固废基气凝胶粒子电极的制备及电催化降解有机污染物的性能与机制

以废菌棒(MS)和赤泥(RM)为原料,经过煅烧得到粉末状废菌棒赤泥生物炭(MSRMBC).采用悬浮滴定CaCl_(2)法以海藻酸钠(SA)为骨架的凝胶对MSRMBC进行包埋制得气凝胶粒子电极(MSRMBC@SA),并利用扫描电子显微镜(SEM)、能量色散谱(EDS)、傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、氮气吸附-脱附实验和循环伏安曲线(CV)对其进行表征分析.利用MSRMBC@SA构建三维电芬顿体系(3D-EFMSRMBC@SA),以卡马西平(CBZ)为模型化合物,考察了MSRMBC@SA投加量、电压、曝气量和pH值对MSRMBC@SA电催化性能的影响,最佳降解条件下CBZ(10 mg/L)的降解率为86.05%.因MSRMBC@SA具有良好的pH值调节能力,故体系受pH值影响较小.自由基猝灭、电子自旋共振(ESR)及X射线光电子能谱(XPS)表征结果表明,·OH为主要活性物种,MSRMBC@SA在CBZ降解过程中起到了关键的催化作用.研究发现,MSRMBC@SA稳定性较好,且3D-EF-MSRMBC@SA较2D-EF及3D-EF-MSRMBC具有更低的能耗和更佳的降解效果.MSRMBC@SA可有效降低CBZ溶液的生物毒性,对实际CBZ抗生素废水降解具有良好的应用前景.

垂直型直流接地极的电极结构对溢流密度的影响

[目的]垂直型直流接地极的溢流密度是关乎接地极性能的关键参数,因此电极结构对溢流密度的影响值得研究。[方法]针对垂直接地极的结构特点,分析了子电极数量、子电极长度、子电极间的间隙距离、电极井截面对溢流密度大小和均匀程度的影响。[结果]研究表明:溢流密度大小与子电极总长度有关,与子电极分段数量和间隙距离几乎无关;而溢流不均匀程度与间隙距离和电极井截面有关。[结论]结合计算分析结果提出了优化的垂直型电极结构。

The use of carbon-based particle electrodes in three-dimensional electrode reactors for wastewater treatment

The use of three-dimensional(3D)electrodes in water treatment is competitive because of their high catalytic efficiency,low energy consumption and promising development.The use of particle electrodes is a key research focus in this technology.They are usually in the form of particles that fill the space between the cathode and anode,and the selection of materials used is important.Carbon-based materials are widely used because of their large specific surface area,good adsorption performance,high chemical stability and low cost.The principles of 3D electrode technology are introduced and recent research on its use for degrading organic pollutants using carbon-based particle electrodes is summarized.The classification of particle electrodes is introduced and the challenges for the future development of carbon-based particle electrodes in wastewater treatment are discussed.

A review of anode materials for sodium ion batteries

Lithium-ion batteries(LIBs)are used in electric vehicles and portable smart devices,but lithium resources are dwindling and there is an increasing demand which has to be catered for.Sodium ion batteries(SIBs),which are less costly,are a promising replacement for LIBs because of the abundant natural reserves of sodium.The anode of a SIB is a necessary component of the battery but is less understood than the cathode.This review outlines the development of various types of anodes,including carbonbased,metallic and organic,which operate using different reaction mechanisms such as intercalation,alloying and conversion,and considers their challenges and prospects.Strategies for modifying their structures by doping and coating,and also modifying the solid electrolyte interface are discussed.In addition,this review also discusses the challenges encountered by the anode of SIBs and the solutions.

A review of the carbon coating of the silicon anode in highperformance lithium-ion batteries

In the development of rechargeable lithium ion batteries(LIBs),silicon anodes have attracted much attention because of their extremely high theoretical capacity,relatively low Li-insertion voltage and the availability of silicon resources.However,their large volume expansion and fragile solid electrolyte interface(SEI)film hinder their commercial application.To solve these problems,Si has been combined with various carbon materials to increase their structural stability and improve their interface properties.The use of different carbon materials,such as amorphous carbon and graphite,as three-dimensional(3D)protective anode coatings that help buffer mechanical strain and isolate the electrolyte is detailed,and novel methods for applying the coatings are outlined.However,carbon materials used as a protective layer still have some disadvantages,necessitating their modification.Recent developments have focused on modifying the protective carbon shells,and substitutes for the carbon have been suggested.

