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1.
Nanotechnology ; 35(14)2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38134436

RESUMO

Due to the misuse and overuse of the antibiotic tetracycline (TC), as well as its refractory degradability, it has become a stubborn environmental contaminant. In this study, a self-standing polyacrylonitrile-based ZIF-67@CNT/ACF aligned anodic membrane was fabricated by innovatively incorporating ZIF-67@CNT nanoparticles into an aligned carbon nanofiber (ACF) membrane to treat the TC. The flow-through nanoporous construction of the ZIF-67@CNT/ACF membrane reactor can compress the diffusion boundary layer on the electrode surface to enhance mass transfer under microscopic laminar flow, which can further enhance the degradation rate. In addition, the enhanced degradation performance also benefited from the significant electrooxidation capacity of the ZIF-67@CNT/ACF membrane. At the optimal electrocatalytic condition of 3.0 V applied potential and pH 6, the degradation rate reached 81% in 1 h for an initial TC concentration of 10 mg l-1. The refractory and highly toxic TC was electrochemically degraded into small non-toxic molecules. Our results indicate that electrocatalytic TC degradation can be enhanced by ZIF-67@CNT/ACF membrane.

2.
J Colloid Interface Sci ; 652(Pt A): 429-439, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37604054

RESUMO

The exploration of cost-effective electrocatalysts with high catalytic activity and methanol tolerance to replace precious metal catalysts in the oxygen reduction reaction (ORR) is highly desirable for direct methanol fuel cells (DMFCs). Herein, we report a novel complex composed of a CoFe alloy with a modulated electronic structure confined to nitrogen-doped carbon nanofiber (NCNF) and bamboo-like carbon nanotube (BCNT) by tuning the molar ratio of Co and Fe (CoFe@NCNF/BCNT). The synthetized catalysts possess one-dimensional (1D) mesoporous structure, high specific surface area, and rich pyridinic-N content. Notably, the Co1Fe1@NCNF/BCNT and Co1Fe3@NCNF/BCNT (Co:Fe ≈ 1:1 and 1:3) exhibited enhanced oxygen reduction activity and methanol tolerance, compared to unmodified samples. In addition, alkaline DMFCs containing Co1Fe1@NCNF/BCNT and Co1Fe3@NCNF/BCNT presented high power density (29.10 and 31.11 mW cm-2), exceeding that of Pt/C-modified DMFC (27.23 mW cm-2). Furthermore, the Co1Fe1@NCNF/BCNT-catalyzed DMFC exhibited high stability. This improved catalytic activity can be attributed to the rich surface area, controllable alloy composition, optimized N configuration, and favorable electronic interaction. The as-developed CoFe@NCNF/BCNT with multifunctional components may open a new avenue for designing highly active cathode catalysts for various fuel cells.

3.
Environ Sci Pollut Res Int ; 30(41): 93422-93434, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37561294

RESUMO

With the rapid development of the economy, energy demand is more urgent. Microbial fuel cells (MFCs) have the advantages of non-toxic, safety, and environmental protection, and are considered the ideal choice for the next generation of energy storage equipment. However, the slow kinetics of oxygen reduction reaction (ORR) on MFC air cathodes and the high cost of traditional platinum (Pt) catalysts hinder their practical application, so there is a need to develop efficient, low-cost, and stable electrocatalysts as alternatives. Recently, metal-organic framework (MOFs) has attracted wide attention in electrocatalysis. Electrocatalysts prepared by the nanocomposite of MOFs and carbon nanomaterials have multiple advantages, such as adjustable chemical properties, high specific surface area, and good electrical conductivity, which have been proven to be a promising electrocatalytic material. In this paper, the latest research progress of metal-organic frames (MOFs) and carbon nanocomposites is reviewed, and the preparation methods and modification of MOFs and carbon nanofibers, carbon nanotubes, and graphene composites are introduced, respectively, as well as their applications in MFC cathode. Finally, the main prospects of MOFs/carbon nanocomposite catalysts are put forward.


