Highly stable carbon-coated nZVI composite Fe0@RF-C for efficient degradation of emerging contaminants

Nanoscale zerovalent iron(nZVI)has garnered significant attention as an efficient advanced oxidation activator,but its practical application is hindered by aggregation and oxidation.Coating nZVI with carbon can effectively addresses these issues.A simple and scalable production method for carbon-coated nZVI composite is highly desirable.The anti-oxidation and catalytic performance of carbon-coated nZVI composite merit in-depth research.In this study,a highly stable carbon-coated core-shell nZVI composite(Fe0@RF-C)was successfully prepared using a simple method combining phenolic resin embedding and carbothermal reduction.Fe0@RF-C was employed as a heterogeneous persulfate(PS)activator for degrading 2,4-dihydroxybenzophenone(BP-1),an emerging contaminant.Compared to commercial nZVI,Fe0@RF-C exhibited superior PS activation performance and oxidation resistance.Nearly 95%of BP-1 was removed within 10 min in the Fe0@RF-C/PS system.The carbon layer promotes the enrichment of BP-1 and accelerates its degradation through singlet oxygen oxidation and direct electron transfer processes.This study provides a straightforward approach for designing highly stable carbon-coated nZVI composite and elucidates the enhanced catalytic performance mechanism by carbon layers.

Performance of carbon-coated nano-ZnO prepared by carbonizing gel precursor as anodic material for secondary alkaline Zn batteries

Although carbon coating can improve the cycle life of anode for alkaline Zn batteries, the specific capacity reported is still lower compared with nanosized ZnO. Herein, carbon-coated nanosized ZnO(nano-ZnO@C) was synthesized by one-step heat treatment from a gel precursor in N2. Commercial ZnO and homemade ZnO prepared similarly in air atmosphere were studied for comparison. Structure analysis displayed that both nano-ZnO@C and homemade ZnO had a porous hierarchical agglomerated architecture produced from primary nanoparticles with a diameter of approximately 100 nm as building blocks. Electrochemical performance measurements showed that nano-ZnO@C displayed the highest electrochemical activity, the lowest electrode resistance, the highest discharge capacity(622 m A·h/g), and the best cyclic stability. These properties were due to the combination of nanosized ZnO and the physical capping of carbon, which maintained the high utilization efficiency of nano-ZnO, and simultaneously prevented dendrite growth and densification of the anode.

Carbon-coated magnetic particles increase tissue temperatures after laser irradiation

Purpose:This work focused on the investigation the hyperthermia performance of the carboncoated magnetic particles(CCMPs)in laser-induced hyperthermia.Materials and methods:We prepared CCMPs using the organic carbonization method,and then characterized them with transmission electron microscopy(TEM),ultraviolet-visible(UV-Vis)spectrophotometry,vibrating sample magnetometer(VSM)and X-ray di®raction(XRD).In order to evaluate their performance in hyperthermia,the CCMPs were tested in laser-induced thermal therapy(LITT)experiments,in which we employed a fully distributedfiber Bragg grating(FBG)sensor to profile the tissue's dynamic temperature change under laser irradiation in real time.Results:The sizes of prepared CCMPs were about several micrometers,and the LITT results show that the tissue injected with the CCMPs absorbed more laser energy,and its temperature increased faster than the contrast tissue without CCMPs.Conclusions:The CCMPs may be of great help in hyperthermia applications.

PEG-combined liquid phase synthesis and electrochemical properties of carbon-coated Li_3V_2(PO_4)_3

The carbon-coated monoclinic Li3V2(PO4)3(LVP) cathode materials were successfully synthesized by liquid phase method using PEG as reducing agent and carbon source. The effects of relative molecular mass of PEG on the properties of Li3V2(PO4)3/C were evaluated by X-ray diffraction(XRD), scanning electron microscope(SEM) and electrochemical performance tests. The SEM images show that smaller size particles are obtained by adding larger and smaller PEGs. The electrochemical cycling of Li3V2(PO4)3/C prepared by both PEG200 and PEG20 k has a high initial discharge capacity of 131.1 mA·h/g at 0.1C during 3.0-4.2 V, and delivers a reversible discharge capacity of 123.6 m A·h/g over 30 cycles, which is better than that of other samples. The improvement in electrochemical performance is caused by its improved lithium ion diffusion coefficient for the macroporous morphology, which is verified by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).

