MXene Ti3C2 decorated g-C3N4/ZnO photocatalysts with improved photocatalytic performance for CO2 reductionOA

Photocatalytic reduction of CO₂ is considered as a kind of promising technologies for solving the greenhouse effect. Herein, a novel hybrid structure of g-C₃N₄/ZnO/Ti₃C₂ photocatalysts was designed and fabricated to investigate their abilities for CO₂ reduction. As demonstration, heterojunction of g-C₃N₄/ZnO can improve photogenerated carriers’ separation, the addition of Ti₃C₂ fragments...     

Interfacial Electronic Modulation of Dual-Monodispersed Pt–Ni3S2 as Efficacious Bi-Functional Electrocatalysts for Concurrent H2 Evolution and Methanol Selective Oxidation

Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the development of electrochemicallydriven technologies for efficient hydrogen production and avoid CO₂ emission. Herein, the hetero-nanocrystals between monodispersed Pt(～ 2 nm) and Ni₃S₂(～ 9.6 nm) are constructed as active electrocatalysts through interfacial...     

Continuous dimethyl carbonate synthesis from CO2 and methanol over BixCe1-xOδ monoliths:Effect of bismuth doping on population of oxygen vacancies,activity,and reaction pathway

We evaluated bismuth doped cerium oxide catalysts for the continuous synthesis of dimethyl carbonate(DMC)from methanol and carbon dioxide in the absence of a dehydrating agent.Bi_xCe_1-xO_δnanocomposites of various compositions(x=0.06-0.24)were coated on a ceramic honeycomb and their structural and catalytic properties were examined.The incorporation of Bi species into the CeO₂ lattice facilitated controlling of the surface population of oxygen vacancies,which is shown to play a crucial role in the mechanism of this reaction and is an important parameter for the design of ceria-based catalysts.The DMC production rate of the Bi_xCe_1-xO_δ catalysts was found to be strongly enhanced with increasing Ov concentration.The concentration of oxygen vacancies exhibited a maximum for Bi_0.12Ce_0.88O_δ,which afforded the highest DMC production rate.Long-term tests showed stable activity and selectivity of this catalyst over 45 h on-stream at 140°C and a gas-hourly space velocity of 2,880 mL·g_cat^-1·h^-1.In-situ modulation excitation diffuse reflection Fourier transform infrared spectroscopy and first-principle calculations indicate that the DMC synthesis occurs through reaction of a bidentate carbonate intermediate with the activated methoxy(-OCH₃)species.The activation of C0₂ to form the bidentate carbonate intermediate on the oxygen vacancy sites is identified as highest energy barrier in the reaction pathway and thus is likely the rate-determining step.     

Bridging localized electron states of pyrite-type C0S2 cocatalyst for activated solar H2 evolution

The development of low-cost and high-active cocatalysts is one of the most significant links for photocatalytic water splitting.Herein,a novel strategy of electron delocalization modulation for transition metal sulfides has been developed by anion hybridization.P-modified CoS₂(CoS₂|P)nanocrystals were firstly fabricated via a gas-solid reaction and coupled with CdS nanorods to construct a composite catalyst for solar H2 evolution reaction(HER).The CdS/CoS₂|P catalyst shows an HER rate of 57.8 pmol h-1,which is 18 times that of the bare CdS,8 times that of the CdS/CoS2,and twice that of Pt/CdS.The reduced energy barrier and suppressed reverse reaction for HER on the catalyst have been predicted and explained by density functional theory(DFT)calculation.The underlying design strategy of novel cocatalysts by electron delocalization modulation may shed light on the rational development of other advanced catalysts for energy conversion.     

