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1.
ChemSusChem ; : e202400808, 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39163552

RESUMEN

Developing active sites with flexibility and diversity is crucial for single atom catalysts (SACs) towards sustainable nitrogen fixation at ambient conditions. Herein, the effects of doping main group metal elements (MGM) on the stability, catalytic activity, and selectivity of vanadium-based SACs is systematically investigated based on density functional theory calculations. It is found that the catalytic activity of V site can be significantly enhanced by the synergistic effect between MGM and vanadium atoms. More importantly, a volcano curve between the catalytic activity and the adsorption free energy of NNH* can be established, in which V-Pb dimer embedded on N-coordinated graphene (VPb-NG) exhibits optimal NRR activity due to its location at the top of volcano. Further analysis of electronic structures reveals that the unoccupancy ratio (eg/t2g) of V site is dramatically increased by the strong d-p orbital hybridization between V and Pb atoms, subsequently, N2 is activated to a larger extent. These interesting findings may provide a new path for designing active sites in SACs with excellent performance.

2.
Biomed Chromatogr ; 38(8): e5943, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38890009

RESUMEN

In this study, a targeted nanocarrier was developed by functionalizing graphene oxide with polyethyleneimine and folic acid, intended for loading oridonin. The nanocarrier was successfully synthesized and characterized using an ultraviolet spectrum, Fourier transform infrared spectroscopy and scanning electron microscopy. The nanocarrier demonstrated a remarkable oridonin loading capacity, reaching 424.8 µg/mg, as determined by ultra-high performance liquid chromatography. In vitro drug release experiments exhibited a pH-dependent release profile, with a higher cumulative release in an acidic environment. The release mechanism followed the Ritger-Peppas equation model. Cytotoxicity assays indicated minimal toxicity of the nanocarrier. Enhanced cellular uptake by MCF7 cells was observed for carriers functionalized with folate and polyethyleneimine. These findings highlight the potential of functionalized graphene oxide as a promising carrier for oridonin delivery in biomedical applications.


Asunto(s)
Neoplasias de la Mama , Diterpenos de Tipo Kaurano , Portadores de Fármacos , Grafito , Grafito/química , Diterpenos de Tipo Kaurano/química , Diterpenos de Tipo Kaurano/farmacología , Humanos , Células MCF-7 , Portadores de Fármacos/química , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Antineoplásicos/farmacología , Antineoplásicos/química , Liberación de Fármacos , Supervivencia Celular/efectos de los fármacos , Ácido Fólico/química , Nanopartículas/química , Cromatografía Líquida de Alta Presión/métodos
3.
Nanomaterials (Basel) ; 14(7)2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38607103

RESUMEN

The high energy consumption of traditional water splitting to produce hydrogen is mainly due to complex oxygen evolution reaction (OER), where low-economic-value O2 gas is generated. Meanwhile, cogeneration of H2 and O2 may result in the formation of an explosive H2/O2 gas mixture due to gas crossover. Considering these factors, a favorable anodic oxidation reaction is employed to replace OER, which not only reduces the voltage for H2 production at the cathode and avoids H2/O2 gas mixture but also generates value-added products at the anode. In recent years, this innovative strategy that combines anodic oxidation for H2 production has received intensive attention in the field of electrocatalysis. In this review, the latest research progress of a coupled hydrogen production system with pollutant degradation/upgrading is systematically introduced. Firstly, wastewater purification via anodic reaction, which produces free radicals instead of OER for pollutant degradation, is systematically presented. Then, the coupled system that allows for pollutant refining into high-value-added products combined with hydrogen production is displayed. Thirdly, the photoelectrical system for pollutant degradation and upgrade are briefly introduced. Finally, this review also discusses the challenges and future perspectives of this coupled system.

