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1.
Proc Natl Acad Sci U S A ; 119(3)2022 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-35017300

RESUMEN

The Fenton-like process catalyzed by metal-free materials presents one of the most promising strategies to deal with the ever-growing environmental pollution. However, to develop improved catalysts with adequate activity, complicated preparation/modification processes and harsh conditions are always needed. Herein, we proposed an ultrafast and facile strategy to convert various inefficient commercial nanocarbons into highly active catalysts by noncovalent functionalization with polyethylenimine (PEI). The modified catalysts could be in situ fabricated by direct addition of PEI aqueous solution into the nanocarbon suspensions within 30 s and without any tedious treatment. The unexpectedly high catalytic activity is even superior to that of the single-atom catalyst and could reach as high as 400 times higher than the pristine carbon material. Theoretical and experimental results reveal that PEI creates net negative charge via intermolecular charge transfer, rendering the catalyst higher persulfate activation efficiency.

2.
Nano Lett ; 24(5): 1776-1783, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38284760

RESUMEN

Donor-acceptor (D-A) copolymers doped with n-type dopants are widely sought after for their potential in organic thermoelectric devices. However, the existing structural disorder significantly hampers their charge transport and thermoelectric performance. In this Letter, we propose a mechanism to mitigate this disorder through side chain engineering. Utilizing molecular dynamics simulations, we demonstrate that strong Coulomb interactions between counterions and charged polymer backbones induce a transition in the stacking arrangement of the polymer backbones from a slipped to a vertical configuration. However, the presence of side chain steric hindrance impedes the formation of closely packed and ordered vertical stacking arrangements, resulting in greater distances between adjacent backbones and a higher level of structural disorder in the doped films. Therefore, we propose minimizing side chain steric hindrance to enhance the structural order in doped films. Our findings provide essential insights for advancing high-performance thermoelectric polymers.

3.
Nano Lett ; 24(39): 12140-12147, 2024 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-39119948

RESUMEN

N-Doped carbon sheets based on edge engineering provide more opportunities for improving oxygen reduction reaction (ORR) active sites. However, with regard to the correlation between porous structural configurations and performances, it remains underexplored. Herein, a silica-assisted localized etching method was employed to create two-dimensional mesoporous carbon materials with customizable pore structures, abundant edge sites, and nitrogen functionalities. The mesoporous carbon exhibited superior electrocatalytic performance for the ORR compared to that of a 20 wt % Pt/C catalyst, achieving a half-wave potential of 0.88 V versus RHE, situating them in the leading level of the reported carbon electrocatalysts. Experimental data suggest that the edge graphitic nitrogen sites played a crucial role in the ORR process. The three-dimensional interconnected pores provided a high density of active sites for the ORR and facilitated the efficient transport of electrons. These unique properties make the carbon sheets a promising candidate for highly efficient air cathodes in rechargeable Zn-air batteries.

4.
Small ; 20(24): e2310587, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38546418

RESUMEN

The process of N-doping is frequently employed to enhance the properties of carbon quantum dots. However, the precise requirements for nitrogen precursors in producing high-quality N-doped carbon quantum dots (NCQDs) remain undefined. This research systematically examines the influence of various nitrogen dopants on the morphology, optical features, and band structure of NCQDs. The dots are synthesized using an efficient, eco- friendly, and rapid continuous hydrothermal flow technique. This method offers unparalleled control over synthesis and doping, while also eliminating convention-related issues. Citric acid is used as the carbon source, and urea, trizma base, beta-alanine, L-arginine, and EDTA are used as nitrogen sources. Notably, urea and trizma produced NCQDs with excitation-independent fluorescence, high quantum yields (up to 40%), and uniform dots with narrow particle size distributions. Density functional theory (DFT) and time-dependent DFT modelling established that defects and substituents within the graphitic structure have a more significant impact on the NCQDs' electronic structure than nitrogen-containing functional groups. Importantly, for the first time, this work demonstrates that the conventional approach of modelling single-layer structures is insufficient, but two layers suffice for replicating experimental data. This study, therefore, provides essential guidance on the selection of nitrogen precursors for NCQD customization for diverse applications.