Rate and Cycling Performance of Ti and Cu Dopedβ-NaMnO_(2) as Cathode of Sodium-ion Battery

Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structure,which has attracted significant attention due to its structural robustness and relatively high specific capacity.However,it has short cycle life and poor rate capability.To address these issues,Ti atoms,known for enhancing structural stability,and Cu atoms,which facilitate desodiation,were doped intoβ-NaMnO_(2) by first-principles calculation and crystal orbital Hamilton population(COHP)analysis.β-NaMn_(0.8)Ti_(0.1)Cu_(0.1)O_(2) exhibits a notable increase in reversible specific capacity and remarkable rate properties.Operating at a current density of 0.2C(1C=219 mA·g^(–1))and within a voltage range of 1.8–4.0 V,the modified material delivers an initial discharge capacity of 132 mAh·g^(–1).After charge/discharge testing at current densities of 0.2C,0.5C,1C,3C,and 0.2C,the material still maintains a capacity of 110 mA h·g^(–1).The doping of Ti atoms slows down the changes in the crystal structure,resulting in only minimal variation in the lattice constant c/a during the desodiation process.Mn and Cu engage in reversible redox reactions at voltages below 3.0 V and around 3.5 V,respectively.The extended plateau observed in the discharge curve below 3.0 V signifies that Mn significantly contributes to the overall battery capacity.This study provides insights into modifyingβ-NaMnO_(2) as a cathode material,offering experimental evidence and theoretical guidance for enhancing battery performance in Na-ion batteries.

Electrolyte engineering for optimizing anode/electrolyte interface towards superior aqueous zinc-ion batteries:A review

Aqueous zinc-ion batteries(AZIBs) are promising candidates for the large-scale energy storage systems due to their high intrinsic safety,cost-effectiveness and environmental friendliness.However,issues such as dendrite growth,hydrogen evolution reaction,and interfacial passivation occurring at the anode/electrolyte interface(AEI) have hindered their practical application.Constructing a stable AEI plays a key role in regulating zinc deposition and improving the cycle life of AZIBs.The fundamentals of AEI and the challenges faced by the Zn anode due to unstable interfaces are discussed.A comprehensive summary of electrolyte regulation strategies by electrolyte engineering to achieve a stable Zn anode is provided.The effectiveness evaluation techniques for stable AEI are also analyzed,including the interfacial chemistry and surface morphology evolution of the Zn anode.Finally,suggestions and perspectives for future research are offered about enabling a durable and stable AEI via electrolyte engineering,which may pave the way for developing high-performance AZIBs.

Remote electron effects and π-π interactions of α-diimine nickel complexes

The seminal report ofα-diimine palladium and nickel catalysts in 1995 represented a major breakthrough in the preparation of functionalized polyolefin materials.Owing to the high abundance and low cost of nickel,nickel-based catalysts have great application prospects in the industrialization process of olefin coordination polymerization.In this work,various N-aryl substituents with different electronic effects were synthesized and introduced intoα-diimine ligands.The aspreparedα-diimine nickel catalysts showed high polymerization activity(0.9×10^(7)–3.0×10^(7)g·mol^(−1)·h^(−1))in ethylene polymerization,generating polyethylene products with adjustable molecular weights(Mn values:7.4×10^(4)–146.9×10^(4)g·mol^(−1))and branching densities(31/1000 C–68/1000 C).The resulting polyethylene products showed excellent mechanical properties,with high tensile strength(up to 25.0 MPa)and high strain at break values(up to 3890%).The copolymerization of ethylene and polar monomers can also be achieved by these nicekel complexes,ultimately preparing functionalized polyolefins.

Nitrogen⁃doped 3D graphene⁃carbon nanotube network for efficient lithium storage

A 3D nitrogen⁃doped graphene/multi⁃walled carbon nanotube(CS⁃GO⁃NCNT)crosslinked network mate⁃rial was successfully synthesized utilizing chitosan and melamine as carbon and nitrogen sources,concomitant with the incorporation of multi⁃wall carbon nanotubes and employing freeze drying technology.The material amalgamates the merits of 1D/2D hybrid carbon materials,wherein 1D carbon nanotubes confer robustness and expedited elec⁃tron transport pathways,while 2D graphene sheets facilitate rapid ion migration.Furthermore,the introduction of nitrogen heteroatoms serves to furnish additional active sites for lithium storage.When served as an anode material for lithium⁃ion batteries,the CS⁃GO⁃NCNT electrode delivered a reversible capacity surpassing 500 mAh·g^(-1),mark⁃edly outperforming commercial graphite anodes.Even after 300 cycles at a high current density of 1 A·g^(-1),it remained a reversible capacity of up to 268 mAh·g^(-1).