Assuntos
Fontes de Energia Bioelétrica , Estruturas Metalorgânicas , Nanocompostos , Nanotubos de Carbono , Oxirredução , Nanotubos de Carbono/química , Eletrodos
4.
J Colloid Interface Sci ; 648: 654-663, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37321084

RESUMO

Microbial fuel cells (MFCs) have great potential as a new energy technology that utilizes microorganisms to produce electrical energy by decomposing organic matter. A cathode catalyst is key to achieving an accelerated cathodic oxygen reduction reaction (ORR) in MFCs. We prepared a Zr-based metal organic-framework-derived silver-iron co-doped bimetallic material based on electrospun nanofibers by promoting the in situ growth of UiO-66-NH2 on polyacrylonitrile (PAN) nanofibers and named it as CNFs-Ag/Fe-m:n doped catalyst (m:n were 0, 1:1, 1:2, 1:3, and 2:1, respectively). Experimental results combined with density functional theory (DFT) calculations reveal that a moderate amount of Fe doped in CNFs-Ag-1:1 reduces the Gibbs free energy in the last step of the ORR. This indicates that Fe doping improves the performance of the catalytic ORR, and MFCs equipped with CNFs-Ag/Fe-1:1 exhibit a maximum power density of 737. 45 mW m-2, significantly higher than that obtained for MFCs using commercial Pt/C (457.99 mW m-2).

5.
Environ Technol ; : 1-11, 2023 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-37194302

RESUMO

Microbial fuel cell (MFC) is a promising technology for recovering energy in wastewater through bacterial metabolism. However, it always suffers from low power density and electron transfer efficiency, restricting the application. This study fabricated the MnCo2S4-Co4S3/bamboo charcoal (MCS-CS/BC) through an easy one-step hydrothermal method, and the material was applied to carbon felt (CF) to form high-performance MFC anode. MCS-CS/BC-CF anode exhibited lower Rct (10.1 Ω) than BC-CF (17.24 Ω) and CF anode (116.1 Ω), exhibiting higher electrochemical activity. MCS-CS/BC-CF anode promoted the electron transfer rate and resulted in enhanced power density, which was 9.27 times higher (980 mW m-2) than the bare CF (105.7 mW m-2). MCS-CS/BC-CF anode showed the best biocompatibility which attracted distinctly larger biomass (146.27 mg/µL) than CF (20 mg/µL) and BC-CF anode (20.1 mg/µL). The typical exoelectrogens (Geobacter and etc.) took dramatically higher proportion on MCS-CS/BC-CF anode (59.78%) than CF (2.99%) and BC-CF anode (26.67%). In addition, MCS-CS/BC stimulated the synergistic effect between exoelectrogens and fermentative bacteria, greatly favouring the extracellular electron transfer rate between bacteria and the anode and the power output. This study presented an efficient way of high-performance anode electrocatalyst fabrication for stimulating MFC power generation, giving suggestions for high-efficient energy recovery from wastewater.

6.
Environ Res ; 231(Pt 3): 116254, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37245572

RESUMO

In this work, a novel porous-structure electrochemical PbO2 filter (PEF-PbO2) was developed to achieve the reuse of bio-treated textile wastewater. The characterization of PEF-PbO2 confirmed that its coating has a variable pore size that increases with depth from the substrate, and the pores with a size of 5 µm account for the largest proportion. The study on the role of this unique structure illustrated that PEF-PbO2 possesses a larger electroactive area (4.09 times) than the conventional electrochemical PbO2 filter (EF-PbO2) and enhanced mass transfer (1.39 times) in flow mode. The investigation of operating parameters with a special discussion of electric energy consumption suggested that the optimal conditions were a current density of 3 mA cm-2, Na2SO4 concentration of 10 g L-1 and pH value of 3, which resulted in 99.07% and 53.3% removal of Rhodamine B and TOC, respectively, together with an MCETOC of 24.6%. A stable removal of 65.9% COD and 99.5% Rhodamine B with a low electric energy consumption of 5.19 kWh kg-1 COD under long-term reuse of bio-treated textile wastewater indicated that PEF-PbO2 was durable and energy-efficient in practical applications. Mechanism study by simulation calculation illustrated that the part of the pore of the PEF-PbO2's coating with small size (5 µm) plays an important role in this excellent performance which provides the advantage of rich ·OH concentration, short pollutant diffusion distance and high contact possibility.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Óxidos/química , Porosidade , Eletrodos , Poluentes Químicos da Água/análise , Têxteis , Oxirredução , Titânio/química
7.
J Colloid Interface Sci ; 646: 43-53, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37182258