4.
J Colloid Interface Sci ; 663: 992-1004, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38452548

RESUMEN

The construction of CN/UiO-67 (CNU) S-scheme heterojunction composites through in situ formation of UiO-67 on carbon nitride (C3N4) helps to address the limitations of carbon nitride (CN) in photocatalytic NO elimination. The optimized CNU3 demonstrates superior photocatalytic efficiency, which is attributed to electronic channels constructed by Zr-N bonds and S-scheme electron transport mechanism, effectively promoting the efficient separation of photogenerated charge carriers with high redox potentials. Density Functional Theory (DFT) calculations reveal redistributed electronic orbitals in CNU3, with progressive and continuous energy levels near the Fermi level, which bolsters electronic conduction. Comprehensive quenching experiments, Electron Paramagnetic Resonance (EPR), and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analyses highlight a synergistic interplay of electrons, holes, and superoxide radicals in CNU3, inhibiting the generation of toxic nitrogen oxide intermediates and culminating in highly efficient photocatalytic NO oxidation. This study not only elucidates the mechanisms underpinning the enhanced performance of CNU3 heterojunctions but also offers new perspectives on the preparation and interfacial charge separation of heterojunction photocatalysts.

5.
Materials (Basel) ; 17(4)2024 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-38399089

RESUMEN

Zn-ion hybrid supercapacitors (ZHCs) combining merits of battery-type and capacitive electrodes are considered to be a prospective candidate in energy storage systems. Tailor-made carbon cathodes with high zincophilicity and abundant physi/chemisorption sites are critical but it remains a great challenge to achieve both features by a sustainable means. Herein, a hydrogen-bonding interaction-guided self-assembly strategy is presented to prepare iodine-doped carbon nanocages without templates for boosting zinc-ion storage by nucleophilicity. The biomass ellagic acid contains extensional hydroxy and acyloxy groups with electron-donating ability, which interact with melamine and ammonium iodide to form organic supermolecules. The organic supermolecules further self-assemble into a nanocage-like structure with cavities under hydrothermal processes via hydrogen-bonding and π-π stacking. The carbon nanocages as ZHCs cathodes enable the high approachability of zincophilic sites and low ion migration resistance resulting from the interconnected conductive network and nanoscale architecture. The experimental analyses and theoretical simulations reveal the pivotal role of iodine dopants. The I5-/I3- doping anions in carbon cathodes have a nucleophilicity to preferentially adsorb the Zn2+ cation by the formation of C+-I5--Zn2+ and C+-I3--Zn2+. Of these, the C+-I3- shows stronger bonding with Zn2+ than C+-I5-. As a result, the iodine-doped carbon nanocages produced via this template-free strategy deliver a high capacity of 134.2 mAh/g at 1 A/g and a maximum energy and power density of 114.1 Wh/kg and 42.5 kW/kg.

6.
J Mater Chem B ; 11(40): 9712-9720, 2023 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-37791404

RESUMEN

The development of organic dyes with emission peaks in the second near-infrared window (NIR-II 1000-1700 nm) is highly desirable for in vivo imaging and imaging-guided phototheranostics. However, the lack of appropriate molecular frameworks and the challenges associated with complex synthesis critically hinder the development of new candidate fluorophores. J-Aggregation is considered as a smart and straightforward way to construct such a therapeutic agent with NIR-II fluorescence imaging properties. Here, we present the design and synthesis of an aza-BODIPY probe (TA). Upon encapsulation within the amphiphilic polymer DSPEG-PEG2000-NH2, TA underwent self-assembly and formed J-aggregates (TAJ NPs), which showed emission at 1020 nm. High spatial resolution and adequate signal-to-noise ratio of the TAJ NPs are demonstrated for noninvasive bioimaging of the vasculature, lymph nodes and bones of mice in the NIR-II region. Moreover, the TAJ NPs exhibited good tumor enrichment efficiency with reduced liver accumulation and significant imaging-guided phototherapy performance against lung cancer cells. Taken together, this work not only introduces a new NIR-II imaging and phototheranostic agent based on J-aggregates, but also provides insight into the development of versatile organic dyes for future clinical implementation.


