In Situ Atomic Reconstruction Engineering Modulating Graphene-Like MXene-Based Multifunctional Electromagnetic Devices Covering Multi-Spectrum

With the diversified development of big data,detection and precision guidance technologies,electromagnetic(EM)functional materials and devices serving multiple spectrums have become a hot topic.Exploring the multispectral response of materials is a challenging and meaningful scientific question.In this study,MXene/TiO_(2)hybrids with tunable conduction loss and polarization relaxation are fabricated by in situ atomic reconstruction engineering.More importantly,MXene/TiO_(2)hybrids exhibit adjustable spectral responses in the GHz,infrared and visible spectrums,and several EM devices are constructed based on this.An antenna array provides excellent EM energy harvesting in multiple microwave bands,with|S11|up to−63.2 dB,and can be tuned by the degree of bending.An ultra-wideband bandpass filter realizes a passband of about 5.4 GHz and effectively suppresses the transmission of EM signals in the stopband.An infrared stealth device has an emissivity of less than 0.2 in the infrared spectrum at wavelengths of 6-14μm.This work can provide new inspiration for the design and development of multifunctional,multi-spectrum EM devices.

Layer-Contacted Graphene-Like BN/Ultrathin Bi_(3)O_(4)Br Stacking for Boosting Photocatalytic Molecular Oxygen Activation

Novel graphene-like boron nitride(BN)/Bi_(3)O_(4)Br photocatalysts have been controllably synthesized through a facile solvothermal method for the first time. Layer contact stacking between graphene-like BN and ultrathin Bi_(3)O_(4)Br was achieved with strong interaction. Dehalogenation is designed to harvest more visible light, and the ultrathin structure of Bi_(3)O_(4)Br is designed to accelerate charge transfer from inside to the surface. After graphene-like BN was engineered, photocatalytic performance greatly improved under visible light irradiation. Graphene-like BN can act as a surface electron-withdrawing center and adsorption center, facilitating molecular oxygen activation. O_(2)^(·-)was determined to be the main active species during the degradation process through analyses of electron spin resonance and XPS valence band spectra.

Facile Synthesis of N-Doped Graphene-Like Carbon Nanoflakes as Efficient and Stable Electrocatalysts for the Oxygen Reduction Reaction

A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C_3N_4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6,show the highest N content of ~6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of ~66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal–air batteries.

Triple-phase interfaces of graphene-like carbon clusters on antimony trisulfide nanowires enable high-loading and long-lasting liquid Li_(2)S_(6)-based lithium-sulfur batteries

High performance of lithium-sulfur batteries have been dragged down by their shuttling behavior which is complicated multiphase transition-based 16-electron redox reactions of the S8/Li2 S.In this article,the triple-phase interfaces of graphene-like carbon clusters on antimony trisulfide(C-Sb_(2)S_(3))nanowires are tailored to design a multifunctional polysulfide host which can inhibit migration of polysulfides and accelerate conversion kinetics of redox electrochemical reactions.Benefiting from the triple-interface design of polysulfides/Sb_(2)S_(3)/carbon clusters,the C-Sb_(2)S_(3) electrode not only anchors polysulfide migration by the synergistic effect of Sb,S,and C atoms as interfacial active sites,but also the graphene-like carbon clusters shorten the diffusion paths to further favor redox electron/ion transport through the liquid(electrolyte/polysulfide)and solid(Li2 S/S8,carbon clusters,and Sb_(2)S_(3))-based triple-phases.Therefore,these Li_(2)S_(6)-based C-Sb_(2)S_(3) cells possess high sulfur loading,excellent cycling stability,impressive specific capacity,and great rate capability.This work of interfacial engineering reveals insight for powering reaction kinetics in the complicated multistep catalysis reaction with multiphase evolution-based chargetransfer/non-transfer processes.