RESUMO

The high catalytic activity of non-precious metals in alkaline media opens a new direction for the development of alkaline direct methanol fuel cell (ADMFC) electrocatalysts. Herein, a highly dispersed N-doped carbon nanofibers (CNFs) -loaded NiCo non-precious metal alloy electrocatalyst based on metal-organic frameworks (MOFs) was prepared, which conferred excellent methanol oxidation activity and resistance to carbon monoxide (CO) poisoning through a surface electronic structure modulation strategy. The porous electrospun polyacrylonitrile (PAN) nanofibers and the P-electron conjugated structure of polyaniline chains provide fast charge transfer channels, enabling electrocatalysts with abundant active sites and efficient electron transfer. The optimized NiCo/N-CNFs@800 was tested as an anode catalyst for ADMFC single cell and exhibited a power density of 29.15 mW cm-2. Due to the fast charge transfer and mass transfer brought by its one-dimensional porous structure and the synergistic effect between NiCo alloy, NiCo/N-CNFs@800 is expected to be an economical, efficient and CO-resistant methanol oxidation reaction (MOR) electrocatalyst.

8.
J Colloid Interface Sci ; 643: 428-436, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37086532

RESUMO

HYPOTHESIS: The relatively lower power density of Microbial fuel cells (MFCs), primarily resulting from weak biofilm habitation and sluggish extracellular electron transfer (EET) at the anode interface, limits their practical implementation on a large scale. To address this challenge, porous CoFe2O4 nanoparticles could be used as anode electrocatalysts based on the following considerations: (i) the introduction of CoFe2O4 nanoparticles endows the anode with a rough surface that facilitates biofilm formation; (ii) the positively charged Co and Fe ions improve the interfacial affinity of anodes, enabling rapid immobilization and colonization of negatively bacteria; (iii) the multi-valent metal states of Co and Fe can function as electron shuttles, mediating EET process between biofilm and anode. EXPERIMENTS: CoFe2O4 nanoparticles prepared with a bimetal-organic framework (B-MOF) as precursor, were modified to the surface of carbon cloth as the anode of MFCs. FINDINGS: MFCs equipped with CoFe2O4 anode achieved a maximum power density of 1026.68 mW m-2, which was approximately 3.4 times higher than that of the pristine carbon cloth. Additionally, the biofilm density and viability on the anode were enhanced after CoFe2O4 modification. Considering the facile fabrication process and superior electrocatalytic performance, the CoFe2O4 nanoparticles are promising electrocatalysts for high performance and cost-effective MFCs.


Assuntos
Fontes de Energia Bioelétrica , Nanopartículas , Fontes de Energia Bioelétrica/microbiologia , Eletricidade , Porosidade , Carbono , Eletrodos
9.
Artigo em Inglês | MEDLINE | ID: mdl-36901583

RESUMO

In this study, MIL-53(Fe) was innovatively incorporated into carbon felt (CF) by growing in-situ using the solvothermal method. MIL-53(Fe)@carbon felt (MIL-53(Fe)@CF) was prepared and used for the degradation of rhodamine B (RhB). As a new photocatalytic membrane, MIL-53(Fe)@CF photocatalytic membrane has the characteristics of high degradation efficiency and recyclability. Influence of various parameters including MIL-53(Fe)@CF loading, light, electron trapper type, and starting pH on RhB degradation were investigated. The morphology, structure, and degradation properties of MIL-53(Fe)@CF photocatalytic membrane were characterized. Corresponding reaction mechanisms were explored. The results indicated that pH at 4.5 and 1 mmol/L H2O2, 150 mg MIL-53(Fe)@CF could photocatalytically degrade 1 mg/L RhB by 98.8% within 120 min, and the reaction rate constant (k) could reach 0.03635 min-1. The clearance rate of RhB decreased by only 2.8% after three operations. MIL-53(Fe)@CF photocatalytic membrane was found to be stable.