Asunto(s)
Nanopartículas , Neoplasias , Animales , Ratones , Nanopartículas/química , Neoplasias/terapia , Compuestos de Boro , Colorantes Fluorescentes/química
7.
Psychol Res Behav Manag ; 16: 2201-2211, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37337564

RESUMEN

Introduction: Studies have shown that Chinese language learning anxiety among international students in China can negatively affect their psychological adjustment. However, the specific effects and conditions of learning anxiety need to be further investigated. This study explored the mediating effects between Chinese language learning anxiety and psychological adjustment of international students in China. Methods: Chinese Learning Anxiety Scale, Campus Adaptability Scale for International Students in China, Academic Resilience Questionnaire for International Students in China, Zung's Self-Rated Depression Scale were administered to 307 international students from Nanjing Normal University in China, including 165 male students and 131 female students, aged 19-28 (M =21.42; SD = 1.528). Results: Chinese language learning anxiety significantly predicted the psychological well-being of international students after controlling for gender and age variables. Furthermore, Chinese language learning anxiety predicted the mental health of students through the independent mediating effect of campus adaptation and academic resilience, as well as the chain mediating effect of campus adaptation and academic resilience. Conclusion: The study has theoretical and practical significance for improving international students' psychological adaptation and health, and implications for those involved in the management and teaching of international students in China. The research conclusions are as follows: firstly, when the Chinese learning anxiety of international students in China is strong, their campus adaptation and psychological resilience are reduced, and levels of depression increase; secondly, grades are significantly correlated with anxiety dimensions, and higher grades are associated with lower anxiety levels; finally, the mediating effects of campus adaptation and academic resilience were significant, together with a significant chain mediating effect of campus adaptation and academic resilience.

8.
Materials (Basel) ; 16(7)2023 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-37049003

RESUMEN

Electrocatalytic water splitting for hydrogen (H2) production has attracted more and more attention in the context of energy shortages. The use of scarce pure water resources, such as electrolyte, not only increases the cost but also makes application difficult on a large scale. Compared to pure water electrolysis, seawater electrolysis is more competitive in terms of both resource acquisition and economic benefits; however, the complex ionic environment in seawater also brings great challenges to seawater electrolysis technology. Specifically, chloride oxidation-related corrosion and the deposition of insoluble solids on the surface of electrodes during seawater electrolysis make a significant difference to electrocatalytic performance. In response to this issue, design strategies have been proposed to improve the stability of electrodes. Herein, basic principles of seawater electrolysis are first discussed. Then, the design strategy for corrosion-resistant electrodes for seawater electrolysis is recommended. Finally, a development direction for seawater electrolysis in the industrialization process is proposed.

9.
Small ; 19(25): e2208045, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36929607

RESUMEN

Alkaline membrane water electrolysis is a promising production technology, and advanced electrocatalyst and membrane electrode design have always been the core technology. Herein, an ion-exchange method and an environmentally friendly in situ green phosphating strategy are successively employed to fabricate Ru-Ru2 P heterogeneous nanoparticles by using hydroxyapatite (HAP) as a phosphorus source, which is an exceptionally active electrocatalyst for hydrogen evolution reaction (HER). Density functional theory calculation results reveal that strong electronic redistribution occurs at the heterointerface of Ru-Ru2 P, which modulates the electronic structure to achieve an optimized hydrogen adsorption strength. The obtained Ru-Ru2 P possesses excellent HER performance (24 mV at 10 mA cm-2 ) and robust stability (1000 mA cm-2 for 120 h) in alkaline media. Furthermore, an environmentally friendly membrane electrode with a sandwich structure is assembled by HAP nanowires as an alkaline membrane, Ru-Ru2 P as a cathodic catalyst, and NiFe-LDH as an anodic catalyst, respectively. The voltage of (-) Ru-Ru2 P || NiFe-LDH/CNTs (+) (1.53 V at 10 mA cm-2 ) is lower than that of (-) 20 wt% Pt/C || RuO2 (+) (1.60 V at 10 mA cm-2 ) for overall water splitting. Overall, the studies not only design an efficient catalyst but also provide a new route to achieve a high-stability electrolyzer for industrial H2 production.