Carbon-coated Li3VO4 with optimized structure as high capacity anode material for lithium-ion capacitors

Due to the high capacity,moderate voltage platform,and stable structure,Li3VO4(LVO) has attracted close attention as feasible anode material for lithium-ion capacitor.However,the intrinsic low electronic conductivity and sluggish kinetics of the Li+ insertion process severely impede its practical application in lithium-ion capacitors(LICs).Herein,a carbon-coated Li3VO4(LVO/C) hierarchical structure was prepared by a facial one-step solid-state method.The synthesized LVO/C composite delivers an impressive capacity of 435 mAh/g at 0.07 A/g,remarkable rate capability,and nearly 100% capacity retention after 500 cycles at 0.5 A/g.The superior electrochemical properties of LVO/C composite materials are attributed to the improved conductivity of electron and stable carbon/LVO composite structures.Besides,the LIC device based on activated carbon(AC) cathode and optimal LVO/C as anode reveals a maximum energy density of 110 Wh/kg and long-term cycle life.These results provide a potential way for assembling the advanced hybrid lithium-ion capacitors.

Synthesis of carbon-coated Li4Ti5O12 and its electrochemical performance as anode material for lithium-ion battery

Carbon-coated Li4Ti5O12 sample was synthesized by a sol-gel method. The Li4Tis012 powders were obtained by calcinations of the gels at 750, 800, 850, 900 ℃ at N2 atmosphere. The structure, morphology and electrochemical properties of the materials were characterized by SEM, XRD and charge and discharge. The final product sintered at 850℃ demonstrates excellent performance with a specific capacity of 163.5 mAh/g after 100 cycles at 1C. Furthermore, the discharge specific capacity of the sample can retain 80 mAh/g at 10℃.

One-step synthesis of carbon-coated monocrystal molybdenum oxides nanocomposite as high-capacity anode materials for lithiumion batteries

Benefitting from higher specific capacities,acceptable cost,nontoxicity and unique crystal structures,the molybdenum oxides have been studied as the anode materials for lithium ion batteries(LIBs).Herein,a direct current(DC)arc-discharge plasma technique has been developed to in-situ synthesize carboncoated monocrystal molybdenum oxides((MoO3NRs/MoO2NPs)@C)nanocomposites,using coarse MoO_(3) bulk as the raw material and methane(CH4)gas as the carbon source.It is indicated that crystallographic traits of MoO_(3) and MoO2 nuclei give rise to an anisotropic growth of monocrystal MoO3 nanorods(NRs)along<100>direction and an isotropic growth of monocrystal MoO_(2) nanoparticles(NPs).The carbon shells on MoO3/MoO2 nanostructures are generated from the absorption of carbon atoms in surrounding atmosphere or the release of supersaturated carbon atoms in MoeOeC solid solution.Unique constitution and pseudo-capacitive behavior of(MoO3NRs/MoO2NPs)@C bring merits to excellent cycling performance and rate capability,i.e.a remarkable specific capacity of 840 mAh·g^(-1) after 100 cycles at a current density of 0.1 Ag^(-1) and a retained capacity of 210 mAh·g^(-1) at 6.4 A g^(-1).This work has offered a simple and efficient approach to fabricate the carbon-coated molybdenum oxides nanostructures for promising anode materials of LIBs。

Carbon-coated Ni-Co alloy catalysts:preparation and performance for in-situ aqueous phase hydrodeoxygenation of methyl palmitate to hydrocarbons using methanol as the hydrogen donor

Carbon-coated Ni,Co and Ni-Co alloy catalysts were prepared by the carbonization of the metal doped resorcinol-formaldehyde resins synthesized by the one-pot extended Stöber method.It was found that the introduction of Co remarkably reduced the carbon microsphere size.The metallic Ni,Co,and Ni-Co alloy particles(mainly 10-12 nm)were uniformly distributed in carbon microspheres.A charge transfer from Ni to Co appeared in the Ni-Co alloy.Compared with those of metallic Ni and Co,the d-band center of the Ni-Co alloy shifted away from and toward the Fermi level,respectively.In the in-situ aqueous phase hydrodeoxygenation of methyl palmitate with methanol as the hydrogen donor at 330℃,the decarbonylation/decarboxylation pathway dominated on all catalysts.The Ni-Co@C catalysts gave higher activity than the Ni@C and Co@C catalysts,and the yields of n-pentadecane and n-C6-n-C16 reached 71.6%and 92.6%,respectively.The excellent performance of Ni-Co@C is attributed to the electronic interactions between Ni and Co and the small carbon microspheres.Due to the confinement effect of carbon,the metal particles showed high resistance to sintering under harsh hydrothermal conditions.Catalyst deactivation is due to the carbonaceous deposition,and the regeneration with CO_(2) recovered the catalyst reactivity.