Assuntos
Fibra de Carbono , Rodaminas , Carbono , Fibra de Carbono/química , Peróxido de Hidrogênio/química , Rodaminas/química , Processos Fotoquímicos
10.
Nanotechnology ; 34(24)2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-36927654

RESUMO

Znic-based metal-organic framework materials (ZIF-8) show great potential and excellent performance in the fields of sensing and catalysis. However, powdered metal-organic framework makes it easy to lose in the process of application. Herein, we use a simple blending electrostatic spinning method to combine ZIF-8 particles with polyacrylonitrile (PAN) nanofibers. ZIF-8/PAN composite nanofiber membrane. The ZIF-8/PAN nanofiber membrane is characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and N2adsorption-desorption. The results show that the ZIF-8/PAN nanofiber membrane has the characteristic peaks of XRD and FTIR, which are consistent with those of simulated ZIF-8. The specific surface area of ZIF-8/PAN nanofiber membrane increases from 13.5371 to 711.4171 m2g-1due to the introduction of ZIF-8 particles. The sensor using the nanofiber membrane as the gas sensing layer shows good response and linear correlation to different concentrations of acetone gas. The minimum detection limit of the sensor for acetone is 51.9 ppm. The blank control shows that the response of the sensor to acetone is mainly due to the introduction of ZIF-8 particles. In addition, the sensor also shows a good cyclic response to acetone.

11.
J Colloid Interface Sci ; 636: 305-316, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36638570

RESUMO

High-efficiency oxygen reduction reaction (ORR) electrocatalyst in microbial fuel cells (MFCs) is important to boost the power production efficiency and reduce overall cost. Herein, we demonstrate a novel nitrogen (N)-doped carbon nanofiber (N-CNF) supported metal and metal compound heterostructure derived from metal-organic frameworks (MOFs), which endows superior electrocatalytic activity by optimizing the coupling modulation effect. The resulting cobalt/cobalt phosphide and cobalt/cobalt sulfide nanoparticles embedded in N-doped carbon nanofiber (Co/CoP/Co2P@N-CNF, Co/CoS2@N-CNF) present superior ORR activity and methanol tolerance. Moreover, the assembled MFCs modified with Co/CoP/Co2P@N-CNF and Co/CoS2@N-CNF composite also achieve higher power density (375.16 and 400.06 mW m-2) as well as coulombic efficiency (11.2 %, 12.4 %), superior than that of Pt/C electrode (333.70 mW m-2, 10.4 %). Impressively, the Co/CoS2@N-CNF electrode exhibits long-term stability and durability in dual-chamber MFCs. A high-performance heterostructure cathode with an effective strategy for bridging nanocatalysis and practical MFCs is reported and presented.

12.
J Colloid Interface Sci ; 629(Pt B): 970-979, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36208609

RESUMO

The low power density originating from poor electroactive bacteria (EAB) adhesion and sluggish extracellular electron transfer (EET) at the anode interface, is a major impediment preventing the practical implementation of microbial fuel cells (MFCs). Tailoring the surface properties of anodes is an effective and powerful strategy for addressing this issue. In this study, we successfully fabricated an efficient anode electrocatalyst, consisting of carbon nanotubes encapsulating iron disulfide (FeS2@CNT) micropolyhedrons, using simple hydrothermal and freeze-drying methods, which not only strengthened the anode interaction with EAB but also promoted the EET process at the anode interface. As expected, the MFCs with a FeS2@CNT anode yielded an outstanding power density of 1914 mWm-2 at a current density of 4350 mA m-2, which significantly exceeded those of pure CNT (1096.2mW m-2, 2703.3 mA m-2) and carbon cloth (426.8mWm-2, 965.6 mA m-2) anodes. The high-power output can be attributed to the synergistic effect between FeS2 and CNTs, endowing the anode with biocompatibility for biofilm adhesion and colonization, nutrient diffusion, and the presence of abundant Fe and S active sites for EET mediation. Owing to the low cost, facile fabrication process, and excellent electrocatalytic performance toward the redox reactions in biofilms, the synthesized FeS2@CNT electrocatalyst is a promising material for high-performance and cost-effective MFCs with commercial applications.