Perforated nitrogen-rich graphene-like carbon nanolayers supported Cu-In catalyst for boosting CO_(2) electroreduction to CO

The combination of a powerful CO_(2)-enriching carrier and robust active component provides a new idea for the construction of efficient catalysts for electrocatalytic CO_(2)reduction.Herein,novel perforated nitrogen-rich graphene-like carbon nanolayers(PNGC)are prepared from biomass derivatives,which promotes the oriented deposition of In-doped Cu_(2)(OH)_(3)(NO_(3))nanosheet patches.A robust Cu-In/PNGC composite catalyst is then obtained via simple in-situ electrochemical reduction.Unsurprisingly,CuIn/PNGC exhibits a CO Faradaic efficiency(FECO)of 91.3%and a remarkable CO partial current density(jCO)of 136.4 m A cm^(-2)at a moderate overpotential of 0.59 V for electrocatalytic CO_(2)reduction reaction(CO_(2)RR).DFT calculations and experimental studies indicate that the strong carrier effect of PNGC makes PNGC carried Cu-In nanosheets improved the adsorption capacity of CO_(2)gas,reconfigured electronic structure,and reduced free energy of key intermediate formation,thereby the CO_(2)activation and conversion are promoted.

Adsorptions of metal adatoms on graphene-like BC3 and their rich electronic properties： A first-principles study

Density functional calculations have been performed to investigate the adsorption of twenty two different kinds of metal adatoms on graphene-like BC3. In contrast to the graphene adsorbed with adatoms, the BC3 with adatoms shows many interesting properties.（1） The interaction between the metal adatoms and the BC3 sheet is remarkably strong. The Li, Na, K, and Ca possess the binding energies larger than the cohesive energies of their corresponding bulk metals.（2）The Li, Na, and K adatoms form approximately ideal ionic bonds with BC3, while the Be, Mg, and Ca adatoms form ionic bonds with BC3 with slight hybridization of covalent bonds. The Al, Ga, In, Sn, and all transition metal adatoms form covalent bonds with BC3.（3） For all the structures studied, there exhibit metal, half-metal, semiconducting, and spin-semiconducting behaviors. Especially, the BC3 with Co adatom shows a quantum anomalous Hall（QAH） phase with a Chern number of -1 based on local density approximation calculations.（4） For Li, Na, K, Ca, Ga, In, Sn, Ti, V, Cr,Ni, Pd, and Pt, there exists a trend that the adatom species with lower ionization potential have lower work function. Our results indicate the potential applications of functionalization of BC3 with metal adatoms.

Compensation temperatures and hysteresis behaviors of a graphene-like trilayer

This work focuses on the ground-state phase diagram,the compensation temperatures and the critical behaviors of a ferrimagnetic graphene-like trilayer induced by crystal fields and exchange couplings.The simulation results show that a negative decrease in crystal field or an increase in exchange coupling can increase the critical temperature.More importantly,an M curve with double compensation temperatures can be observed,which is not predicted by the Neel theory.This remarkable compensation phenomenon has potential application value in the field of magnetic recording.

Compensation temperature and hysteresis behaviors of a graphene-like bilayer:Monte Carlo Study

Using the Monte Carlo method,the compensation temperature and hysteresis loops of a ferrimagnetic mixed spin-3/2 and spin-5/2 Ising-type graphene-like bilayer are investigated induced by different physical parameters such as crystal field,exchange coupling,external magnetic field,and temperature.The variations of magnetization,magnetic susceptibility,specific heat,and internal energy with the change of temperature are discussed.In addition,we also plot the phase diagrams including transition temperature and compensation temperature.Finally,multiple hysteresis loops under certain parameters are given.

From graphite to porous graphene-like nanosheets for high rate lithium-ion batteries

Graphene nanosheets possess a promising potential as electrodes in Li-ion batteries （LIBs）; consequently, the development of low-cost and high-productivity synthetic approaches is crudal. Herein, porous grapheneqike nanosheets （PGSs） have been synthesized from expandable graphite （EG） by initially intercalating phosphoric acid, and then performing annealing to enlarge the interlayer distance of EG, thus fadlitating the successive intercalation of zinc chloride. Subsequently, the following pyrolysis of zinc chloride in the EG interlayer promoted the formation of the porous PGS structure; meanwhile, the gas produced during the formation of the porous structure could exfoliate the EG to graphene-like nanosheets. The synthetic PGS material used as LIB anode exhibited superior Li＋ storage performance, showing a remarkable discharge capacity of 830.4 mAh.g-1 at 100 mA.g-1, excellent rate capadty of 211.6 mAh＇g-1 at 20,000 mA-g-1, and excellent cycle performance （near 100% capacity retention after 10,000 cycles）. The excellent rate performance is attributed to the Li＋ ion rapid transport in porous structures and the high electrical conductivity of graphene-like nanosheets. It is expected that PGS may be widely used as anode material for high-rate LIBs via this facile and low-cost route by employing EG as the raw material.