10.
Small ; 18(44): e2204827, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36148861

RESUMEN

The rational design for transition metals-based carbon nano-materials as efficient electrocatalysts still remains a crucial challenge for economical electrochemical hydrogen production. Carbon nanotubes (CNTs) as attractive electrocatalysts are typically activated by non-metal dopant to promote catalytic performance. Metals doping or metal/non-metal co-doping of CNTs, however, are rarely explored. Herein, this work rationally designs bimetal oxide templates of ZnCo2 O4 for heterogeneously doping Zn and N into Co nanoparticles embedded carbon nanotubes (Co@Zn-N-CNTs). During the formation of CNTs, Zn atoms volatilize from ZnCo2 O4 and in situ dope into the carbon skeleton. In particular, owing to the low electronegativity of Zn, the electrons aptly transfer from Zn to carbon atoms, which generate a high electron density for the carbon layers and offer more preponderant catalytic sites for hydrogen reduction. The Co@Zn-N-CNTs catalyst exhibits enhanced hydrogen evolution reaction activity in 0.5 m H2 SO4 electrolyte, with a low onset potential of -20 mV versus RHE at 1 mA cm-2 , an overpotential of 67 mV at 10 mA cm-2 , a small Tafel slope of 52.1 mV dec-1 , and persistent long-term stability. This study provides brand-new insights into the utilization of Zn as electronic regulator and activity promoter toward the design of high-efficiency electrocatalysts.

11.
Adv Sci (Weinh) ; 9(10): e2105869, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35112811

RESUMEN

Transition metal nitrides have shown large potential in industrial application for realization of the high active and large current density toward overall water splitting, a strategy to synthesize an inexpensive electrocatalyst consisting of Ni nanoparticles embedded metallic MoN microrods cultured on roughened nickel sheet (Ni/MoN/rNS) through underfocus laser heating on NiMoO4 ·xH2 O under NH3 atmosphere is posited. The proposed laser preparation mechanism of infocus and underfocus modes confirms that the laser induced stress and local high temperature controllably and rapidly prepared the patterned Ni/MoN/rNS electrodes in large size. The designed Ni/MoN/rNS presents outstanding catalytic performance for hydrogen evolution reaction (HER) with a low overpotential of 67 mV to deliver a current density of 10 mA cm-2 and for the oxygen evolution reaction (OER) with a small overpotential of 533 mV to deliver 200 mA cm-2 . Density functional theory (DFT) calculations and Kelvin probe force microscopy (KPFM) further verify that the constructed interface of Ni/MoN with small hydrogen absorption Gibbs free energy (ΔGH* ) (-0.19 eV) and similar electrical conductivity between Ni and metallic MoN, which can explain the high intrinsic catalytic activity of Ni/MoN. Further, the constructed two-electrode system (-) Ni/MoN/rNS||Ni/MoN/rNS (+) is employed in an industrial water-splitting electrolyzer (460 mA cm-2 for 120 h), being superior to the performance of commercial nickel electrode.

12.
Bioengineered ; 12(1): 392-401, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-33472509

RESUMEN

This study developed a novel method for the rapid detection of Escherichia coli (E. coli) O157:H7 on a microfluidic platform. First, the concentration of bacteria in a sample was determined with the adenosine triphosphate (ATP) method. Then, the specific detection of E. coli was achieved in a microfluidic chip by the immune-microsphere technique. The influences of the culture time, flow rate and capture time on the detection of the target bacteria were investigated systematically. Generally, with increasing capture time, more bacteria could be captured by the microspheres, which had a positive effect on bacterial detection. Furthermore, the sensitivity and specificity of the method were also tested. The results showed that this method could specifically detect E. coli with a sensitivity as high as 49.1 cfu/µL; the consumption of bacteria was 1 µL, and the reagent was at the microliter level. The testing time can be controlled within one and a half hours, and the cost of testing was approximately RMB 10. The method described in this article is simple and accurate and has great application value in bacterial detection for medical diagnostics.