Oxidation behaviors of(Hf0.25Zr0.25Ta0.25Nb0.25)C and(Hf0.25Zr0.25Ta0.25Nb0.25)C-SiC at 1300-1500℃

In this work,high-entropy ceramics(Hf_0.25 Zr_0.25Ta_0.25Nb_0.25)C(HZTNC) and HZTNC doped with 20 vol%SiC(HZTNC-SiC) were fabricated by spark plasma sintering.Their oxidation behavior was investigated over the temperature range of 1300-1500℃ for up to 60 min.Both HZTNC and HZTNC-SiC exhibited good oxidation resistance,and their weight change as a function of oxidation time obeyed a parabolic law.Through XRD,microstructure observation,and elemental mapping analysis of the oxide layers,it was found that the formation of Nb₂ Zr₆ O₁₇,Hf₆ Ta₂ O₁₇,and(Ta,Nb)₂ O₅ mixed-oxide layers effectively protected the matrix from further oxidation.Microcracks began to appear on the oxide layer of HZTNC at high temperatures after 60 min of oxidation.However,the addition of SiC in HZTNC suppressed these microcracks at high temperatures due to the active oxidation of SiC.Compared with the oxides formed on HZTNC,the additional formation of Hf(Zr)SiO₄ on HZTNC-SiC could further improve its oxidation resistance over HZTNC ceramics.     

Freestanding nanosheets of 1T-2H hybrid MoS2 as electrodes for efficient sodium storage

Molybdenum disulfide(MoS₂) is a promising electrode material for sodium-ion batteries as it offers a large capacity through a distinct conversion reaction.However,the electrochemical potential of MoS₂ is often restrained by the poor conductivity as the dominant 2 H phase is a semiconductor while the metallic1 T phase is thermodynamically unstable.In this work,we report a hybrid design and material preparation of freestanding nanosheets of MoS₂ composed of both 1 T and 2 H phases based on mild hydrothermal reaction.The introduction of the metallic 1 T-MoS₂ phase into 2 H-MoS₂ and their intimate hybridization enable a significant improvement in electronic conductivity,while the freestanding architecture avoids possible electrochemical aggregation.When used as electrodes for sodium storage,such a hybrid MoS₂ affords a high capacity of~500 mA h g^-1 at 0.5 A g^-1 after 300 cycles,and retains capacity of~200 mA h g^-1 at a high current rate of 4 A g^-1,thus demonstrating their potential in high-performance battery applications.     

NiCo2S4/N microspheres grown on N,S co-doped reduced graphene oxide as an efficient bifunctional electrocatalyst for overall water splitting in alkaline and neutral pH

It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo₂S₄/N,S co-doped reduced graphene oxide(NCS/NS-rGO)electrocatalyst for water splitting,in which NCS microspheres are composed of one-dimentional(1D)nanorods grown homogeneously on the surface of NS-rGOs).The synergetic effect,abundant active sites,and hybridization of NCS/NS-rGO endow their outstanding electrocatalytic performance for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in both alkaline and neutral conditions.Furthermore,NCS/NS-rGO employed as both anode and cathode in a two-electrode alkaline and neutral system electrolyzers deliver 10 mA/cm² with the low cell voltage of 1.58 V in alkaline and 1.91 V in neutral condition.These results illustrate the rational design of carbon-supported nickel-cobalt based bifunctional materials for practical water splitting over a wide pH range.     

Multifunctional,Sustainable, and Biological Non-Ureolytic Self-Healing Systems for Cement-Based MaterialsOA

Microbially induced calcium carbonate(Ca CO₃) precipitation(MICP) has been investigated as a sustainable alternative to conventional concrete remediation methods for improving the mechanical properties and durability of concrete structures. To date, urea-dependent MICP is the most widely employed MICP pathway in biological self-healing concrete research as its use has resulted in efficient Ca CO₃ precipitation rates. NH₃ is a byproduct of ureolysis, and can be ha...     