Analysis of graphene-like activated carbon derived from rice straw for application in supercapacitor

Activated carbons with large surface area, abundant microporosity and low cost are the most commonly used electrode materials for energy storage devices. However, activated carbons are conventionally made from fossil precursors, such as coal and petroleum, which are limited resources and easily aggregate large block in high temperature carbonization processes. In this novel work, we examined the use of rice straw as a potential alternative carbon source precursor for the production of graphene-like active carbon. A very slack activated carbon with ultra-thin two-dimensional （2D） layer structure was prepared by our proposed approach in this work, which includes a pre-treatment process and potassium hydroxide activation at high temperatures. The obtained active carbon derived from rice straw exhibited a capacitance of 255 Fig at 0.5 A/g, excellent rate capability, and long cycling capability （98% after 10,000 cycles）.

Photocatalytic water splitting of ternary graphene-like photocatalyst for the photocatalytic hydrogen production

In recent times,there has been an increasing demand for energy which has resulted in an increased consumption of fossil fuels thereby posing a number of challenges to the environment.In the course finding possible solutions to this environmental canker,solar photocatalytic water splitting to produce hydrogen gas has been identified as one of the most promising methods for generating renewable energy.To retard the recombination of photogenerated carriers and improve the efficiency of photocatalysis,the present paper reports a facile method called the hydrothermal method,which wa s used to prepare ternary graphene-like photocatalyst.A“Design Expert”was used to investigate the influence of the loading weight of Mo and GO as well as the temperature of hydrothermal reaction and their interactions on the evolution of hydrogen(H 2)in 4 h.The experimental results showed that the ternary graphene-like photocatalyst has a strong photocatalytic hydrogen production activity compared to that of pure SiC.In particular,the catalyst added 2.5 wt%of GO weight yielded the highest quantum of 21.69%at 400-700 nm of wavelength.The optimal evolution H2 in 4 h conditions was obtained as follows:The loading weight of Mo was 8.19 wt%,the loading weight of GO was 2.02 wt%,the temperature of the hydrothermal reaction was 200.93℃.Under the optimum conditions,the evolution of H2 in 4h could reach 4.2030 mL.

Oxidation layering mechanism of graphene-like MoS2 prepared by the intercalation-detonation method

Graphene-like MoS2 has attracted significant interest because of its unique electronic, optical, and catalytic properties with two-dimensional lamellar structure. Three kinds of intercalated MoS2 samples were prepared using different oxidation layering methods, which are the first steps of intercalation-detonation. The oxidation layering mechanism of graphene-like MoS2 was systematically characterized using Fourier transform infrared, X-ray photoelectron, and Raman spectroscopy techniques. The bulk MoS2 sample was gradually oxidized from the edge to the interlayer in the presence of concentrated H2SO4 and KMnO4. A large number of hydroxyl groups were bonded to the sulfur atom layer, forming S-OH bonds in the basal planes of the MoS2 structure. The addition of deionized water to concentrated H2SO4 generated a large amount of heat, promoting the generation of more S-OH bonds, destroying residual Van der Waals forces between the layers, and finally stripping off parts of the flakes. The continuous addition of deionized water in the high temperature stage resulted in the largest oxidative intercalation effect. Additional136 the I/factor was determined to compare the intensities of Blu and Alg peaks in the Raman spectra and quantify the effect of oxidative intercalation. The highest value of q was obtained when deionized water was added continuously during the preparation of intercalated MoS2.