5.
Small ; 20(8): e2308045, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37828632

RESUMEN

Nitrogen (N) doping of graphene with a three-dimensional (3D) porous structure, high flexibility, and low cost exhibits potential for developing metal-air batteries to power electric/electronic devices. The optimization of N-doping into graphene and the design of interconnected and monolithic graphene-based 3D porous structures are crucial for mass/ion diffusion and the final oxygen reduction reaction (ORR)/battery performance. Aqueous-type and all-solid-state primary Mg-air batteries using N-doped nanoporous graphene as air cathodes are assembled. N-doped nanoporous graphene with 50-150 nm pores and ≈99% porosity is found to exhibit a Pt-comparable ORR performance, along with satisfactory durability in both neutral and alkaline media. Remarkably, the all-solid-state battery exhibits a peak power density of 72.1 mW cm-2 ; this value is higher than that of a battery using Pt/carbon cathodes (54.3 mW cm-2 ) owing to the enhanced catalytic activity induced by N-doping and rapid air breathing in the 3D porous structure. Additionally, the all-solid-state battery demonstrates better performances than the aqueous-type battery owing to slow corrosion of the Mg anode by solid electrolytes. This study sheds light on the design of free-standing and catalytically active 3D nanoporous graphene that enhances the performance of both Mg-air batteries and various carbon-neutral-technologies using neutral electrolytes.

6.
Small ; : e2404120, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39210636

RESUMEN

Charge-transfer complex formation within the pores of porous polymers is an efficient way to tune their electronical properties. Introduction of electron accepting guests to the electron donating hosts to conduct their p-doping is intensively studied in this context. However, the vice versa scenario, n-doping by treating the electron deficient (i.e., n-type) porous polymers with electron donating dopants, is rare. In this work, synthesis of an n-type phenazine based conjugated microporous polymer and its exposure to strong electron donating tetrathiafulvalene (TTF) dopants are presented. The fundamental physical characterizations (e.g., elemental analysis, gas sorption) showed that the vacuum impregnation technique is a good approach to load the guest molecules inside the pores. Moreover, the formation of charge-transfer complexes between the phenazine building blocks of the polymeric network and TTF dopants are confirmed via spectral techniques such Fourier transform infra-red, UV-vis, steady-state/time-resolved photoluminescence, and transient absorbance spectroscopies. Effect of the doping to the electronical properties is monitored by employing photoelectrochemical measurements, which showed lower charge-transfer resistivity and nearly doubled photocurrents after the doping. The study is, therefore, an important advancement for the applicability of (n-type) porous polymeric materials in the field of photo(electro)catalysis and organic electronics.

7.
Small ; 20(37): e2401103, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38709231

RESUMEN

The unsaturated amides are traditionally synthesized by acylation of carboxylic acids or hydration of nitrile compounds but are rarely investigated by hydroaminocarbonylation of alkynes using heterogeneous single-metal-site catalysts (HSMSCs). Herein, single-Pd-site catalysts supported on N-doping carbon (NC) with different nitrogen dimensions inherited from corresponding metal-organic-framework precursors are successfully synthesized. 2D NC-supported single-Pd-site (Pd1/NC-2D) exhibited the best performance with near 100% selectivity and 76% yield of acrylamide for acetylene hydroaminocarbonylation with better stability, superior to those of Pd1/NC-3D, single-metal-site/nanoparticle coexisting catalyst, and nanoparticle catalyst. The coordination environment and molecular evolution of the single-Pd-site during the process of acetylene hydroaminocarbonylation on Pd1/NC-2D are detailly illuminated by various characterizations and density functional theoretical calculations (DFT). DFT also showed the energy barrier of rate-determining step on Pd1/NC-2D is lower than that of Pd1/NC-3D. Furthermore, Pd1/NC-2D catalyst illustrated the general applicability of the hydroaminocarbonylation for various alkynes.

