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1.
J Hazard Mater ; 421: 126775, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34358971

RESUMO

Hydroquinone (HQ) and catechol (CC) are the two major dihydroxybenzene isomers, are considered one of the toxic pollutants in wastewater, which often coexisted and impede each other during sample identification. For practical analysis and simultaneous detection of HQ and CC in wastewater, we fabricate a hybrid electrochemical sensor with electrospun one-dimensional (1D) MnMoO4 nanofibers coupled with a few-layered exfoliated two-dimensional (2D) MXene. The facilitated abundant defective edges of 1D MnMoO4 and 2D MXene nanoarchitecture accelerated the effect of synergistic signal amplification and exhibited high electrocatalytic activity towards the oxidation of hydroquinone and catechol. MnMoO4-MXene-GCE showed oxidation potentials of 0.102 V and 0.203 V for hydroquinone and catechol, respectively. It revealed the distinguished and simultaneous detection range of 0.101 V with a strong anodic peak current. Noteworthily, the proposed 1D-2D hybridized MnMoO4-MXene-GCE sensor exhibited a wide linear response from 5 nM to 65 nM for hydroquinone and catechol. Moreover, it showed a low detection limit of 0.26 nM and 0.30 nM for HQ and CC with high stability, respectively. The feasible 1D-2D MnMoO4-MXene nanocomposite-based biosensor effectively detected hydroquinone and catechol in hazardous water pollutants using the differential pulse voltammetric technique with recovery values.


Assuntos
Técnicas Biossensoriais , Nanocompostos , Nanofibras , Eletrodos , Águas Residuárias
2.
Chemosphere ; 263: 128266, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297210

RESUMO

In current work, Prussian blue (PB)- and hydroxyapatite (HAp)-embedded micro-adsorbents (PB-HAp-MAs) were rationally fabricated through an easy and flexible custom-made micronozzle system as a novel bifunctional adsorbent. The adsorption performance of the as-prepared samples was conducted based on the removal of cesium (Cs+) and strontium (Sr2+) ions. Adsorption behaviors of the PB-HAp-MAs were also evaluated as function extrusion dimensions and adsorbate concentration. The adsorption isotherm was well fitted by the Langmuir model with adsorption capacities of 24.688 mg g-1 and 29.254 mg g-1 for Cs+ and Sr2+, respectively. Specially, the enhanced adsorption activity can be synergistically attributed to the porous nature of the developed alginate backbone with a high surface area of encapsulated functional nanoparticles, thus leading to rapid saturation within 1 min. In addition, the as-synthesized PB-HAp-MAs were successfully separated from the aqueous solution within 10 s by applying a magnetic field. We expect that our findings will provide valuable guidelines towards developing highly efficient adsorbents for environmental remediation.


Assuntos
Recuperação e Remediação Ambiental , Estrôncio , Adsorção , Césio , Íons/análise
3.
Nanoscale ; 12(26): 14047-14060, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32582888

RESUMO

Nanorod (NR) arrays offer commendable visible-light-driven photocatalytic performances. Herein, we describe the construction of a ternary ZnO-ZnS-Gd2S3 nanostructural array in which a sulfidation process is used to decorate a Gd2S3 shell layer with a ZnS interface over vapor-phase-grown vertically-aligned ZnO. With control over the shell-wall thickness, the shell layer of ∼25 nm wall thickness on the ultra-long ZnO NR arrays exhibited a higher catalytic efficiency close to 3.3, 2.0, 1.2, and 1.8 times those of the bare ZnO, the ZnO-ZnS, the Gd2S3-decorated (∼10 nm) and Gd2S3 shell-layered (∼40 nm) ZnO-ZnS core-shell structures, respectively. The core-shell geometry and the shell-wall thickness with maximized contact interface afforded increased light absorption in the visible region and effectively retarded the recombination rate of the photoinduced charge carriers by confining electrons and holes separately, thus providing advantages in terms of the degradation of the pharmaceutical residue tetracycline and the industrial pollutant 4-nitrophenol in wastewater.


