Structural behavior and metallization of AsSbS_(3) at high pressure

The group V–VI semiconductor material getchellite (crystalline AsSbS_(3)) has garnered extensive attention due to itswonderful electronic and optical properties. The pressure engineering is one of the most effective methods to modulatecrystal structure and physical properties of semiconductor materials. In this study, the structural behavior, optical and electricalproperties of AsSbS_(3) under high pressure have been investigated systematically by in situ high-pressure experimentsfor the first time. The monoclinic structure of AsSbS_(3) remains stable up to 47.0 GPa without phase transition. The graduallattice contraction with increasing pressure results in a continuous narrowing of the bandgap then leads to pressure-inducedmetallization of AsSbS_(3) at 31.5 GPa. Our research presents a high-pressure strategy for tuning the crystal structure andphysical properties of AsSbS_(3) to expand its potential applications in electronic and optoelectronic fields.

3D printing of poly(ethyleneimine)-functionalized Mg-Al mixed metal oxide monoliths for direct air capture of CO_(2)

Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.

Advances in noble metal-modified g-C_(3)N_(4) heterostructures toward enhanced photocatalytic redox ability

The photocatalytic activity of catalysts depends on the energy-harvesting ability and the separation or transport of photogenerated carriers.The light absorption capacity of graphitic carbon nitride(g-C_(3)N_(4))-based composites can be enhanced by adjusting the surface plasmon resonance(SPR)of noble metal nanoparticles(e.g.,Cu,Au,and Pd)in the entire visible region.Adjustments can be carried out by varying the nanocomponents of the materials.The SPR of noble metals can enhance the local electromagnetic field and improve interband transition,and resonant energy transfer occurs from plasmonic dipoles to electron-hole pairs via near-field electromagnetic interactions.Thus,noble metals have emerged as relevant nanocomponents for g-C_(3)N_(4) used in CO_(2) photoreduction and water splitting.Herein,recent key advances in noble metals(either in single atom,cluster,or nanoparticle forms)and composite photocatalysts based on inorganic or organic nanocomponent-incorporated g-C_(3)N_(4) nanosheets are systematically discussed,including the applications of these photocatalysts,which exhibit improved photoinduced charge mobility in CO_(2) photoconversion and H2 production.Issues related to the different types of multi-nanocomponent heterostructures(involving Schottky junctions,Z-/S-scheme heterostructures,noble metals,and additional semiconductor nanocomponents)and the adjustment of dimensionality of heterostructures(by incorporating noble metal nanoplates on g-C_(3)N_(4) forming 2D/2D heterostructures)are explored.The current prospects and possible challenges of g-C_(3)N_(4) composite photocatalysts incorporated with noble metals(e.g.,Au,Pt,Pd,and Cu),particularly in water splitting,CO_(2) reduction,pollution degradation,and chemical conversion applications,are summarized.

Metallo-β-Lactamases:A Major Threat to Human Health

Antibiotic resistance is one of the most significant challenges facing global healthcare. Since the 1940s, antibiotics have been used to fight infections, initially with penicillin and subsequently with various derivatives including cephalosporins, carbapenams and monobactams. A common characteristic of these antibiotics is the four-memberedβ-lactam ring. Alarmingly, in recent years an increasing number of bacteria have become resistant to these antibiotics. A major strategy employed by these pathogens is to use Zn(II)-dependent enzymes, the metallo-β-lactamases (MBLs), which hydrolyse theβ-lactam ring. Clinically useful MBL inhibitors are not yet available. Consequently, MBLs remain a major threat to human health. In this review biochemical properties of MBLs are discussed, focusing in particular on the interactions between the enzymes and the functionally essential metal ions. The precise role(s) of these metal ions is still debated and may differ between different MBLs. However, since they are required for catalysis, their binding site may present an alternative target for inhibitor design.