Asunto(s)
Anticuerpos Antibacterianos/metabolismo , Escherichia coli O157/aislamiento & purificación , Técnicas Analíticas Microfluídicas , Microesferas , Adenosina Trifosfato/metabolismo , Anticuerpos Antibacterianos/química , Anticuerpos Inmovilizados , Carga Bacteriana/métodos , Técnicas de Tipificación Bacteriana/métodos , Escherichia coli O157/inmunología , Escherichia coli O157/metabolismo , Dispositivos Laboratorio en un Chip , Técnicas Analíticas Microfluídicas/instrumentación , Técnicas Analíticas Microfluídicas/métodos
13.
Adv Sci (Weinh) ; 7(17): 2001526, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32995134

RESUMEN

Water splitting for production of hydrogen as a clean energy alternative to fossil fuel has received much attention, but it is still a tough challenge to synthesize electrocatalysts with controllable bonding and charge distribution. In this work, ultrafine S-doped RuP nanoparticles homogeneously embedded in a N, P, and S-codoped carbon sheet (S-RuP@NPSC) is synthesized by pyrolysis of poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) as the source of C/N/S/P. The bondings between Ru and N, P, S in PZS are regulated to synthesize RuS2 (800 °C) and S-RuP (900 °C) by different calcination temperatures. The S-RuP@NPSC with low Ru loading of 0.8 wt% with abundant active catalytic sites possesses high utilization of Ru, the mass catalytic activity is 22.88 times than 20 wt% Pt/C with the overpotential of 250 mV. Density functional theory calculation confirms that the surface Ru (-0.18 eV) and P (0.05 eV) are catalytic active sites for the hydrogen evolution reaction (HER), and the according charge redistribution of Ru is regulated by S and P with reverse electronegativity and electron-donor property to induce a synergistically enhanced reactivity toward the HER. This work provides a rational method to regulate the bonding and charge distribution of Ru-based electrocatalysts by reacting macromolecules with multielement of C/N/S/P with Ru.

14.
Small ; 16(32): e2001980, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32614517

RESUMEN

It is vitally essential to propose a novel, economical, and safe preparation method to design highly efficient electrocatalysts. Herein, phosphorus-doped iron nitride nanoparticles encapsulated by nitrogen-doped carbon nanosheets are grown directly on the iron foam substrate (P-Fe3 N@NC NSs/IF) by in situ deriving from Saccharomycetes cerevisiae (S. cerevisiae), where anion elements of C, N, and P all from S. cerevisiae replace the hazardous CH4 , NH3 , and H3 P. The diffusion pattern of N, P in S. cerevisiae and contact form between metal and S. cerevisiae observably affect the composition and phase of the product during high-temperature calcination. The obtained P-Fe3 N@NC NSs/IF demonstrates superior electrocatalytic performance for the hydrogen evolution reaction and oxygen evolution reaction, also satisfying durability. Theoretical calculation confirms that Fe sites of P-Fe3 N serve as the active center, and N sites and P doping regulate the hydrogen binding strength to enhance catalytic ability. Additionally, the two-electrode electrolyzer assembled by P-Fe3 N@NC NSs/IF as both anode and cathode electrodes needs only 1.61 V to reach 10 mA cm-2 for overall water splitting with a superb stability. The S. cerevisiae-based process presents a feasible approach for synthesis of nitrides, carbides, phosphides, and electrocatalytic applications.


