Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β...Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.展开更多
Ti-10V-2Fe-3Al alloy with fine-grainedβphases was fabricated by friction stir processing with opti-mized processing parameters.The superplastic behavior of the specimens was investigated by tensile deformation at dif...Ti-10V-2Fe-3Al alloy with fine-grainedβphases was fabricated by friction stir processing with opti-mized processing parameters.The superplastic behavior of the specimens was investigated by tensile deformation at different strain rates and temperatures,and an optimal superplastic elongation of 634%was achieved at 700℃ and 3×10^(-4)/s.An annealing treatment at 650℃ for 60 min showed a mi-crostructure withαprecipitates distributed in theβmatrix in the friction stir specimen.Such pre-heat treatment improves the superplasticity of the specimen,achieving an elongation of up to 807%at 750℃ and 3×10^(-4)/s.The influences of tensile temperatures and strain rates on the microstructural evolution,such as grain size variation,grain morphology,and phase transformations,were discussed.The super-plastic deformation behavior of fine-grained Ti-10V-2Fe-3Al alloy is controlled by grain boundary sliding and accompanied by dynamic phase transformation and recrystallization.展开更多
Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3...Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3)N_(4)(N,S-g-C_(3)N_(4))is elaborately designed on the basis of theoretical predictions of first-principle density functional theory(DFT).The calculated Gibbs free energy of adsorbed hydrogen(ΔGH∗)for N,S-g-C_(3)N_(4) at the N-doping active sites is extremely close to zero(0.01 eV).Inspired by the theoretical predictions,the N,S-g-C_(3)N_(4) is successfully fabricated through ammonia-rich pyrolysis synthesis strategy,in which ammonia is in-situ obtained by pyrolyzing melamine.Subsequent characterizations indicate that the N,S-g-C_(3)N_(4) possesses high specific surface area,outstanding light utilization,good hydrophilicity,and efficient carrier transfer efficiency.Consequently,the N,S-g-C_(3)N_(4) displays an extremely high H2 evolution rate of 8269.9μmol g−1 h−1,achieves an apparent quantum efficiency(AQE)of 3.24%,and also possesses outsatnding durability.Theoretical calculations further demonstrate that N and S dopants can not only introduce doping energy level to reduce the band gap,but also induce charge redistribution to facilitate hydrogen adsorption,thus promoting the photocatalytic HER process.Moreover,femtosecond transient absorption(fs-TA)spectroscopy further corroborates the efficient photogenerated carrier transport of N,S-g-C_(3)N_(4).This research highlights a promising and reliable strategy to achieve superior photocatalytic activity,and exhibits significant guidance for precise designing high-efficiency photocatalysts.展开更多
Emerging contaminants in water sources present serious environmental and health risks,creating an urgent need for efficient and reliable treatment strategies.Photocatalytic advanced oxidation processes(AOPs)provide ra...Emerging contaminants in water sources present serious environmental and health risks,creating an urgent need for efficient and reliable treatment strategies.Photocatalytic advanced oxidation processes(AOPs)provide rapid reaction rates and strong oxidation capabilities,however,comprehensive evaluations of wastewater treatment,including degradation pathways,toxicity assessments and mechanistic insights,remain underexplored in the literature.This study presents novel S-scheme Mn_(0.5)Cd_(0.5)S/In_(2)S_(3)(MCS/IS)photocatalysts for efficient degradation of antibiotic pollutants,with a particular focus on tetracycline hydrochloride(TCH).The optimized MCS/IS photocatalyst demonstrates exceptional degradation efficiency and robust resistance to inorganic anions.Additionally,a continuous-flow wastewater treatment system,using an MCS/IS membrane,demonstrates outstanding stability in TCH photodegradation.Utilizing response surface methodology and Fukui function analysis,the effects of various parameters on photocatalytic degradation rates,along with the associated pathways and intermediate products,have been thoroughly investigated.Toxicity assessments confirm the environmental safety of the treated effluents.Mechanistic studies show that the S-scheme heterojunction in the MCS/IS photocatalyst improves electron-hole separation,thereby enhancing photocatalytic performance.It is expected that this study will serve as a model for advancing the removal of emerging contaminants,further enhancing photocatalytic AOPs as sustainable water purification technologies.展开更多