First-Principles Study of Blue Phosphorene and Graphene Intralayer Heterostructure as Anode Materials for Rechargeable Li-lon Batteries

There is an ideal desire to develop the high-performance anodes materials for Liion batteries(LIBs),which requires not onlyhigh stability and reversibility,but also rapidcharging/discharging rate.In this work,webuiltablue phosphorene-graphene(BlueP-G)intralayer heterostructure by connecting BlueP and graphene monolayers at zigzag edges with covalent bonds.Based on the density functional theory simulation,the electronic structure of the heterostructure,Li adsorption and Li diffusion on heterostructure were systematically investigated.Compared with the pristine BlueP,the existence of graphene layer increases the overall conductivity of BlueP-G intralayer heterostructure.The significantly enhanced adsorption energy indicates the Li deposition on anode surface is energetically favored.The fast diffusion of Li with energy barrier as low as 0.02-0.09 eV indicates the growth of Li dendrite could be suppressed and the stability and reversibility of the battery will be increased.With a combination of increased conductivity of electronic charge,excellent Li adsorption and Li mobility on surface,BlueP-G intralayer heterostructure with zigzag interface is quite promising in the application of anode material for Li-ion batteries.

Synthesis of pitch-derived carbon anodes for high-performance potassium-ion batteries

Potassium-ion batteries(PIBs)hold promise for large-scale energy storage,necessitating the development of high-performance anode materials.Carbons with the advantage of structural versatility,are recognized as the most promising anode materials for their commercialization,however the relationship between the carbon anode structure and its electrochemical performance remains unclear.A series of pitch-based soft carbons with different structures were fabricated using carbonization temperatures in the range 600–1400℃,and their changes in carbon configuration and K-storage performance as a function of carbonization temperature were investigated.Correlations between the carbon crystal size and the low-potential plateau region capacity and between the degree of structural disorder of the carbons with their sloping region capacity were revealed.Among all samples,that obtained by carbonization at 700℃had a relatively high degree of disorder and a large interlayer spacing,and had a high reversible capacity of 329.4 mAh g^(-1) with a high initial coulombic efficiency of 72.81%,and maintained a high capacity of 144.2 mAh g^(-1) at the current rate of 5 C.These findings improve our fundamental understanding of the K-storage process in carbon anodes,and thus facilitate the advance of PIBs.

First-Principles Insights into Pt_(n)/ZnO(0001)Catalyst:Regulation of Metal-Support Interaction through Surface Polarity

Polar surfaces are prevalent in metal oxides,the interactions between surface species with polar surfaces are different from those with non-polar surfaces,a thorough understanding of the interactions is key to regulate the performance of heterogeneous catalysts.In this work,we delve into the interaction of Pt_(n)(n=1-4)with polar ZnO(0001)-Zn and ZnO(0001)-O,and the influence of the surface polarity on the electronic structures and reactivity of Pt_(n) by using density functional theory calculations.The results suggest distinct differences in electronic structures of two exposed terminations,leading to different interactions with Pt_(n).The interaction between Pt_(n) and two terminations not only stabilizes the surface and clusters through polar compensation,but also induces opposite charges on the cluster at two terminations.Remarkably,the Pearson correlation coefficient reveals the interdependency between the electronic states of Pt_(n) and its performance in terms of small molecule adsorption/activation.These observations demonstrate the crucial role of surface polarity in regulating the electronic states and catalytic performance of active sites,and offer a possible design principle for supported catalysts.

A review of hard carbon anodes for rechargeable sodium-ion batteries

Hard carbons(HCs)are recognized as potential anode materials for sodium-ion batteries(SIBs)because of their low cost,environmental friendliness,and the abundance of their precursors.The presence of graphitic domains,numerous pores,and disordered carbon layers in HCs plays a significant role in determining their sodium storage ability,but these structural features depend on the precursor used.The influence of functional groups,including heteroatoms and oxygen-containing groups,and the microstructure of the precursor on the physical and electrochemical properties of the HC produced are evaluated,and the effects of carbonization conditions(carbonization temperature,heating rate and atmosphere)are also discussed.