8.
Small ; : e2403413, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38934357

RESUMEN

Tin-halide perovskites (THP) are emerging materials for photovoltaics with optoelectronic properties potentially rivaling lead-based analoges. Their efficiencies in solar cells are, however, severely limited by the high sensitivity of tin to oxygen and the heavy p-doping natively present in the material. While the effects of oxygen can be mitigated by using reducing agents upon the synthesis and by encapsulating the device, the native p-doping caused by the high density of acceptor defects remains a challenge to be further addressed for prolonging carrier lifetimes and, consequently, device efficiency. In this work, potential compositional engineering strategies aimed at reducing the p-doping of this class of materials and increasing their efficiency in solar cells are investigated. Based on density functional theory simulations it is demonstrated that THP doping with d1s2 trivalent ions effectively decreases the hole background density and the density of the deep defects responsible for the non-radiative recombination in these materials. This effect is enhanced by alloying iodide with small fractions of bromide, up to 33%. Higher bromide fractions, instead, are detrimental due to the increased non-radiative recombination. These results may provide useful guidelines to experimentalists for improving the optoelectronic quality of THPs and consequently of the ensuing devices.

9.
Small ; 20(33): e2310467, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38552223

RESUMEN

Electroreduction of nitrate to ammonia provides an interesting pathway for wastewater treatment and valorization. Cu-based catalysts are active for the conversion of NO3 - to NO2 - but suffer from an inefficient hydrogenation process of NO2 -. Herein, CuxO/N-doped graphdiyne (CuxO/N-GDY) with pyridine N configuration are in situ prepared in one pot. Benefiting from the synergistic effect of pyridinic N in GDY and CuxO, the prepared CuxO/N-GDY tested in a commercial H-cell achieved a faradaic efficiency of 85% toward NH3 at -0.5 V versus RHE with a production rate of 340 µmol h-1 mgcat -1 in 0.1 M KNO3. When integrating the CuxO/N-GDY in an anion exchange membrane flow electrolyzer, a maximum Faradaic efficiency of 89% is achieved at a voltage of 2.3 V and the production rate is 1680 µmol h-1 mgcat -1 at 3.3 V in 0.1 M KNO3 at room temperature. Operation at 40 °C further promoted the overall reaction kinetics of NO3 - to NH3, but penalized its selectivity with respect to hydrogen evolution reaction. The high selectivity and production rate in this device configuration demonstrate its potential for industrial application.

10.
Nanotechnology ; 35(28)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38579687

RESUMEN

Oxygen vacancies and heteroatom doping play important role in oxygen reduction activity of metal oxides. Developing efficient modification method is one of the key issues in catalysts research. Room temperature plasma treatment, with the advantages of mild working conditions, no emissions and high efficiency, is a new catalyst modification method developed in recent years. In this work, hydrothermal synthesizedα-MnO2nanorods are treated in NH3plasma at room temperature. In the reducing atmosphere, oxygen vacancies and N doping are achieved simultaneously on the surface. The NH3plasma etched MnO2demonstrate a significant enhanced oxygen reduction activity with half-wave potential of 0.84 V, limiting current density of 6.32 mA cm-2and transferred electrons number of 3.9. The Mg-air battery with N-MnO2display a maximum power density of 76.3 mW cm-2as well as stable discharge performance. This work provides new ideas for preparing efficient and cost-effective method to boost the catalysts activity.

11.
J Fluoresc ; 34(1): 213-226, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37191828

RESUMEN

Carbon quantum dots (CQDs) are a new type of fluorescent QDs that consists mainly of carbon atoms. In this research, CQDs were synthesized through harsh oxidizing conditions applied on carbon black and subsequent N-doping using hexamethylenetetramine (Hexamine) and polyethyleneimine (PEI). The synthesized CQDs were characterized using FTIR, AFM, UV-Visible spectroscopy, photoluminescence (PL) spectroscopy, and fluorescence imaging respectively. The AFM images showed that the dots are in the range of 2-8 nm. N-doping of the CQDs increased the PL intensity. The PL enhancement for the CQDs that were N-doped with PEI was higher compared to those N-doped with hexamine. The shift in PL by changing the excitation wavelength has been attributed to the nano-size of the CQDs, functional groups, defect traps, and quantum confinement effect. The in vitro fluorescence imaging revealed that N-doped CQDs can internalize into the cells and be used for fluorescent cell imaging.