Asunto(s)
Carbono , Nanopartículas , Hierro , Nitrógeno , Fósforo , Saccharomyces cerevisiae , Agua
15.
ACS Appl Mater Interfaces ; 12(2): 2362-2369, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31846290

RESUMEN

As a green, pollution-free, and renewable clean energy source, photocatalytic H2 production has attracted great attention. Here, epitaxial growth of pyramidal CdS-Cd nanoparticles on S-doped MoO2 nanosheets (CdS-Cd/S-MoO2) was prepared by one-step co-sublimation of CdS and MoO3. The photogenerated electrons of CdS as a photocatalyst are transferred to Cd and S-MoO2 as co-catalysts for H2 production, which is observed by surface photovoltage (SPV) under visible light irradiation. At last, the obtained CdS-Cd/S-MoO2 presented an efficient photocatalytic performance under the visible light (>420 nm) with a prominent H2 generation rate of as high as 24.98 µmol h-1 mg-1, which is 11 times higher than that of the CdS-Cd nanoparticles (2.26 µmol h-1 mg-1), and it is superior than that of the CdS (1.51 µmol h-1 mg-1).

16.
Nanomicro Lett ; 12(1): 131, 2020 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-34138146

RESUMEN

Hydrogen (H2) production is a latent feasibility of renewable clean energy. The industrial H2 production is obtained from reforming of natural gas, which consumes a large amount of nonrenewable energy and simultaneously produces greenhouse gas carbon dioxide. Electrochemical water splitting is a promising approach for the H2 production, which is sustainable and pollution-free. Therefore, developing efficient and economic technologies for electrochemical water splitting has been an important goal for researchers around the world. The utilization of green energy systems to reduce overall energy consumption is more important for H2 production. Harvesting and converting energy from the environment by different green energy systems for water splitting can efficiently decrease the external power consumption. A variety of green energy systems for efficient producing H2, such as two-electrode electrolysis of water, water splitting driven by photoelectrode devices, solar cells, thermoelectric devices, triboelectric nanogenerator, pyroelectric device or electrochemical water-gas shift device, have been developed recently. In this review, some notable progress made in the different green energy cells for water splitting is discussed in detail. We hoped this review can guide people to pay more attention to the development of green energy system to generate pollution-free H2 energy, which will realize the whole process of H2 production with low cost, pollution-free and energy sustainability conversion.

17.
iScience ; 19: 1090-1100, 2019 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-31527009

RESUMEN

The large-scale application of economically efficient electrocatalysts for hydrogen evolution reaction (HER) is limited in view of the high cost of polymer binders (Nafion) for immobilizing of powder catalysts. In this work, nitrogen-doped molybdenum carbide nanobelts (N-Mo2C NBs) with porous structure are synthesized through a direct pyrolysis process using the pre-prepared molybdenum oxide nanobelts (MoO3 NBs). Nanocellulose instead of Nafion-bonded N-Mo2C NBs (N-Mo2C@NCs) exhibits superior performance toward HER, because of excellent dispersibility and multiple exposed catalytically active sites. Furthermore, the conductive film composed of N-Mo2C NBs, graphene nanosheets, and nanocellulose (N-Mo2C/G@NCs) is fabricated by simple vacuum filtration, as flexible and editable electrode, which possesses excellent performance for scale HER applications. This work not only proposes the potential of nanocellulose to replace Nafion for binding powder catalysts, but also offers a facile strategy to prepare flexible and conductive films for a wide variety of nanomaterials.

18.
Adv Sci (Weinh) ; 6(18): 1901458, 2019 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-31559143

RESUMEN

Hydrogen (H2) production is a key step in solving the energy crisis in the future. Electrocatalytic water splitting suffers from sluggish anodic oxygen evolution reaction (OER) kinetics leading to low energy conversion efficiency. Herein, a strategy is presented that integrates anodic electrochemical flocculation with cathodic hydrogen production from water splitting in 0.5 m Na2SO4. Iron encapsulated in a nitrogen-doped carbon nanotubes array on iron foam (Fe@N-CNT/IF) is employed as an electrode for the hydrogen evolution reaction (HER), and the Fe@N-CNT/IF possesses superior HER activity requiring an overpotential of 525 mV to achieve 10 mA cm-2, which is close to that of 20 wt% Pt/C. Benefiting from the lower oxidation potential of iron (E°Fe/Fe2+, 0.44 V) than that of OER (E 0 OH-/O2, 1.23 V), the cell voltage for integrated electrochemical flocculation and H2 production is significantly reduced by 1.31 V relative to overall water splitting to achieve 20 mA cm-2. More important, the production of electrochemical flocculation can be applied to water purification, because of the excellent adsorption capacity. Finally, metal-carbon electrocatalysts are prepared again by pyrolysis of flocculation adsorbents containing toxic heavy metals and organics. This result provides a new direction for designing a heterogeneous electrolysis system for energy conversion and environmental treatment applications.