Effect of sintering temperature on the chemical bonding,electronic structure and electrical transport properties of β-Ga1.9Fe0.1O3 compounds

A model system,which is based on iron(Fe)doped gallium oxide(Ga₂O₃)(Ga_1.9Fe_0.1O₃),has been considered to elucidate the combined effect of transition-metal ion doping and processing temperature on the chemistry,local structure and chemical bonding,and electrical transport properties of a wide band gap oxide(Ga₂O₃).The Ga_1.9Fe_0.1O₃ compounds were synthesized using standard high-temperature solid state reaction method.The effect of processing conditions in terms of different calcination and sintering environments on the structural and electrical properties of Ga_1.9Fe_0.1O₃ compounds is studied in detail.Structural characterization by Raman spectroscopy revealed that Ga_1.9Fe_0.1O₃ compounds exhibit monoclinic crystal symmetry,which is quite similar to the intrinsic parental crystal structure,though Fedoping induces lattice strain.Sintering temperature(T_sint)which was varied in the range of 900-1200℃,has significant impact on the structure,chemical bonding,and electrical properties of Ga_1.9Fe_0.1O₃ compounds.Raman spectroscopic measurements indicate the proper densification of the Ga_1.9Fe_0.1O₃ compounds achieved through complete Fe diffusion into the parent Ga₂O₃ lattice which is evident at the highest sintering temperature.The X-ray photoelectron spectroscopy validates the chemical states of the constituent elements in Ga_1.9Fe_0.1O₃ compounds.The electrical properties of Ga_1.9Fe_0.1O₃ fully controlled by T_sint,which governed the grain size and microstructural evolution.The temperature and frequency dependent electrical measurements demonstrated the salient features of the Fe doped Ga₂O₃ compounds.The activation energy determined from Arrhenius equation is 0.5 e V.The results demonstrate that control over structure,morphology,chemistry and electrical properties of the Ga_1.9Fe_0.1O₃ compounds can be achieved by optimizing T_sint.     

Ru(bpy)32+-sensitized{001}facets LiCoO2 nanosheets catalyzed CO2 reduction reaction with 100% carbonaceous products

Photosensitized heterogeneous CO₂ reduction(PHCR)has emerged as a promising means to convert CO₂ into valuable chemicals,however,challenged by the relatively low carbonaceous product selectivity caused by the competing hydrogen evolution reaction(HER).Here,we report a PHCR system that couples Ru(bpy)32+photosensitizer with{001}faceted LiCoO₂ nanosheets photocatalyst to simultaneously yield 21.2 and 722μmol·g^-1·h^-1 of CO,and 4.42 and 108μmol·g^-1·h^-1 of CH4 under the visible light and the simulated sunlight irradiations,respectively,with completely suppressed HER.The experimental and theoretical studies reveal that the favored CO₂ adsorption on the exposed Li sites on{001}faceted LiCoO₂ surface is responsible for the completely suppressed HER.     

A Planar 4-Bit Reconfigurable Antenna Array Based on the Design Philosophy of Information MetasurfacesOA

Inspired by the design philosophy of information metasurfaces based on the digital coding concept,a planar 4-bit reconfigurable antenna array with low profile of 0.15λ₀(where λ₀ is the free-space wavelength)is presented.The array is based on a digital coding radiation element consisting of a 1-bit magnetoelectric(ME) dipole and a miniaturized reflection-type phase shifter(RTPS).The proposed 1-bit ME dipole can provide two digital states of "0" and "1"(with 0° and 180° phase...     

H2O2的高效电合成及其电Fenton在难降解有机物降解中的应用(英文)

Hydrogen peroxide(H₂O₂) in situ electrosynthesis by O₂ reduction reaction is a promising alternative to the conventional Fenton treatment of refractory wastewater.However,O₂ mass transfer limitation,cathodic catalyst selectivity,and electron transfer in O₂ reduction remain major engineering obstacles.Here,we have proposed a systematic solution for efficient H₂O₂ generation and its electro-Fenton(EF)application for refra...     

Internal Polarization Field Induced Hydroxyl Spillover Effect for Industrial Water Splitting Electrolyzers

The formation of multiple oxygen intermediates supporting efficient oxygen evolution reaction(OER) are affinitive with hydroxyl adsorption. However, ability of the catalyst to capture hydroxyl and maintain the continuous supply at active sits remains a tremendous challenge. Herein, an affordable Ni₂P/FeP₂ heterostructure is presented to form the internal polarization field(IPF), arising hydroxyl spillover(HOSo) during OER. Facilitated by IPF, the oriented HOSo from FeP_...     