Metal-organic framework-derived porous carbon for the advanced aqueous zinc-ion hybrid capacitor

Aqueous zinc ion hybrid capacitors(ZIHCs)are considered one of the most promising electrochemical energy storage systems due to their high safety,environmental friendliness,low cost,and high power density.However,the low energy density and the lack of sustainable design strategies for the cathodes hinder the practical application of ZIHCs.Herein,we design the N and O co-doped porous carbon cathode by annealing metal-organic framework(ZIF-8).ZIF-8 retains the original dodecahedral structure with a high specific surface(2814.67 m^(2)/g)and I_(G)/I_(D) ratio of 1.0 during carbonization and achieves self-doping of N and O heteroatoms.Abundant defect sites are introduced into the porous carbon to provide additional active sites for ion adsorption after the activation of carbonized ZIF-8 by KOH treatment.The ZIHCs assembled with modified ZIF-8 as the cathode and commercial zinc foil as the anode show an energy density of 125 W∙h/kg and a power density of 79 W/kg.In addition,this ZIHCs device achieves capacity retention of 77.8%after 9000 electrochemical cycles,which is attributed to the diverse pore structure and plentiful defect sites of ZIF-8-800(KOH).The proposed strategy may be useful in developing high-performance metal-ion hybrid capacitors for large-scale energy storage.

Defect-rich N/O-co-doped porous carbon frameworks as anodes for superior potassium and sodium-ion batteries

Carbon with its high electrical conductivity,excellent chemical stability,and structure ability is the most promising an-ode material for sodium and potassium ion batteries.We developed a defect-rich porous carbon framework(DRPCF)built with N/O-co-doped mesoporous nanosheets and containing many defects using porous g-C_(3)N_(4)(PCN)and dopamine(DA)as raw materials.We prepared samples with PCN/DA mass ratios of 1/1,2/1 and 3/1 and found that the one with a mass ratio of 2/1 and a carbonization temperature of 700℃ in an Ar atmosphere(DRPCF-2/1-700),had a large specific surface area with an enormous pore volume and a large number of N/O heteroatom active defect sites.Because of this,it had the best pseudocapacitive sodium and potassium ion stor-age performance.A half battery of Na//DRPCF-2/1-700 maintained a capacity of 328.2 mAh g^(-1) after being cycled at 1 A g^(-1) for 900 cycles,and a half battery of K//DRPC-2/1-700 maintained a capacity of 321.5 mAh g^(-1) after being cycled at 1 A g^(-1) for 1200 cycles.The rate capability and cycling stability achieved by DRPCF-2/1-700 outperforms most reported carbon materials.Finally,ex-situ Raman spectroscopy analysis result confirms that the filling and removing of K^(+)and Na^(+)from the electrochemically active defects are responsible for the high capacity,superior rate and cycling performance of the DRPCF-2/1-700 sample.

Influence of anodization conditions on deposition of hydroxyapatite on α/β Ti alloys for osseointegration:Atomic force microscopy analysis

Integrating titanium-based implants with the surrounding bone tissue remains challenging.This study aims to explore the impact of different anodization voltages(20−80 V)on the surface topography of two-phase(α/β)Ti alloys and to produce TiO_(2) films with enhanced bone formation abilities.Scanning electron microscopy coupled with energy dispersive spectroscopy(SEM−EDS)and atomic force microscopy(AFM)were applied to investigate the morphological,chemical,and surface topography of the prepared alloys and to confirm the growth of hydroxyapatite(HA)on their surfaces.Results disclosed that the surface roughness of TiO_(2) films formed on Ti−6Al−7Nb alloys was superior to that of Ti−6Al−4V alloys.Ti−6Al−7Nb alloy anodized at 80 V had the highest yields of HA after immersion in simulated body fluid with enhanced HA surface coverage.The developed HA layer had a mean thickness of(128.38±18.13)μm,suggesting its potential use as an orthopedic implantable material due to its promising bone integration and,hence,remarkable stability inside the human body.