Novel synthesis metal 3-alkylthiophene copolymer

Copolymer, regiorandom and regioregular poly （ 3-octylthiophene ）-co-poly （ 3-（ 2-ethyl-1- hexylthiophene））（P3OTIOT） was synthesized by a FeCl3-oxidation and GRIM （grignard method） approach. The structure and optical properties were verified by the Fourier transform infrared, ultraviolet visible spectroscopy, NMR （nuclear magnetic resonance ）, gel permeation chromatography （GPC） and photoluminescence （PL）. The results indicate that the band-gap energy of the regioregular HT P3OTEHT was lower than that of the regiorandom copolymer and both of them depict low band-gap energy, high photoluminescence quantum yield, excellent solubility and processability, and might be promising polymer materials for applications in polymer light-emitting diodes, light-emitting electrochemical cells and polymer solar cells, etc.

Ti_(3)C_(2)T_(x)超薄纳米片高效率去除废水中重金属的研究

通过刻蚀剥离法制备了Ti_(3)C_(2)T_(x)超薄纳米片,探究了其对废水中重金属离子的吸附特性。通过SEM、XRD、AFM、FT-IR、Raman对Ti_(3)C_(2)T_(x)超薄纳米片的形貌和结构进行了表征,通过ICP-MS对处理前后水体中重金属离子的含量进行了测试。结果表明剥离的Ti_(3)C_(2)T_(x)超薄纳米片表面含有结构缺陷和羟基,当水体中Cu(Ⅱ)、Pb(Ⅱ)、Cr(Ⅵ)初始浓度为50 mg/L时,47.5 mg Ti_(3)C_(2)T_(x)超薄纳米片对其的去除效率高达90%以上,尤其是对Pb(Ⅱ)的去除效率达到了98.81%,吸附性能远高于大孔树脂、硅藻土和活性炭等常见吸附试剂。在Na(Ⅰ)、Cu(Ⅱ)、Pb(Ⅱ)、Cr(Ⅵ)4种离子共存溶液中,Ti_(3)C_(2)T_(x)超薄纳米片对于Pb(Ⅱ)和Cr(Ⅵ)的去除依然可以达到92%以上。通过动力学和吸附等温拟合,Ti_(3)C_(2)T_(x)纳米片对Pb(Ⅱ)的吸附符合拟二级动力学模型和Langmuir等温模型,对Pb(Ⅱ)的最大吸附量和最低检出限分别为81.7 mg/g和0.0094 mg/L。Ti_(3)C_(2)T_(x)超薄纳米片对重金属离子的吸附特性在化学工业、食品加工的废水处理中具有良好的应用前景。

Spectroscopic Properties and Judd-Ofelt Theory Analysis of Er^(3+)-Doped Heavy Metal Oxyfluoride Silicate Glass

Er^(3+)-doped heavy metal oxyfluoride silicate glass was fabricated and characterized, and the absorption spectrum and fluorescence spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ω_t (t =2, 4, 6), spontaneous transition probability, fluorescence branching ratio and radiative lifetime of each energy levels for Er^(3+) were calculated by Judd-Ofelt theory, and stimulated emission cross-section of (()~4I_(13/2))→(()~4I_(15/2)) transition was calculated by McCumber theory. The results show that fluorescence full width at half maximum and stimulated emission cross-section of Er^(3+)-doped heavy metal oxyfluoride silicate glass are broad and large, respectively. Compared with other host glasses, the gain bandwidth property of Er^(3+)-doped heavy metal oxyfluoride silicate glass is close to those of tellurite and bismuth glasses, and has advantage over those of silicate, phosphate and germante glasses.

Ammonia Decomposition over Bimetallic Nitrides Supported on g-Al_2O_3

A series of monometallic nitrides and bimetallic nitrides were prepared by temperature-programmed reaction with NH3. The effects of Co, Ni and Fe additives and the synergic action between Fe, Co, Ni and Mo on the ammonia decomposition activity were investigated. TPR-MS, XRD were also carried out to obtain better insight into the structure of the bimetallic nitride. The results of ammonia decomposition activity show that bimetallic nitrides are more active than monometallic nitrides or bimetallic oxides.