Graphene-like h-BN supported polyhedral NiS_(2)/NiS nanocrystals with excellent photocatalytic performance for removing rhodamine B and Cr(Ⅵ)

Human health is deteriorating due to the effluent containing heavy metal ions and organic dyes.Hence,photoreduction of Cr(Ⅵ)to Cr(Ⅲ)and degradation of rhodamine B(RhB)using a novel photocatalyst is particularly important.In this work,h-BN/NiS_(2)/NiS composites were prepared via a simple solvothermal method and a double Z-scheme heterojunction was constructed for efficiently removing RhB and Cr(Ⅵ).The 7 wt-%h-BN/NiS_(2)/NiS composites were characterized via a larger specific surface area(15.12 m^(2)·g^(−1)),stronger light absorption capacity,excellent chemical stability,and high yield of electrons and holes.The experimental result indicated that the photoreduction efficiency of the 7 wt-%h-BN/NiS_(2)/NiS photocatalyst achieved 98.5%for Cr(Ⅵ)after 120 min,which was about 3 times higher than that of NiS_(2)/NiS(34%).However,the removal rate of RhB by the 7 wt-%h-BN/NiS_(2)/NiS photocatalyst reached 80%.This is due to the double Z-scheme heterojunction formed between NiS_(2)/NiS and h-BN,which improved the charge separation efficiency and transmission efficiency.Besides,the influence of diverse photogenerated electron and hole scavengers upon the photoreduction of Cr(Ⅵ)was studied,the results indicated that graphene-like h-BN promoted transportation of photoinduced charges on the surface of the h-BN/NiS_(2)/NiS photocatalyst via the interfacial effects.

Dynamic magnetic properties of Ising graphene-like monolayer

Dynamic magnetic properties of the mixed-spin(3/2,5/2)Ising graphene-like monolayer in an oscillating magnetic field are studied by means of Monte Carlo simulation.The effects of Hamiltonian parameters such as crystal field and time-dependent oscillating magnetic field on the dynamic order parameter,susceptibility and internal energy of the system are well presented and explained.Moreover,much attention has also been dedicated to the phase diagrams with different parameters in order to better comprehend the impacts of these parameters on the critical temperature.Our results reveal that the crystal fields of two sublattices have similar effects on the critical temperature,but the bias field and amplitude of oscillating field have opposite effects on it.We hope that our research can be of guiding significance to the theoretical and experimental studies of graphene-like monolayer.

High energy superstable hybrid capacitor with a self-regulated Zn/electrolyte interface and 3D graphene-like carbon cathode

Rechargeable aqueous zinc ion hybrid capacitors(ZIHCs),as an up-and-comer aqueous electrochemical energy storage system,endure in their infancy because of the substandard reversibility of Zn anodes,structural deterioration of cathode materials,and narrow electrochemical stability window.Herein,a scalable approach is described that addresses Zn-anode/electrolyte interface and cathode materials associated deficiencies and boosts the electrochemical properties of ZIHCs.The Zn-anode/electrolyte interface is self-regulated by alteration of the traditional Zn2+electrolyte with Na-based supporting salt without surrendering the cost,safety,and green features of the Zn-based system which further validates the excellent reversibility over 1100 h with suppressed hydrogen evolution.The deficits of cathode materials were overcome by using a high-mass loaded,oxygen-rich,3D,multiscaled graphene-like carbon(3D MGC)cathode.Due to the multiscaled texture,high electronic conductivity,and oxygen-rich functional groups of 3D MGC,reversible redox capacitance was obtained with a traditional adsorption/desorption mechanism.Prototype ZIHCs containing the modified electrolyte and an oxygen-rich 3D MGC cathode resulted in battery-like specific energy(203 Wh kg1 at 1.6 A g^(-1))and supercapacitor-type power capability(4.9 kW kg1 at 8 A g^(-1))with outstanding cycling durability(96.75%retention over 30000 cycles at 10 A g^(-1)).These findings pave the way toward the utilization of highly efficient ZIHCs for practical applications.