Preparation of uniform flower-like CuO and flower-like CuO/graphene composite and their application in lithium ion batteries

Flower-like CuO and flower-like CuO/graphene composite were prepared successfully by hydrothermal method. They were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, temperature-programmed reduction, and thermogravimetric analysis. It is found that the flower-like CuO microspheres, which are composed of CuO nanosheets, possess an average diameter of 4.2 μm and a Brunauer–Emmett–Teller surface area of 12.6 m2/g. Compared with the flower-like CuO, the obtained flower-like CuO/graphene composite shows an enhanced electrochemical performance with a higher capacity of 603 mA-h/g at 0.1 C rate and 382 mA-h/g at 1 C rate, and exhibits a better cycle stability with a high capacity retention of 95.5 % after 50 cycles even though at 1 C rate.

Effect of Mn-doping on performance of Li_3V_2(PO_4)_3/C cathode material for lithium ion batteries

Li3V2-2/3xMnx（PO4）3（0≤x≤0.12） powders were synthesized by sol-gel method. The effect of Mn2＋-doping on the structure and electrochemical performances of Li3V2（PO4）3/C was characterized by XRD, SEM, XPS, galvanostatic charge /discharge and electrochemical impedance spectroscopy（EIS）. The XRD study shows that a small amount of Mn2＋-doped does not alter the structure of Li3V2（PO4）3/C materials, and all Mn2＋-doped samples are of pure single phase with a monoclinic structure （space group P21/n）. The XPS analysis indicates that valences state of V and Mn are ＋3 and ＋2 in Li3V1.94Mn0.09（PO4）3/C, respectively, and the citric acid in raw materials was decomposed into carbon during calcination, and residual carbon exists in Li3V1.94Mn0.09（PO4）/C. The results of electrochemical measurements show that Mn2＋-doping can improve the cyclic stability and rate performance of these cathode materials. The Li3V1.94Mn0.09（PO4）3/C cathode material shows the best cyclic stability and rate performance. For example, at the discharge current density of 40 mA/g, after 100 cycles, the discharge capacity of Li3V1.94Mn0.09（PO4）3/C declines from initial 158.8 mA·h/g to 120.5 mA·h/g with a capacity retention of 75.9%; however, that of the Mn-undoed sample declines from 164.2 mA·h/g to 72.6 mA·h/g with a capacity retention of 44.2%. When the discharge current is increased up to 1C, the intial discharge capacity of Li3V1.94Mn0.09（PO4）3/C still reaches 146.4 mA·h/g, and the discharge capacity maintains at 107.5 mA·h/g after 100 cycles. The EIS measurement indicates that Mn2＋-doping with a appropriate amount of Mn2＋ decreases the charge transfer resistance, which is favorable for the insertion/extraction of Li＋.

Synthesis of nanostructured Li_2FeSiO_4/C cathode for lithium-ion battery by solution method

Nanosphere-like Li2FeSiO4/C was synthesized via a solution method using sucrose as carbon sources under a mild condition of time-saving and energy-saving, followed by sintering at high temperatures for crystallization. The amount of carbon in the composite is less than 10% （mass fraction）, and the X-ray diffraction result confirms that the sample is of pure single phase indexed with the orthorhombic Pmn21 space group. The particle size of the Li2FeSiO4/C synthesized at 700 °C for 9 h is very fine and spherical-like with a size of 200 nm. The electrochemical performance of this material, including reversible capacity, cycle number, and charge-discharge characteristics, were tested. The cell of this sample can deliver a discharge capacity of 166 mA-h/g at C/20 rate in the first three cycles. After 30 cycles, the capacity decreases to 158 mA-h/g, and the capacity retention is up to 95%. The results show that this method can prepare nanosphere-like Li2FeSiO4/C composite with good electrochemical performance.

Effect of electrolytic MnO_2 pretreatment on performance of as-prepared LiMn_2O_4

To investigate the effect of electrolytic MnO2 （EMD） on the performance of LiMn2O4, several pretreatment methods, such as acid treating, presintering and impregnating with chromic salt, were used. The pretreated EMD and prepared LiMn2O4 were characterized by X-ray diffraction and inductively coupled plasma emission spectrometry. Charge and discharge tests of Li/LiMn2O4 batteries were also employed to evaluate electrochemical performance. The experimental results show that inorganic impurity contents in EMD decrease remarkably after acid treating; presintering EMD can remove adsorbent water and organic impurity, enlarge pore space and increase active reaction sites; pre-doping chromium in EMD can form more homogenous compound substance LiCr0.05Mn1.95O4, which shows better structural stability and capacity retention.