A novel design of 3D carbon host for stable lithium metal anode

Rational design of porous conductive hosts with high electrical conductivity,large surface area,and adequate interior space is desirable to suppressing dendritic lithium growth and accommodating large volume change of lithium metal anode during the Li plating/stripping process.However,due to the conductive nature of the conductive hosts,Li is easily deposited directly on the top of the hosts,which hinders it from fully functioning.To circumvent the issue,in this study,we designed a novel porous carbon host with a gradient-pore-size structure based on one-dimensional(1D)carbon with different diameters.With this kind of host,stable cycling with high and stable Coulombic efficiency of~98%is achieved at 0.5 mA cm^(−2) with an areal capacity of 1 mAh cm^(−2) over 320 cycles.In contrast,the normal three-dimensional(3D)carbon nanotube host presents a moss-like Li morphology with wildly fluctuating Coulombic efficiency after 100 cycles.The results reveal that the unique gradient-pore-size structure of the 3D conductive host greatly improves the performance of lithium metal batteries.

Fabrication of Poly（y-glutamic acid）-coated Fe3O4 Magnetic Nanoparticles and Their Application in Heavy Metal Removal

In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erage size and specific surface area results reveal that 7-PGA/Fe304 MNPs （52.4 nm, 88.41 m2.g-1） have smaller particle size and larger specific surface area_ than Fe3O4 MNPs （62.0 nm, 76.83 mLg-1）. The y-PGA/Fe3O4 MNPs

Adsorption properties of a novel 3D graphene/MgO composite for heavy metal ions

A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscope(TEM),powder X-raydiffraction(XRD)and X-rayphotoelectron spectroscopy(XPS)were employed to characterize the prepared 3D graphene/MgO composite.The adsorption performance of some metal ions on 3D graphene/MgO was investigated.The results showed that the adsorption capacity was greater than 3D graphene and the maximum adsorption capacity at 25℃was found to be 358.96 mg/g,388.4 mg/g and 169.8 mg/g for Pb^2+,Cd^2+and Cu^2+,respectively.The adsorption kinetic conformed to the pseudo-second-order kinetic model and the adsorption isotherm was well described by Langmuir model.The thermodynamic constants revealed that the sorption process was endothermic and spontaneous in nature.Based on the results of the removal of heavy metal ions from metal smelting wastewater,it can be concluded that the prepared 3D graphene/MgO composite is an effective and potential adsorbent.

Fiber Traction Printing:A 3D Printing Method of Continuous Fiber Reinforced Metal Matrix Composite

A novel metal matrix composite freeform fabrication approach,fiber traction printing(FTP),is demonstrated through controlling the wetting behavior between fibers and the matrix.This process utilizes the fiber bundle to control the cross-sectional shape of the liquid metal,shaping it from circular to rectangular which is more precise.The FTP process could resolve manufacturing difficulties in the complex structure of continuous fiber reinforced metal matrix composites.The printing of the first layer monofilament is discussed in detail,and the effects of the fibrous coating thickness on the mechanical properties and microstructures of the composite are also investigated in this paper.The composite material prepared by the FTP process has a tensile strength of 235.2 MPa,which is close to that of composites fabricated by conventional processes.The complex structures are printed to demonstrate the advantages and innovations of this approach.Moreover,the FTP method is suited to other material systems with good wettability,such as modified carbon fiber,surfactants,and aluminum alloys.

NF_3 decomposition over some metal oxides in the absence of water

NF3 decomposition in the absence of water over Al2O3, Fe2O3, Co3O4 and NiO, and transition metal oxides （Fe203, CO3O4 and NiO） coated Al2O3 reagents was investigated. The results show that Al2O3 is an active reagent for NF3 decomposition with 100% conversion lasting for 8.5 h at 400 ℃. Fe203, Co3O4 and NiO coated Al2O3 reagents are superior to bare Al2O3, and 5%Co3O4/Al2O3 has a high reactivity with NF3 full conversion maintaining for 10.5 h. It is suggested that the presence of transition metal oxide is beneficial to the reactivity of Al2O3, and results in a significant enhancement in the fluorination of Al2O3.