Asunto(s)
Puntos Cuánticos , Hollín , Puntos Cuánticos/química , Carbono/química , Metenamina
12.
Environ Res ; 260: 119664, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39048069

RESUMEN

The preparation of nitrogen-doped TiO2 (i.e., N-TiO2) catalysts is a highly effective option to improve the photocatalytic activity of TiO2. Nonetheless, relatively little is known about the effects of dopant precursors selected for their preparation with regard to the photocatalytic efficacy. In this study, three types of dopants are selected and used as N sources (urea (U), melamine (M), and aqueous ammonia (A)) for N-TiO2 samples with the name codes of NTU, NTM, and NTA, respectively. The photocatalytic efficacy of these N-TiO2 samples is examined against toluene in a packed bed flow reactor. Under optimal conditions (e.g., relative humidity (RH) = 20% and gas hourly space velocity (GHSV) = 1698 h-1), the superiority of NTA is evident over others with a quantum efficiency (QE) of 7.03 × 10-4 molecules photon-1, a space time yield (STY) of 1.38 × 10-4 molecules photon-1 mg-1, and a specific clean air delivery rate (SCADR) of 1148.8 L g-1 h-1. The analysis based on in-situ diffuse reflectance infrared Fourier transform spectroscopy and gas chromatography-mass spectrometry confirms the formation of several intermediates such as benzyl alcohol, benzaldehyde, benzoic acid, and alkane species through ring opening reactions. In addition, the prepared NTA photocatalyst exhibits the highest toluene photocatalytic degradation efficiency among all TiO2-based catalysts surveyed to date. Overall, this study offers as a valuable guideline for the development of advanced TiO2 catalytic systems (such as N-TiO2) for the treatment of aromatic hydrocarbons in indoor air.


Asunto(s)
Nitrógeno , Titanio , Tolueno , Titanio/química , Tolueno/química , Catálisis , Nitrógeno/química , Contaminantes Atmosféricos/química , Contaminantes Atmosféricos/análisis , Triazinas/química , Procesos Fotoquímicos , Fotólisis
13.
Environ Res ; 260: 119579, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-38986803

RESUMEN

In this work, a novel nitrogen-doped biochar bentonite composite was synthesized by a single-pot co-pyrolysis method. Batch studies were conducted to evaluate the performance of the developed composite in eliminating synthetic dyes from the aqueous matrix. Energy dispersive X-ray spectroscopy analysis and field emission scanning electron microscopy imaging confirmed the N doping and bentonite impregnation into biochar. X-ray photoelectron spectroscopy analysis revealed that the N atoms were doped interstitially into the carbon matrix of biochar in the form of pyridinic and pyrrolic nitrogen. Simultaneous heteroatom doping and bentonite impregnation reduced the specific surface area to 41.721 m2 g-1 but improved the adsorption capacity of biochar for dye adsorption. Further experimental studies depicted that simultaneous bentonite impregnation and N doping into the biochar matrix is beneficial for direct blue-6 (DB-6) and methylene blue (MB) removal and maximum adsorption capacities of 53.17 mg. g-1 and 41.33 mg. g-1 were obtained for MB and DB-6, respectively, at varying conditions. Adsorption energetics of the dyes with the developed composite portrayed the spontaneity of the process through negative ΔG values. The Langmuir and Freundlich isotherm models fitted the best for MB and DB-6 adsorption. The monolayer adsorption capacity and favourability factor for MB and DB-6 adsorption were calculated to be 54.15 mg. g-1 and 0.217, respectively from the best-fitted isotherms. Based on density functional theory calculations and spectroscopic studies, major interactions governing the adsorption were predicted to be charge-based interactions, π-π interactions, H-bonding, and Lewis acid-base interactions.