Heterogeneous lamellar-edged Fe-Ni(OH)2/Ni3S2 nanoarray for efficient and stable seawater oxidation

Development of efficient non-precious catalysts for seawater electrolysis is of great significance but challenging due to the sluggish kinetics of oxygen evolution reaction(OER)and the impairment of chlorine electrochemistry at anode.Herein,we report a heterostructure of Ni₃S₂nanoarray with secondary Fe-Ni(OH)₂lamellar edges that exposes abundant active sites towards seawater oxidation.The resultant Fe-Ni(OH)₂/Ni₃S₂nanoarray works directly as a free-standing anodic electrode in alkaline artificial seawater.It only requires an overpotential of 269 mV to afford a current density of 10 mA·cm^-2and the Tafel slope is as low as 46 m V·dec^-1.The 27-hour chronopotentiometry operated at high current density of 100 mA·cm^-2shows negligible deterioration,suggesting good stability of the Fe-Ni(OH)₂/Ni₃S₂@NF electrode.Faraday efficiency for oxygen evolution is up to?95%,revealing decent selectivity of the catalyst in saline water.Such desirable catalytic performance could be benefitted from the introduction of Fe activator and the heterostructure that offers massive active and selective sites.The density functional theory(DFT)calculations indicate that the OER has lower theoretical overpotential than Cl₂ evolution reaction in Fe sites,which is contrary to that of Ni sites.The experimental and theoretical study provides a strong support for the rational design of high-performance Fe-based electrodes for industrial seawater electrolysis.     

Light-responsive color switching of self-doped TiO2-x/WO3·0.33H2O hetero-nanoparticles for highly efficient rewritable paper

Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications.However,light-responsive color switching materials are mainly limited to organic molecules.The synthesis of inorganic counterparts has remained a significant challenge because of their slow light response and poor reversibility.Here,we report a seeded growth strategy for the synthesis of TiO_2-x/WO₃·0.33H₂Ohetero-nanoparticles(HNPs)with networked wire-like structure of?10 nm in diameters that enable the highly reversible light-responsive color switching properties.For the TiO_2-x/WO₃·0.33H₂OHNPs,T P species self-doped in TiO_2-xnanoparticles(NPs)act as efficient sacrificial electron donors(SEDs)and Ti-O-W linkages formed between TiO2-x and WO30.33H2O NPs ensure the nanoscale interfacial contact,endowing the HNPs enhanced photoreductive activity and efficient interfacial charge transfer upon ultraviolet(UV)illumination to achieve highly efficient color switching.The TiO_2-x/WO₃·0.33H₂OHNPs exhibits rapid light response(<15 s)and long reversible color switching cycles(>180 times).We further demonstrate the applications of TiO_2-x/WO₃·0.33H₂O HNPs in ink-free,light-printable rewritable paper that can be written on freehand or printed on through a photomask using UV light.This work opens an avenue for designing inorganic light-responsive color switching nanomaterials and their smart applications.     

High mass loading Ni4Co1-OH@CuO core-shell nanowire arrays obtained by electrochemical reconstruction for alkaline energy storage

The design of three-dimensional(30)core-shell hetercistructures is an efficient method to achieve high mass specific capacity of electroactive materials under high mass loading.In this work,porous Ni₄Co1-0H nanosheets with a mass loading of 7.7 mg·cm^-2 are obtained by using Ni₄Cor(NO₃)₂(0H)₄ supported on the CuO nanowires as precursors via an unavoidable electrochemically induced phase reconstruction.During the electrochemical reconstruction process,the N03-anions in Ni₄Cor(N0₃)₂(0H)₄ are easily replaced by OH-anions in the electrolyte.The phase reconstruction is accompanied by the decrease of ionic diffusion.:resistance and the increase of pore volume,and the shift of binding energy.The obtained Ni4Co1-0H nanosheets show a high:mass specific capacity of 363.6 mAh·g^-1 at 5 mA·cm^-2.The as-fabricated alkaline hybrid supercapacitor and Ni-Zn battery deliver high energy density of 293.1 and 604.9 Wh·kg^-1,respectively,indicating.excellent alkaline energy storage performance.     