13.
Environ Sci Pollut Res Int ; 29(55): 82632-82659, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36219296

RESUMO

Although membrane distillation (MD) is a promising technology for water desalination and industrial wastewater treatment, the MD process is not widely applied in the global water industry due to the lack of a suitable membrane for the MD process. The design and appropriate manufacture are the most important factors for MD membrane optimization. The well-designed porous structure, superhydrophobic surface, and pore-wetting prevention of the membrane are vital properties of the MD membrane. Nowadays, electrospinning that is capable of manufacturing membranes with superhydrophobic or omni phobic properties is considered a promising technology. Electrospun nanofibrous membranes (ENMs) possess the characteristics of cylindrical morphology, re-entrant structure, and easy-shaping for a specific purpose, benefiting the membrane design and modification. Based on that, this review investigates the current state and future progress of the superhydrophobic, multi-layer, and omniphobic ENMs manufactured with various structural designs for seawater desalination and wastewater purification. We expect that this paper will provide some recommendations and guidance for further fabrication research and the configuration design of ENMs in the MD process for seawater desalination and wastewater purification.


Assuntos
Nanofibras , Purificação da Água , Destilação , Membranas Artificiais , Água
14.
Chemosphere ; 308(Pt 2): 136434, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36113652

RESUMO

Microbial fuel cell (MFC) is a promising technology in wastewater recovery driven by microbial metabolism. However, the low power output resulting from the sluggish extracellular electron transfer (EET) between the anode surface and exoelectrogens dramatically restricted the further application. This study fabricated a high-performance anode by decorating porous and conductive electrospinning carbon nanofibers (CNFs). The maximum power density in MFC modified with 14 wt% polyacrylonitrile CNFs (M-CNF14, 9.6 ± 0.2 W m-3) was 1.9 and 2.7 times higher than carbon black modified MFC (M-CB, 5.1 ± 0.1 W m-3) and the blank (M-BA, 3.6 ± 0.1 W m-3), respectively. Denser biofilm and more microbial nanowires were observed in the M-CNF14 anode than in other conditions. Furthermore, the redox peak current of c-type cytochrome was 1.7-21 times higher in M-CNF14 than in the blank control, verifying the preferable EET activity. Several exoelectrogens like Petrimonas and Comamonas were enriched in M-CNF14 and showed a positive correlation to power generation. Besides, more simplified and modular interrelations among exoelectrogens and other bacteria were obtained in M-CNF14. This study revealed the microbial-related mechanism for simultaneously improving EET and exoelectrogens enrichment by CNFs modified anode, providing guidelines for high-performance wastewater recovery.


Assuntos
Fontes de Energia Bioelétrica , Nanofibras , Fontes de Energia Bioelétrica/microbiologia , Carbono , Citocromos , Eletricidade , Eletrodos , Elétrons , Fuligem , Águas Residuárias
15.
Sci Total Environ ; 838(Pt 2): 156007, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-35595130