Asunto(s)
Carbón Orgánico , Colorantes , Contaminantes Químicos del Agua , Carbón Orgánico/química , Colorantes/química , Adsorción , Contaminantes Químicos del Agua/química , Modelos Químicos , Silicatos/química , Silicatos de Aluminio
14.
J Environ Manage ; 357: 120823, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38583380

RESUMEN

Fe(II) regeneration plays a crucial role in the electro-Fenton process, significantly influencing the rate of ·OH formation. In this study, a method is proposed to improve Fe(II) regeneration through N-doping aimed at enhancing the adsorption capacity of the activated carbon cathode for Fe(III). N-doping not only enriched the pore structure on the surface of activated carbon, providing numerous adsorption sites, but also significantly increased the adsorption energy for Fe(III). Among the types of nitrogen introduced, pyridine-N exhibited the most substantial enhancement effect, followed by pyrrole-N, while graphite-N showed a certain degree of inhibition. Furthermore, N-doping facilitated the adsorption of all forms of Fe(III) by activated carbon. The adsorption and electrosorption rates of the NAC-900 electrode for Fe(III) were 30.33% and 42.36%, respectively. Such modification markedly enhanced the Fe3+/Fe2+ cycle within the electro-Fenton system. The NAC-900 system demonstrated an impressive phenol degradation efficiency of 93.67%, alongside the lowest electricity consumption attributed to the effective "adsorption-reduction" synergy for Fe(III) on the NAC-900 electrode. Compared to the AC cathode electro-Fenton system, the degradation efficiency of the NAC-900 cathode electro-Fenton system at pH = levels ranging from 3 to 5 exceeded 90%; thus, extending the pH applicability of the electro-Fenton process. The degradation efficiency of phenol using the NAC-900 cathode electro-Fenton system in various water matrices approached 90%, indicating robust performance in real wastewater treatment scenarios. This research elucidates the impact of cathodic Fe(III) adsorption on Fe(II) regeneration within the electro-Fenton system, and clarifies the influence of different N- doping types on the cathodic adsorption of Fe(III).


Asunto(s)
Compuestos Férricos , Contaminantes Químicos del Agua , Adsorción , Contaminantes Químicos del Agua/química , Carbón Orgánico/química , Conservación de los Recursos Energéticos , Oxidación-Reducción , Electrodos , Fenol , Compuestos Ferrosos , Peróxido de Hidrógeno/química
15.
J Environ Sci (China) ; 143: 12-22, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38644010

RESUMEN

Selective catalytic NH3-to-N2 oxidation (NH3-SCO) is highly promising for abating NH3 emissions slipped from stationary flue gas after-treatment devices. Its practical application, however, is limited by the non-availability of low-cost catalysts with high activity and N2 selectivity. Here, using defect-rich nitrogen-doped carbon nanotubes (NCNT-AW) as the support, we developed a highly active and durable copper-based NH3-SCO catalyst with a high abundance of cuprous (Cu+) sites. The obtained Cu/NCNT-AW catalyst demonstrated outstanding activity with a T50 (i.e. the temperature to reach 50% NH3 conversion) of 174°C in the NH3-SCO reaction, which outperformed not only the Cu catalyst supported on N-free O-functionalized CNTs (OCNTs) or NCNT with less surface defects, but also those most active Cu catalysts in open literature. Reaction kinetics measurements and temperature-programmed surface reactions using NH3 as a probe molecule revealed that the NH3-SCO reaction on Cu/NCNT-AW follows an internal selective catalytic reaction (i-SCR) route involving nitric oxide (NO) as a key intermediate. According to mechanistic investigations by X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray absorption spectroscopy, the superior NH3-SCO performance of Cu/NCNT-AW originated from a synergy of surface defects and N-dopants. Specifically, surface defects promoted the anchoring of CuO nanoparticles on N-containing sites and, thereby, enabled efficient electron transfer from N to CuO, increasing significantly the fraction of SCR-active Cu+ sites in the catalyst. This study puts forward a new idea for manipulating and utilizing the interplay of defects and N-dopants on carbon surfaces to fabricate Cu+-rich Cu catalysts for efficient abatement of slip NH3 emissions via selective oxidation.