Carbon-coated lithium titanate: effect of carbon precursor addition processes on the electrochemical performance

In this paper,two carbon-coated lithium titanate(LTO-C1 and LTO-C2)composites were synthesized using the ball-milling-assisted calcination method with different carbon precursor addition processes.The physical and electrochemical properties of the as-synthesized negative electrode materials were characterized to investigate the effects of two carbon-coated LTO synthesis processes on the electrochemical performance of LTO.The results show that the LTO-C2 synthesized by using Li2CO3 and TiO2 as the raw materials and sucrose as the carbon source in a one-pot method has less polarization during lithium insertion and extraction,minimal charge transfer impedance value and the best electrochemical performance among all samples.At the current density of 300 mA·h·g^(-1),the LTO-C2 composite delivers a charge capacity of 126.9 mA·h·g^(-1),and the reversible capacity after 300 cycles exceeds 121.3 mA·h·g^(-1) in the voltage range of 1.0–3.0 V.Furthermore,the electrochemical impedance spectra show that LTO-C2 has higher electronic conductivity and lithium diffusion coefficient,which indicates the advantages in electrode kinetics over LTO and LTO-C1.The results clarify the best electrochemical properties of the carbon-coated LTO-C2 composite prepared by the one-pot method.

Theoretical calculation and experiment of microwave electromagnetic property of Ni(C) nanocapsules

With the combination of the dielectric loss of the carbon layer with the magnetic loss of the ferromagnetic metal core, carbon-coated nickel （Ni（C）） nanoparticles are expected to be the promising microwave absorbers. Microwave electromag- netic parameters and reflection loss in a frequency range of 2 GHz-18 GHz for paraffin-Ni（C） composites are investigated. The values of relative complex permittivity and permeability, the dielectric and magnetic loss tangent of paraffin-Ni（C） com- posites are measured, respectively, when the weight ratios of Ni（C） nanoparticles are equal to 10 wt%, 40 wt%, 50 wt%, 70 wt%, and 80 wt% in paraffin-Ni（C） composites. The results reveal that Ni（C） nanoparticles exhibit a peak of magnetic loss at about 13 GHz, suggesting that magnetic loss and a natural resonance could be found at that frequency. Based on the measured complex permittivity and permeability, the reflection losses of paraffin-Ni（C） composites with different weight ratios of Ni（C） nanoparticles and coating thickness values are simulated according to the transmission line theory. An ex- cellent microwave absorption is obtained. To be proved by the experimental results, the reflection loss of composite with a coating thickness of 2 mm is measured by the Arch method. The results indicate that the maximum reflection loss reaches -26.73 dB at 12.7 GHz, and below -10 dB, the bandwidth is about 4 GHz. The fact that the measured absorption position is consistent with the calculated results suggests that a good electromagnetic match and a strong microwave absorption can be established in Ni（C） nanoparticles. The excellent Ni（C） microwave absorber is prepared by choosing an optimum layer number and the weight ratio of Ni（C） nanoparticles in paraffin-Ni（C） composites.

Studies on Electrochemical Property of LiFePO_4/C as Cathode Material for Lithium Ion Batteries

LiFePO4/C samples were prepared at different temperatures by adding sngar to the synthetic precursor. The samples were characterized by X-ray diffraction（XRD）. Their crystal phases show an olivine structure. Only the sample obtained at 700℃ has a larger discharge capacity, which has good electrochemical properties： its discharge specific capacity is 120. 3 mAh/g at a current of 0. 05 mA, and its capacity fade is very low after 20 cycles. It is demonstrated that the best synthetic temperature should be 700℃.

Two-dimensional CuO nanosheets-induced MOF composites and derivatives for dendrite-free zinc-ion batteries

Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries(AZIBs).In this work,we designed to grow zeolitic imidazolate framework-8(ZIF-8)uniformly on CuO nanosheets(NSs)and prepared carbon-coated CuZn alloy NSs(CuZn@C NSs)by calcination under H_(2)/Ar atmosphere.As reflected by extended X-ray absorption fine structure(EXAFS),density functional theory(DFT),in-situ Raman,the Cu–Zn and Zn–N bonds present in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and inhibit the formation of Zn dendrites.At the same time,CuZn@C NSs hinder the direct contact between zinc anode and electrolyte,preventing the occurrence of side reactions.More impressively,the symmetric cells constructed with CuZn@C NSs anodes exhibited excellent zinc plating/exfoliation performance and long life cycle at different current densities with low voltage hysteresis.In addition,low polarization,high capacity retention,long cycle life over 1000 cycles at 5 A∙g^(−1) were achieved when CuZn@C NSs were used as anodes for CuZn@C/V_(2)O_(5)full cells.