Double-sided surface functionalization: An effective approach to stabilize and modulate the electronic structure of graphene-like borophene

Graphene-like borophene was theoretically proposed and recently synthesized on Al(111)surface,however,how to conquer its structural instability is still an open question.By means of density functional theory computations,we theoretically predicted that honeycomb borophene can be well stabilized by double-sided surface passivation with monovalent functional groups(X=F,Cl,Br,I,OH,and NH2)due to the electron redistributions.The system undergoes the transition from metallic to semiconducting upon functionalization,while the energy gap depends on the choice of functional groups.Under external strain,the gap values can be manipulated over a broad range.Our further calculations indicated that the functionalized borophene possesses moderate and anisotropic carrier mobility,which is comparable to or even higher than some 2D materials such as MoS2 and phosphorene.Our work provides a feasible strategy to effectively stabilize the graphene-like borophene and tune the electronic properties with great potentials for electronic applications.

Porous Carbon Grown by Chemical Vapor Deposition on Copper Substrates

Amorphous porous carbon was synthesized by chemical vapor deposition on copper substrates. The average size of the pores is around 1.2 microns with some small pores decorating the big ones. Lamellar samples of this carbonaceous material can be separated from the copper support and may be useful as electrode due to its low electrical resistivity of the order of 0.4 Ωcm.

Graphitized Cu-β-cyclodextrin polymer driving an efficient dual-reaction-center Fenton-like process by utilizing electrons of pollutants for water purification

Excessive consumption of energy and resources is a major challenge in wastewater treatment.Here,a novel heterogeneous Fenton-like catalyst consisting of Cu-doped graphenelike catalysts (Cu-GCD NSs) was first synthesized by an enhanced carbothermal reduction of β-cyclodextrin (β-CD).The catalyst exhibits excellent Fenton-like catalytic activity for the degradation of various pollutants under neutral conditions,accompanied by low H_(2)O_(2)consumption.The results of structural characterization and theoretical calculations confirmed that the dual reaction centers (DRCs) were constructed on Cu-GCD NSs surface through C-O-Cu bonds supported on zero-valent copper species,which play a significant role in the high-performance Fenton-like reaction.The pollutants that served as electron donors were decomposed in the electron-poor carbon centers,whereas H_(2)O_(2)and dissolved oxygen obtained these electrons in the electron-rich Cu centers through C-O-Cu bonds,thereby producing more active species.This study demonstrates that the electrons of pollutants can be efficiently utilized in Fenton-like reactions by DRCs on the catalyst surface,which provides an effective strategy to improve Fenton-like reactivity and reduce H_(2)O_(2)consumption.

在NaCl非水离子液体中制备类石墨烯状氮硫共掺杂生物质碳材料来提高锂硫电池的动力学研究（英文）

本论文通过结构设计利用简单方法成功制备了一种二维N,S共掺杂类石墨烯纳米片复合结构,即利用NaCl非水离子液体的剥离作用使生物质剥离得到二维片层类石墨烯结构.这种新的非水离子液体剥离技术较其他的碳材料剥离技术具有环境友好性、低成本、安全无毒性等优势,有利于实现量化制备锂硫电池电极材料.该材料采用大自然中广泛存在的紫菜作为原料,其内部富含的氨基酸为原位掺杂N,S元素提供了可能性.二维结构的纳米片能够提供有效的导电性和电解液浸润性的网络结构,同时还能够有效地降低电池在充放电循环过程中导致的体积膨胀效应,最终实现一种高机械性能、优异电化学活性的电极在锂硫电池储能领域中的应用.

钴/氮共掺杂多孔类石墨烯催化剂的制备及其高效氧还原性能表征（英文）

本文通过纳米硅作为保护层结合高温热解得到一种新型钴/氮共掺杂多孔类石墨烯纳米碳材料氧还原催化剂(Co/N-GLC).结果显示, Co/N-GLC具有类似于石墨烯的碳纳米薄层结构,并展现出分级多孔(微孔/介孔)特性,其比表面积高达809 m^2g^(-1);此外, Co/N-GLC还拥有较高的吡啶氮和石墨氮含量.这些优异的特性使得Co/N-GLC在碱性介质中具有出色的氧还原活性,接近于商业Pt/C催化剂.同时,在锌空气电池测试中, Co/N-GLC具有接近Pt/C电极的放电性能和优异的稳定性,表明该催化剂有望替代贵金属催化剂,具有很好的应用前景.