Asunto(s)
Amoníaco , Cobre , Oxidación-Reducción , Cobre/química , Amoníaco/química , Catálisis , Nanotubos de Carbono/química , Contaminantes Atmosféricos/química , Temperatura , Modelos Químicos
16.
Angew Chem Int Ed Engl ; 63(33): e202407273, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-38770935

RESUMEN

A new approach to control the n-doping reaction of organic semiconductors is reported using surface-functionalized gold nanoparticles (f-AuNPs) with alkylthiols acting as the catalyst only upon mild thermal activation. To demonstrate the versatility of this methodology, the reaction of the n-type dopant precursor N-DMBI-H with several molecular and polymeric semiconductors at different temperatures with/without f-AuNPs, vis-à-vis the unfunctionalized catalyst AuNPs, was investigated by spectroscopic, morphological, charge transport, and kinetic measurements as well as, computationally, the thermodynamic of catalyst activation. The combined experimental and theoretical data demonstrate that while f-AuNPs is inactive at room temperature both in solution and in the solid state, catalyst activation occurs rapidly at mild temperatures (~70 °C) and the doping reaction completes in few seconds affording large electrical conductivities (~10-140 S cm-1). The implementation of this methodology enables the use of semiconductor+dopant+catalyst solutions and will broaden the use of the corresponding n-doped films in opto-electronic devices such as thin-film transistors, electrochemical transistors, solar cells, and thermoelectrics well as guide the design of new catalysts.

17.
Small ; 19(39): e2302475, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37231568

RESUMEN

Developing an inexpensive bifunctional electrocatalyst for overall water splitting is critical for acquiring scalable green hydrogen and thereby realizing carbon neutralization. Herein, an "all-in-one" method is developed for the fabrication of highly N-doped binary FeCo-phosphides (N-FeCoP) with hierarchical superstructure, this delicately designed synthesis route allows the following merits for benefiting water splitting electrocatalysis in alkaline, including high N/defect-doping for mediating the surface property of the as-made N-FeCoP, binary Fe and Co components exhibiting strong coupling interaction, and 3D hierarchical superstructure for shortening diffusion length and thereby improving reaction kinetics. Electrochemical measurements reveal that the N-FeCoP sample exhibits very low overpotentials for initiating the hydrogen and oxygen evolution reactions. Remarkably, overall water splitting can be promoted on N-FeCoP using a commercial primary Zn-MnO2 battery. The developed synthesis strategy may potentially inspire the preparation of other N-doped metal-based nanostructures for broad electrocatalysis.

18.
Small ; 19(28): e2207196, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37026435

RESUMEN

The exploring of economical, high-efficiency, and stable bifunctional catalysts for hydrogen evolution and oxygen evolution reactions (HER/OER) is highly imperative for the development of electrolytic water. Herein, a 3D cross-linked carbon nanotube supported oxygen vacancy (Vo )-rich N-NiMoO4 /Ni heterostructure bifunctional water splitting catalyst (N-NiMoO4 /Ni/CNTs) is synthesized by hydrothermal-H2 calcination method. Physical characterization confirms that Vo -rich N-NiMoO4 /Ni nanoparticles with an average size of ≈19 nm are secondary aggregated on CNTs that form a hierarchical porous structure. The formation of Ni and NiMoO4 heterojunctions modify the electronic structure of N-NiMoO4 /Ni/CNTs. Benefiting from these properties, N-NiMoO4 /Ni/CNTs drives an impressive HER overpotential of only 46 mV and OER overpotential of 330 mV at 10 mA cm-2 , which also shows exceptional cycling stability, respectively. Furthermore, the as-assembled N-NiMoO4 /Ni/CNTs||N-NiMoO4 /Ni/CNTs electrolyzer reaches a cell voltage of 1.64 V at 10 mA cm-2 in alkaline solution. Operando Raman analysis reveals that surface reconstruction is essential for the improved catalytic activity. Density functional theory (DFT) calculations further demonstrate that the enhanced HER/OER performance should be attributed to the synergistic effect of Vo and heteostructure that improve the conductivity of N-NiMoO4 /Ni/CNTs and facilitatethe desorption of reaction intermediates.