Efficient photocatalysis triggered by thin carbon layers coating on photocatalysts:recent progress and future perspectives

Solar-energy-driven photocatalysis,such as photocatalytic reduction of CO2,is promising simultaneously for the energy and environmental issues.Coating thin carbon layers with the thickness less than 10 nm on photocatalysts has been developed as an efficient strategy for enhancing the photocatalytic efficiency in recent years.In the present review,we summarize the crucial progress on carbon-coated photocatalysts.Origins for the improved light absorption,charge separation,reactant adsorption and photocatalytic stability on carbon-coated photocatalysts as well as the applications of carbon-coated photocatalysts are discussed.Future opportunities and challenges associated with carbon-coated photocatalysts are shown at the end of the review.We hope that the present review can trigger more deep insights on carbon-coated photocatalysts and provide new opportunities for developing low-cost but efficient photocatalysts.

A robust carbon coating of Na_(3)V_(2)(PO_(4))_(3)cathode material for high performance sodium-ion batteries

Na_(3)V_(2)(PO_(4))_(3)is a very prospective sodium-ion batteries(SIBs)electrode material owing to its NASICON structure and high reversible capacity.Conversely,on account of its intrinsic poor electronic conductivity,Na_(3)V_(2)(PO_(4))_(3)electrode materials confront with some significant limitations like poor cycle and rate performance which inhibit their practical applications in the energy fields.Herein,a simple two-step method has been implemented for the successful preparation of carbon-coated Na_(3)V_(2)(PO_(4))_(3)materials.As synthesized sample shows a remarkable electrochemical performance of 124.1 mAh/g at 0.1 C(1 C=117.6 mA/g),retaining 78.5 mAh/g under a high rate of 200 C and a long cycle-performance(retaining 80.7 mAh/g even after 10000 cycles at 20 C),outperforming the most advanced cathode materials as reported in literatures.

A new kind of magnetic targeting induction heating drug carrier and its physical and biological properties

Nano-carbon and iron composite—carbon-coated iron nanoparticles (CCINs) produced by carbon arc method can be used as a new kind of magnetic targeting induction heating drug carrier for cancer therapy. The structure and morphology of CCINs are studied by X-ray diffraction (XRD) and transmission electron microscope (TEM). Mossbauer spectra of these nanoparticles show that they contain only iron and carbon, without ferric carbide and ferric oxide. CCINs can be used as the magnetic drug carrier, with the effect of targeting magnetic induction heating in its inner core and higher drug adsorption in its nano-carbon shell outside because of its high specific surface area. CCINs can absorb Epirubicin (EPI) of 160 μg/mg measured by an optical spectrometer. In acute toxicity experiment with mice, the median lethal dose (LD50) of EPI is 16.9 mg/kg, while that of EPI-CCINs mixture is 20.7 mg/kg and none of the mice died after pure CCINs medication. The results show that pure CCINs belong to non-toxic grade and EPI delivery in mixture with CCINs can reduce its acute toxicity in mice. The magnetic properties of CCINs and their magnetic induction heating are investigated. The iron nanoparticle in its inner core has better magnetism with a good effect on targeting magnetic induction heating. When the CCINs are mixed with physiological salt water and are injected uniformly in pig’s liver, the temperature goes up to 48°C. While in the case that CCINs are filled in a certain section of pig’s liver, the temperature goes up to 52°C. In both cases the temperature is high enough to kill the cancer cell. CCINs have potential applications in cancer therapy.

Electronic modulation and structure engineered MoSe2 with multichannel paths as an advanced anode for sodium-ion half/full batteries

Owing to the abundance and low price of sodium,researches on sodium-ion batteries(SIBs)as a lithiumion battery(LIB)alternative are emerging as a consensus.It is crucial to develop electrode materials suitable for sodium storage.In recent years,two-dimensional(2 D)layered transition metal disulfide compounds(TMDs)have trigered interest in the realm of energy and environmental fields.In particular,MoSeis thought to be a suitable material for SIBs due to its wide original layer spacing and high conductivity.Herein,N-doped dual carbon-coated MoSewith multichannel paths(MoSe/multichannel carbon nanofibers(MCFs)@NC)is fabricated via electrospinning,followed by a selenation and carbonization process.The existence of a 3 D conductive network,abundant void spaces,and sufficient electron transportation pathways are conducive to rapid and fast charge transfer kinetics under volume expansion stress.When applied in SIBs,the MoSe/MCFs@NC shows a high capability(319 mA hg^(-1)at 10 A g^(-1)),as well as good cycling stability(303 mA h g^(-1)after 1100 cycles at 10 A g^(-1)).Furthermore,coupled with the Na_(3)V_(2)(PO_(4))_(2)O_(2)F cathode,the full cell also exhibits excellent performance.The theoretical calculation of the MoSe_(2)/MCFs@NC confirms that the superiority of its SIB performance is owing to the strong interaction between the double-doped carbon and MoSe.This scheme provides a wide space for preparing high-performance electrode materials for SIBs.