Assuntos
Nanotubos , Óxido de Zinco , Antibacterianos , Sulfetos , Compostos de Zinco
4.
Nanotechnology ; 31(27): 275402, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32182601

RESUMO

Electrochemical water splitting represents an ideal strategy for producing clean hydrogen as an energy carrier that serves as an alternative to fossil fuels. As an effective method for hydrogen production, an efficient inexpensive multifunctional electrocatalyst with high durability is designed. Herein, we describe the heterostructural design of a three-dimensional catalytic network with self-embedded CoNi2S4 nanograins grown on electrospun carbon nanofibers (CoNi2S4-CNFs) with anchored thin-layer reduced graphene oxide. This is achieved via facile electrospinning followed by carbonization, low-temperature sulfidation, and surface functionalization. As a bifunctional catalyst, CoNi2S4-CNFs exhibited robust high activity toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium. The anchored ultrathin graphene oxide layer promoted the stability and durability of the catalytic network with an efficient path for the transportation of electrons. The rGO-anchored CoNi2S4-CNFs yielded overpotential values of 228 mV and 205 mV for the HER and OER, respectively, that drives a current density of 20 mA cm-2 in an alkaline medium. Notably, the excellent electrochemical properties are attributed to the functional effect of the CoNi2S4 on the CNF network. The ultrathin feature of rGO improved the durability of the catalytic network. Moreover, using the rGO-anchored CoNi2S4-CNFs as a cathode and anode in a two-electrode water splitting system required a cell voltage of only 1.55 V to reach a current density of 10 mA cm-2. These CNFs exhibited outstanding durability for 48 h. The present work offers new insight for the design of a catalytic network with a non-noble metal catalyst that exhibits excellent electrocatalytic activity and durability on the metal sulfides in overall water splitting.

5.
J Hazard Mater ; 391: 122249, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32097876

RESUMO

Heterogeneous photocatalysis has been proven to be a promising approach to overcome the great challenges encountered with conventional technologies for environmental remediation. Herein, for the first time, a novel hierarchical architecture of nitrogen-doped TiO2@Bi2WxMo1-xO6 (N-T@BWMO-x, x = 0-1.0) was rationally designed and fabricated through an electrospinning route followed by a solvothermal process. The photocatalytic activity of the as-prepared samples was evaluated based on the degradation of tetracycline hydrochloride (TC) under visible-light irradiation. The results indicated that the molar fraction of W/Mo has a strong impact on the photocatalytic efficiency and photoelectrochemical performance of the N-T@BWMO composites. Compared to N-TiO2 and the binary composites, N-T@BWMO-0.25 exhibited outstanding photocatalytic activity and significant cycling stability. The enhanced photocatalytic activity can be synergistically linked to the excellent native adsorption, extended light-harvesting region, hierarchical structure, and strong interfacial interaction between N-TiO2 and BWMO, which can effectively prolong the lifetime of charge-carriers. Moreover, active species-trapping and electron paramagnetic resonance results confirmed that holes and superoxide radicals were the dominant active species responsible for TC removal. A possible photocatalytic mechanism underlying the degradation of TC by N-T@BWMO-0.25 is also proposed. We expect that our findings will provide new insights into the use of highly efficient core-shell heterostructure photocatalysts, with potential applications in environmental decontamination.

6.
Nanomaterials (Basel) ; 10(2)2020 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-32050408

RESUMO

A flexible asymmetric supercapacitor (ASC) with high electrochemical performance was constructed using reduced graphene oxide (rGO)-wrapped redox-active metal oxide-based negative and positive electrodes. Thin layered rGO functionality on the positive and the negative electrode surfaces has promoted the feasible surface-active sites and enhances the electrochemical response with a wide operating voltage window. Herein we report the controlled growth of rGO-wrapped tubular FeMoO4 nanofibers (NFs) via electrospinning followed by surface functionalization as a negative electrode. The tubular structure offers the ultrathin-layer decoration of rGO inside and outside of the tubular walls with uniform wrapping. The rGO-wrapped tubular FeMoO4 NF electrode exhibited a high specific capacitance of 135.2 F g-1 in Na2SO4 neutral electrolyte with an excellent rate capability and cycling stability (96.45% in 5000 cycles) at high current density. Meanwhile, the hydrothermally synthesized binder-free rGO/MnO2 nanorods on carbon cloth (rGO-MnO2@CC) were selected as cathode materials due to their high capacitance and high conductivity. Moreover, the ASC device was fabricated using rGO-wrapped FeMoO4 on carbon cloth (rGO-FeMoO4@CC) as the negative electrode and rGO-MnO2@CC as the positive electrode (rGO-FeMoO4@CC/rGO-MnO2@CC). The rationally designed ASC device delivered an excellent energy density of 38.8 W h kg-1 with a wide operating voltage window of 0.0-1.8 V. The hybrid ASC showed excellent cycling stability of 93.37% capacitance retention for 5000 cycles. Thus, the developed rGO-wrapped FeMoO4 nanotubes and MnO2 nanorods are promising hybrid electrode materials for the development of wide-potential ASCs with high energy and power density.

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