19.
Environ Res ; 229: 115998, 2023 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-37127103

RESUMEN

As a recycling use of waste activated sludge (WAS), we used high-temperature pyrolysis of WAS to support bimetallic Fe-Mn with nitrogen (N) co-doping (FeMn@N-S), a customized composite catalyst that activates peroxysulphate (PS) for the breakdown of tetracycline (TC). First, the performance of TC degradation was evaluated and optimized under different N doping, pH, catalyst dosages, PS dosages, and contaminant concentrations. Activating PS with FeMn@N-S caused the degradation of 91% of the TC in 120 min. Next, characterization of FeMn@N-S by XRD, XPS and FT-IR analysis highlights N doping is beneficial to take shape more active sites and reduces the loss of Fe and Mn during the degradation reaction. As expected, the presence of Fe-Mn bimetallic on the catalyst surface increases the rate of electron transfer, promoting the redox cycle of the catalyst. Other functional groups on the catalyst surface, such as oxygen-containing groups, accelerated the electron transfer during PS activation. Free radical quenching and ESR analysis suggest that the main contributor to TC degradation is surface-bound SO4•-, along with the presence of single linear oxygen (1O2) oxidation pathway. Finally, the FeMn@N-S composite catalyst exhibits excellent pH suitability and reusability, indicating a solid practicality of this catalyst in PS-based removal of antibiotics from wastewater.


Asunto(s)
Aguas del Alcantarillado , Contaminantes Químicos del Agua , Nitrógeno/análisis , Espectroscopía Infrarroja por Transformada de Fourier , Tetraciclina/química , Antibacterianos , Oxígeno/análisis , Contaminantes Químicos del Agua/análisis
20.
J Environ Manage ; 344: 118611, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37453301

RESUMEN

Polychlorinated dibenzo-p-dioxin/furans (PCDD/F) have a great threat to the environment and human health, resulting in controlling PCDD/F emissions to regulation far important for emission source. Considering 2,3,4,7,8-pentachlorodibenzo-p-furan (PeCDF) identified as the most contributor to international toxic equivalent, 2,3,4,7,8-PeCDF can be considered as the target molecule for the adsorption of PCDD/F emission from industries. With the aim to in-depth elucidate how different types of nitrogen (N) species enhance 2,3,4,7,8-PeCDF on the biochar and guide the specific carbon materials design for industries, systematic computational investigations by density functional theory calculations were conducted. The results indicate pristine biochar intrinsically interacts with 2,3,4,7,8-PeCDF by π-π electron donor and acceptor (EDA) interaction, six-membered carbon rings of PeCDF parallel to the biochar surface as the strongest adsorption configuration. Moreover, by comparison of adsorption energy (-150.16 kJ mol-1) and interaction distance (3.593 Å) of pristine biochar, environment friendly N doping can enhance the adsorption of 2,3,4,7,8-PeCDF on biochar. Compared with graphitic N doping and pyridinic N doping, pyrrolic N doping biochar presents the strongest interaction toward 2,3,4,7,8-PeCDF molecule due to the highest adsorption energy (-155.56 kJ mol-1) and shortest interaction distance (3.532 Å). Specially, the enhancing adsorption of PeCDF over N doped biochar attributes to the enhancing π-π electron EDA interaction and electrostatic interaction. In addition, the effect of N doping species on PeCDF adsorbed on the biochar is more than that of N doping content. Specially, the adsorption capacity of N doping biochar for PCDD/F can be improved by adding pyrrolic N group most efficiently. Furthermore, pyrrolic N and pyridinic N doping result in the entropy increase, and electrons transform from pyrrolic N and pyridinic N doped biochar to 2,3,4,7,8-PeCDF molecule. A complete understanding of the research would supply crucial information for applying N-doped biochar to effectively remove PCDD/F for industries.


Asunto(s)
Nitrógeno , Dibenzodioxinas Policloradas , Humanos , Adsorción , Carbono
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