A comparison study of alkali metal-doped g-C_3N_4 for visible-light photocatalytic hydrogen evolution

Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.

Metal–Organic Framework-Assisted Synthesis of Compact Fe_2O_3 Nanotubes in Co_3O_4 Host with Enhanced Lithium Storage Properties

Transition metal oxides are promising candidates for the high-capacity anode material in lithium-ion batteries.The electrochemical performance of transition metal oxides can be improved by constructing suitable composite architectures. Herein, we demonstrate a metal–organic framework(MOF)-assisted strategy for the synthesis of a hierarchical hybrid nanostructure composed of Fe_2O_3 nanotubes assembled in Co_3O_4 host. Starting from MOF composite precursors(Fe-based MOF encapsulated in a Cobased host matrix), a complex structure of Co_3O_4 host and engulfed Fe_2O_3 nanotubes was prepared by a simple annealing treatment in air. By virtue of their structural and compositional features, these hierarchical composite particles reveal enhanced lithium storage properties when employed as anodes for lithium-ion batteries.

Peroxymonosulfate activation by Mn_3O_4/metal-organic framework for degradation of refractory aqueous organic pollutant rhodamine B

An environmentally friendly Mn‐oxide‐supported metal‐organic framework(MOF),Mn3O4/ZIF‐8,was successfully prepared using a facile solvothermal method,with a formation mechanism proposed.The composite was characterized using X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,X‐ray photoelectron microscopy,and Fourier‐transform infrared spectroscopy.After characterization,the MOF was used to activate peroxymonosulfate(PMS)for degradation of the refractory pollutant rhodamine B(RhB)in water.The composite prepared at a0.5:1mass ratio of Mn3O4to ZIF‐8possessed the highest catalytic activity with negligible Mn leaching.The maximum RhB degradation of approximately98%was achieved at0.4g/L0.5‐Mn/ZIF‐120,0.3g/L PMS,and10mg/L initial RhB concentration at a reaction temperature of23°C.The RhB degradation followed first‐order kinetics and was accelerated with increased0.5‐Mn/ZIF‐120and PMS dosages,decreased initial RhB concentration,and increased reaction temperature.Moreover,quenching tests indicated that?OH was the predominant radical involved in the RhB degradation;the?OH mainly originated from SO4??and,hence,PMS.Mn3O4/ZIF‐8also displayed good reusability for RhB degradation in the presence of PMS over five runs,with a RhB degradation efficiency of more than96%and Mn leaching of less than5%for each run.Based on these findings,a RhB degradation mechanism was proposed.

In situ generation of Li_(3)N concentration gradient in 3D carbon-based lithium anodes towards highly-stable lithium metal batteries

The uncontrolled dendrite growth of lithium metal anodes(LMAs)caused by unstable anode/electrolyte interface and uneven lithium deposition have impeded the practical applications of lithium metal batteries(LMBs).Constructing a robust artificial solid electrolyte interphase(SEI)and regulating the lithium deposition behavior is an effective strategy to address these issues.Herein,a three-dimensional(3D)lithium anode with gradient Li_(3)N has been in-situ fabricated on carbon-based framework by thermal diffusion method(denoted as CC/Li/Li_(3)N).Density functional theory(DFT)calculations reveal that Li_(3)N can effectively promote the transport of Li^(+)due to the low energy barrier of Li^(+)diffusion.As expected,the Li_(3)N-rich conformal artificial SEI film can not only effectively stabilize the interface and avoid parasitic reactions,but also facilitate fast Li^(+)transport across the SEI layer.The anode matrix with uniformly distributed Li3N can enable homogenous deposition of Li,thus preventing Li dendrite propagation.Benefiting from these merits,the CC/Li/Li_(3)N anode achieves ultralong-term cycling for>1000 h at a current density of 2 m A cm^(-2)and dendrite-free Li deposition at an ultrahigh rate of 20 m A cm^(-2).Moreover,the full cells coupled with LiFePO4cathodes show extraordinary cycling stability for>300 cycles in liquidelectrolyte-based batteries and display a high-capacity retention of 96.7%after 100 cycles in solid-state cells,demonstrating the promising prospects for the practical applications of LMBs.