RESUMO

Tetrabromobisphenol A (TBBPA), a hazardous and persistent flame retardant, has been widely detected in the natural aquatic system. The acceleration of reductive debromination (rate-limiting process) is vital during the decomposition and detoxification of TBBPA. This study achieved superior TBBPA electrochemical reductive debromination performance by nano Pd doped Ni foam electrode (4.8 times higher than Ni foam electrode). The optimal TBBPA reductive debromination performance was obtained under -1.2 V of cathode potential, 1.2 wt% of Pd loading, 10 mg L-1 of TBBPA and 100 mM of Na2SO4 as the electrolyte solution. UPLC-QTOF-MS verified that Br atoms in TBBPA were removed sequentially to form bisphenol A as the major product. Most TBBPA was reductively debrominated by atomic H* through indirect hydrodebromination, evidenced by the atomic H* quenching test. The higher solution conductivity and appropriate TBBPA concentration would contribute to the debromination efficiency. Excessive H2 generation whether by over negative potential or H atom richness electrolyte largely disturbed the reaction process and restricted the debromination. The improved generation of reductant (H*)adsPd was the most significant, while excessive Pd loading would make aggregation and limit the debromination efficiency. The study confirmed the optimization strategies of conditions for Pd/Ni foam electrode and revealed the related function mechanism for stimulating TBBPA electrochemical reduction, giving suggestions for the efficient removal of TBBPA in the aquatic environment.


Assuntos
Retardadores de Chama , Bifenil Polibromatos , Eletrodos , Bifenil Polibromatos/química
16.
Environ Technol ; 43(21): 3239-3247, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33881964

RESUMO

The removal of heavy metal ions in wastewater has a great significance to human health and environment protection. Metal organic framework possesses high surface area, rich porosity, tunable pore size and abundant active sites. However, the intrinsic aggregation and fragility of MOF nanoparticles make its poor adsorption and undesirable reusage. Herein, a facile and unique hot-pressing method is adopted to decorate the MOF nanoparticles on nickel foam (ZIF-8/NF), which simultaneously serves as self-supporting substrate of ZIF-8 nanoparticles and electrode of a self-powered multifunctional purification system. In adsorption, the ZIF-8/NF composite presents high Cu2+ removal rate of 49.5% with the concentration of 10 mg/100 ml. More importantly, integrating with electrochemistry, the Cu2+ removal rate of the ZIF-8/NF composite reaches 54.7% in 5 min. The superior performance is attributed to the comprehensive effects of ion exchange, chemical bonding and physical adsorption. Moreover, the low-cost, fast and scalable preparation contributes to commercially fabricate MOF nanoparticles on self-supported substrate to treat wastewater with high efficiency and good recyclability.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Eletroquímica , Humanos , Estruturas Metalorgânicas/química , Níquel , Águas Residuárias/química , Poluentes Químicos da Água/química
17.
Sci Total Environ ; 808: 151873, 2022 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-34838552

RESUMO

The widespread application of antibiotics have aroused serious pollution over the world. Microbial fuel cell (MFC) air cathode was able to simultaneously recover electricity and perform advanced oxidation of pollutions through electro-Fenton (EF). This study synthesized an iron­cobalt oxide and graphene composite (FeCoO/GO), which possessed high electrochemical activity and ORR catalytic performance. The uniform decoration of FeCoO/GO in MFC air cathode distinctly increased the electricity generation (4.5 times higher than carbon felt) and oxytetracycline (OTC) degradation and detoxification (1.33 times higher). FeCoO/GO boosted the H2O2 generation from ORR (1.14 times higher than CF) and mineralization efficiency of OTC (2.63 times higher than CF). UPLC-QTOF-MS verified that OTC was degraded and mineralized through decarboxylation, demethylation, and carbon ring cleavage by the oxidation of ·OH. The enhanced degradation of OTC was not only benefited from the increased ORR catalytic performance, but also the excellent H2O2 catalytic activity by Fe and Co for ·OH generation. This study demonstrated an effective strategy by decorating FeCoO/GO in MFC air cathode for the synergistically enhanced ORR and OTC degradation and detoxification, giving promising guidance for the deep removal of antibiotic pollutants in the environment.