19.
ACS Nano ; 13(8): 9091-9099, 2019 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-31393706

RESUMEN

While pseudocapacitive electrodes have potential to store more energy than electrical double-layer capacitive electrodes, their rate capability is often limited by the sluggish kinetics of the Faradaic reactions or poor electronic and ionic conductivity. Unlike most transition-metal oxides, MoO2 is a very promising material for fast energy storage, attributed to its unusually high electronic and ionic conductivity; the one-dimensional tunnel is ideally suited for fast ionic transport. Here we report our findings in preparation and characterization of ultrathin MoO2 sheets with oriented tunnels as a pseudocapacitive electrode for fast charge storage/release. A composite electrode consisting of MoO2 and 5 wt % GO demonstrates a capacity of 1097 C g-1 at 2 mV s-1 and 390 C g-1 at 1000 mV s-1 while maintaining ∼80% of the initial capacity after 10,000 cycles at 50 mV s-1, due to minimal change in structural features of the MoO2 during charge/discharge, except a small volume change (∼14%), as revealed from operando Raman spectroscopy, X-ray analyses, and density functional theory calculations. Further, the volume change during cycling is highly reversible, implying high structural stability and long cycling life.

20.
Environ Pollut ; 247: 647-657, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30711820

RESUMEN

Development of low-cost cathode materials for Plant-Sediment Microbial Fuel Cells (P-SMFCs) has gained increasing interest, due to improved performance levels in terms of power and pollutant removal. A novel low cost three-dimensional cathode prepared by simple three-step strategy with growth of Co3O4 in-situ biofilm was successfully prepared. Different cathodes were applied to the six parallel P-SMFCs systems (reactor: R1-R6), such as graphite felt (GF), Pt/C, GF@Co3O4 (non-bonding Co3O4 nanowires on GF), GF@SG-Co3O4 (using argon as shielding gas (SG)). Its performances (R1, R2: control groups) were evaluated by electricity generation and Cr(VI) reduction at initial cadmium concentrations (4.97, 10.29 and 21.16 mg L-1). A significant Cr(VI) removal efficiency of 99.76%, maximum power density of 75.12 ±â€¯2.90 mW m-2 and Cr(VI) adsorption capacity of 1.67 mg g-1 were obtained at initial Cr(VI) concentration of 21.16 mg L-1 with non-bonding GF@Co3O4 and bio-GF@SG-Co3O4 as cathodes. This indicated that these two materials were better than others (GF, Pt/C and GF@Co3O4) as cathodes. Characterization analysis including scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Polarization curve, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) showed that high current generation Cr(VI) removal mainly attributed to transportation of plants, adsorption of bio-cathode, formation of a relatively high concentration region and abundant oxygen vacancies of GF@SG-Co3O4. The results show that P-SMFCs with GF@SG-Co3O4 cathode may be a potentially novel approach for remediating Cr(VI) contaminated waster or soil.


Asunto(s)
Fuentes de Energía Bioeléctrica , Cromo/química , Cobalto/química , Contaminantes Ambientales/química , Nanocables/química , Óxidos/química , Plantas , Adsorción , Biopelículas , Electricidad , Electrodos , Restauración y Remediación Ambiental , Sedimentos Geológicos/química , Grafito/química , Oxidación-Reducción , Oxígeno/química
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