Structural and Physical Property Analysis of ZnO-SnO2—In2O3—Ga2O3 Quaternary Transparent Conducting Oxide System

The increasing demand in the diverse device applications of transparent conducting oxides（TCOs） requires synthesis of new TCOs of n- or p-type conductivity.This article is about materials engineering of ZnO—SnO₂—ln₂O₃—Ga₂O₃ to synthesize powders of the quaternary compound Zn_2-xSn_1-xJn_xGa_xO_4-δ in the stoichiometry of x = 0.2,0.3,and 0.4 by solid state reaction at 1275℃.Lattice parameters were determined by X-ray diffraction（XRD） technique and solubility of ln³⁺ and Ga³⁺ in spinel Zn₂SnO₄ was found at 1275℃.The solubility limit of ln³⁺ and Ga³⁺ in Zn₂SnO₄ is found at below x = 0.4.The optical transmittance approximated by the UV—Vis reflectance spectra showed excellent characteristics while optical band gap was consistent across 3.2 eV with slight decrease along increasing x value.Carrier mobility of the species was considerably higher than the older versions of zinc stannate spinel co-substitutions whereas the carrier concentrations were moderate.     

Green synthesis of Au@WSe2 hybrid nanostructures with the enhanced peroxidase-like activity for sensitive colorimetric detection of glucose

We report a colorimetric method for glucose detection based on Au nanoparticle-decorated WSe₂(Au@WSe₂)hybrid nanostructures.These hybrid structures are easily synthesized by simply stirring HAuCl₄ precursor with WSe₂ nanosheets in aqueous solution.Owing to strong synergistic catalytic effects of Au nanoparticles and WSe₂ nanosheets,the Au@WSe₂ hybrid nanostructures exhibit enhanced peroxidase-like activity(about 2-fold higher compared to WSe₂ nanosheets alone)for 3,3',5,5'-tetramethylbenzidine oxidation by H₂O₂.Based on the highly catalytical property,the colorimetric method for glucose detection is established by coupling glucose oxidase(GOx).The detection limit of glucose is 3.66 pM.Moreover,the proposed colorimetric method is applicable to glucose detection in serum samples and is promising for applications in biomedical fields.     

Enhancement of output power density in a modified polytetrafluoroethylene surface using a sequential O2/Ar plasma etching for triboelectric nanogenerator applications

In this work,the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene(PTFE)triboelectric nanogenerator(TENG).Enhancing surface area by a powerful O₂ and Ar bipolar pulse plasma etching without the use of CF₄ gas has been demonstrated for the first time.TENG with modified surface PTFE using a sequential two-step O₂/Ar plasma has a superior power density of 9.9 W·m^-2,which is almost thirty times higher than that of a pristine PTFE TENG.The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O₂/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG.The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),and X-ray photoelectron spectroscopy(XPS).The correlation of surface morphology,chemical structure,and TENG performance was elucidated.In addition,the applications of mechanical energy harvesting for lighting,charging capacitors,keyboard sensing and operating a portable calculator were demonstrated.     

Etching-Induced Surface Reconstruction of NiMoO4 for Oxygen Evolution Reaction

Rational reconstruction of oxygen evolution reaction(OER) precatalysts and performance index of OER catalysts are crucial but still challenging for universal water electrolysis. Herein, we develop a double-cation etching strategy to tailor the electronic structure of NiMoO₄, where the prepared NiMoO₄ nanorods etched by H₂O₂ reconstruct their surface with abundant cation deficiencies and lattice distortion. Calculation results reveal that the double cat...