Assuntos
Fontes de Energia Bioelétrica , Oxitetraciclina , Poluentes Químicos da Água , Eletrodos , Peróxido de Hidrogênio , Oxigênio , Poluentes Químicos da Água/análise
18.
Nanoscale ; 13(39): 16477-16486, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34605509

RESUMO

Construction of an efficient electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with low overpotential and cycling stability for lithium-oxygen batteries still remains a puzzling challenge. Herein, we propose a scalable approach to integrate ZIF derivatives into cavity porous carbon nanofibers (CPCNFs) via an electrospinning technique and thermal treatment (Zn/CoNC@CPCNFs). The ultralong interconnected nanofiber matrix is beneficial, and the developed Zn/CoNC@CPCNFs catalyst with excellent flexibility can be utilized as a free-standing electrode based on an air-cathode. Moreover, this confinement strategy ensures the dispersion of Co-based species and abundant porosity structure, which contributes to the transport and adsorption of oxygen and exposes more Co-N coordination catalytic centers, as a result of a drastically ultralow voltage gap. Consequently, a cell based on a Zn/CoNC@CPCNF electrode presents remarkably decreased charge-discharge polarization (0.36 V), a high initial discharge capacity with an ultra-low overpotential of 0.59 V, and long-term cyclability with a cut-off capacity of 0.2 mA h cm-2 at 0.02 mA cm-2. We hope that our protocol will offer instruction for the design and application of oxygen electrocatalysts for energy conversion and storage.

19.
Environ Sci Pollut Res Int ; 28(38): 54170-54176, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34405326

RESUMO

Microbial fuel cell is an efficient technology to reduce pollutants of the heavy metal ions. Herein, a dual-chamber microbial fuel cell (MFC) coupled with abio-cathode and electrochemically active bacteria is fabricated to treat Cr (VI) containing wastewater and harvest bioelectricity simultaneously. To investigate the wide application of MFC for various industries, four different concentrations of Cr (VI) (6 mg/L, 15 mg/L, 40 mg/L, 100 mg/L) are used to explore the removal efficiency of Cr (VI) and the corresponding power performance. We find that the power performance gradually increases with the increment of the initial Cr (VI) concentration. Significantly, a maximum power density of 35.3 mW/m2 can be achieved with the initial concentration of 100mg/L Cr (VI), while MFC only generate negligible power density (2.6 mW/m2) without the presence of Cr (VI). Meanwhile, MFC combined with the initial Cr (VI) concentration of 15 mg/L shows the highest Cr (VI) removal of 66.5%. Moreover, partial precipitates are found on the cathode surface and X-ray photoelectron spectroscopy (XPS) analysis has demonstrated that the Cr (VI) is successfully reduced into Cr (III). This study offers an alternative technology to remove Cr (VI) and synchronous electricity generation.


Assuntos
Fontes de Energia Bioelétrica , Cromo , Eletricidade , Eletrodos , Águas Residuárias
20.
ACS Appl Mater Interfaces ; 13(33): 39976-39984, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34379383

RESUMO

Protective fabrics with air-permeable and flexible features are crucial for practical application in the detoxification of chemical warfare agents (CWAs). Zr-based metal-organic frameworks (Zr-MOFs) are desirable to exhibit outstanding degradation toward CWAs. However, generally, MOFs with powders cannot afford the utilization as a protective layer directly; meanwhile, it is still a puzzling challenge to integrate MOFs with textiles efficiently. Herein, we develop a scalable and controllable strategy to fabricate UiO-66-NH2 on electrospun polyacrylonitrile nanofibers (UiO-66-NH2 fabrics) firmly and uniformly to capture and catalyze 2-chloroethyl ethyl sulfide (CEES) effectively for self-detoxification. The obtained UiO-66-NH2 fabrics are greatly capable of specific surface area, ample porosity, excellent crystallinity, and abundant catalytic active sites. Consequently, CEES can be removed efficiently up to 97.7% after 48 h by reaction and adsorption. The degradation products mainly including ethyl-2-hydroxyethyl sulfide, ether, bis[2-(ethylthio)ethyl], and 2-(2-(ethylthio)ethylamino) terephthalic acid are detected. Moreover, the obtained nanofibrous fabrics possess air-permeable, washable, and flexible as well as lightweight merits, totally ensuring their promising engineering applications for protective clothing.

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