devices. The current study utilized the ultrasonically driven exfoliation to obtain poly diketo pyrrolopyrrole-thieno thiophene (PDPT) and multiwalled carbon nanotube (CNT) composite, subsequently fabricated a PDPT donor-π-acceptor heterojunction with CNT and investigated energy storage applications. The composite was characterized using series of standard analytical techniques. Morphology indicated well alighted CNT tubes on PDPT polymer nanosheets with an effective interface, providing efficient electrochemical regions, enabling fast charge transfer between PDPT and CNT. We also investigated the PDPT-CNT composite electrochemical behavior, achieving 319.2 and 105.7F.g-1 capacitances for PDPT-CNT and PDPT at 0.5 A.g-1 current density for three electrode configurations; and 126 and 42F.g-1 for symmetric structures, respectively. Experimental results confirmed that PDPT-CNT composite electrodes achieved two fold the capacitance compared with PDPT alone. The hypothesis and synthetic approach provide an excellent candidate for conjugated polymers with carbon nanotubes and energy related devices.

20.
J Colloid Interface Sci ; 608(Pt 3): 2347-2357, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34763888

RESUMO

Water pollution via hazardous organic pollutants poses a high threat to the environment and globally imperils aquatic life and human health. Therefore, the elimination of toxic organic waste from water sources is vital to ensure a healthy green environment. In the current work, we synthesized α-MnO2-Fe3O4 3D-flower like structure using a two-step hydrothermal method and explored the combination in a visible-light-assisted photocatalytic degrdation of dyes. The attained high specific surface area of 82 m2/g with mesoporous nature of α-MnO2 and Fe3O4 together can generate more active sites after exposure to visible light, leading to remarkable photodegradation performance. Significantly, twofold higher dye (methylene blue, MB (94.8%/120 min; crystal violet, CV (93.7%/120 min)) and drug (LVO 91%/90 min) photodegradations were observed with α-MnO2-Fe3O4 as catalyst than pure α-MnO2 and Fe3O4 at pH 6, respectively. This is attributed to the higher surface area and synergistic effect between Mn and Fe. More than 85% stability was observed with optimized catalysts employing MB and CV dyes, demonstrating the excellent reusability of the α-MnO2-Fe3O4. The underlying mechanism indicates that the formation of reactive oxygen species predominantly plays a role in the photodegradation of dyes under visible light. Consequently, these new insights will shed light on the practical applications of the α-MnO2-Fe3O4 3D-flower-like spherical structure for eco-friendly remediation via wastewater treatment.


Assuntos
Compostos de Manganês , Óxidos , Compostos Férricos , Humanos , Luz
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