TiO_2-Supported Binary Metal Oxide Catalysts for Low-temperature Selective Catalytic Reduction of NO_x with NH_3

Binary metal oxide（MnOx-A/TiO2）catalysts were prepared by adding the second metal to manganese oxides supported on titanium dioxide（TiO2）,where,A indicates Fe2O3,WO3,MoO3,and Cr2O3.Their catalytic activity,N2 selectivity,and SO2 poisonous tolerance were investigated.The catalytic performance at low temperatures decreased in the following order：Mn-W/TiO2〉Mn-Fe/TiO2〉Mn-Cr/TiO2〉Mn-Mo/TiO2,whereas the N2 selectivity decreased in the order：Mn-Fe/TiO2〉Mn-W/TiO2〉Mn-Mo/TiO2〉Mn-Cr/TiO2.In the presence of 0.01%SO2 and 6%H2O,the NOx conversions in the presence of Mn-W/TiO2,Mn-Fe/TiO2,or Mn-Mo/TiO2 maintain 98.5%,95.8%and 94.2%, respectively,after 8 h at 120°C at GHSV 12600 h？ 1 .As effective promoters,WO3 and Fe2O3 can increase N2 selectivity and the resistance to SO2 of MnOx/TiO2 significantly.The Fourier transform infrared（FTIR）spectra of NH3 over WO3 show the presence of Lewis acid sites.The results suggest that WO3 is the best promoter of MnOx/TiO2,and Mn-W/TiO2 is one of the most active catalysts for the low temperature selective catalytic reduction of NO with NH3.

Plasmon Assisted Highly Efficient Visible Light Catalytic CO_(2) Reduction Over the Noble Metal Decorated Sr-Incorporated g-C_(3)N_(4)

The photocatalytic performance of g-C_(3)N_(4) for CO_(2) conversion is still inadequate by several shortfalls including the instability,insu cient solar light absorption and rapid charge carrier's recombination rate. To solve these problems,herein,noble metals(Pt and Au)decorated Sr-incorporated g-C_(3)N_(4) photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C_(3)N_(4) band gap from 2.7 to 2.54 eV,as evidenced by the UV–visible absorption spectra and the density functional theory results. The CO_(2) conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15 Sr-CN sample produced 48.55 and 74.54 μmol h-1 g-1 of CH_(4) and CO,respectively.These amounts are far greater than that produced by the Au/0.15 Sr-CN,0.15 Sr-CN,and CN samples. A high quantum e ciency of 2.92% is predicted for the Pt/0.15 Sr-CN sample. Further,the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO_(2) conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance e ect induced by noble metal nanoparticles.This work will provide a new approach for promoting the catalytic e ciency of g-C_(3)N_(4) for e cient solar fuel production.

Bottom-up lithium growth guided by Ag concentration gradient in 3D PVDF framework towards stable lithium metal anode

Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D framework remains a tough challenge.To achieve a uniform bottom-up Li growth,a scheme involving Ag concentration gradient in 3 D PVDF framework(C-Ag/PVDF)is proposed.Ag nanoparticles with a concentration gradient induce an interface activity gradient in the 3 D framework,and this gradient feature is still maintained during the cycle.As a result,the C-Ag/PVDF framework delivers a long lifespan over 1800 h at a current density of 1 mA cm^(-2) with a capacity of 1 mAh cm^(-2),and shows an ultra-long life(>1300 h)even at a high current density of 4 mA cm^(-2) with a capacity of 4 mAh cm^(-2).The advantage of concentration gradient provides further insights into the optimal design of the 3 D framework for stable Li metal anode.