Zn-Al eutectoid alloy(ZA22)has ultra-high damping property,but its mechanical properties are still relatively low.In order to simultaneously improve the tensile strength and plasticity,a novel Al matrix composite inoc...Zn-Al eutectoid alloy(ZA22)has ultra-high damping property,but its mechanical properties are still relatively low.In order to simultaneously improve the tensile strength and plasticity,a novel Al matrix composite inoculant containing in-situ formed Al_(2)O_(3) and Al3Zr particles was designed and used to reinforce the ZA22 alloy.The microstructure of the ZA22 alloy was significantly refined.Fine Al_(2)O_(3) particles were uniformly distributed in theαphase and the lamellar eutectoid structure,whereas Al3Zr particles were distributed in theαphase and at theα/ηinterface.Property tests showed that the tensile mechanical properties of the reinforced ZA22 alloys were significantly improved.The maximum tensile strength and elongation reached 355 MPa and 7.62%,which were 1.50 and 1.89 times those of the original ZA22 alloy,respectively.The increase in mechanical properties is attributed to the multiple strengthening and toughening factors constructed in the refined microstructure.展开更多
An Al_(2)O_(3)/Al-Cu-Mn composite was fabricated using a combination of ball milling and liquid-solid reaction,with a nominal composition of Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3).The composite contains reinforcement particle...An Al_(2)O_(3)/Al-Cu-Mn composite was fabricated using a combination of ball milling and liquid-solid reaction,with a nominal composition of Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3).The composite contains reinforcement particles,including nano-sizedθ’and T(Al_(20)Cu_(2)Mn_(3))particles after T6 heat treatment,as well as in-situ synthesized nano-sizedγ-Al_(2)O_(3)particles.Tensile tests of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite and the Al-4Cu-0.5Mn base alloy after T6 treatment were carried out at room temperature and elevated temperatures(200°C,300°C,and 400°C).Compared with the base alloy,the yield strength of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite after T6 treatment increases significantly from 187 MPa to 263 MPa at room temperature.Simultaneously,at elevated temperatures,the yield strength is also enhanced,with a yield strength of 52 MPa at 400°C for this composite.The in-situ fabricatedγ-Al_(2)O_(3)particles,mainly distributed along the grain boundaries,are supposed to play the main strengthening role,especially at high temperatures.This work acts as a reference for designing composites for high-temperature applications.展开更多
Serial-parallel manipulators are of great interest to academic community in recent years,especially those composed of classical parallel mechanisms.There have been many studies around 2(3RPS)and 2(3SPR)S-PMs,but unfor...Serial-parallel manipulators are of great interest to academic community in recent years,especially those composed of classical parallel mechanisms.There have been many studies around 2(3RPS)and 2(3SPR)S-PMs,but unfortunately their inverse kinematics have not yet been resolved.This paper discovers that the unknown kinematic parameters of middle platform are responsible for the unresolvable of inverse kinematics,meanwhile the unknown kinematic parameters of middle platform also have huge coupling relationships.Therefore,to break through this challenges,the huge coupling relationships are decoupled layer by layer,the kinematic parameters of middle platform are solved by combining Sylvester's elimination method,and the inverse displacements of 2(3RPS)and 2(3SPR)S-PMs are obtained subsequently.This paper not only solves the inverse kinematics of classical 2(3RPS)and 2(3SPR)S-PMs,but also reveals the essence of the inverse kinematics of general(3-DOF)+(3-DOF)6-DOF S-PMs and proposes a corresponding solution.展开更多
The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as ...The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as a high-strength substrate to support fast-ion-conducting polymer-in-salt(PIS)solid-state electrolytes,aiming to suppress lithium dendrite growth and improve full-cell performance.The Al_(2)O_(3)coating layer not only refines the wettability of polyimide porous film to PIS,but also performs as a high modulus protective layer to suppress the growth of lithium dendrites.The resulting PI/AO@PIS exhibits a small thickness of only 35μm with an outstanding tensile strength of 11.3 MPa and Young's modulus of 537.6 MPa.In addition,the PI/AO@PIS delivers a high ionic conductivity of 0.1 m S/cm at 25°C.As a result,the PI/AO@PIS enables symmetric Li cells to achieve exceptional cyclability for over 1000 h at 0.1 m A/cm2without noticeable lithium dendrite formation.Moreover,the PI/AO@PIS-based LiFePO4||Li full cells demonstrate outstanding rate performance(125.7 m Ah/g at 5 C)and impressive cycling stability(96.1%capacity retention at 1 C after 200 cycles).This work highlights the efficacy of enhancing the mechanical properties of polymer matrices and extending cell performance through the incorporation of a dense inorganic interface layer.展开更多
Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)thr...Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)through the high-temperature solid-state spontaneous crystallization method.Different from the cubicα-Pb_(3)P_(2)S_(8),theβ-Pb_(3)P_(2)S_(8)crystallizes in the orthorhombic Pbcn space group.Notably,β-Pb_(3)P_(2)S_(8)shows a large band gap of 2.37 e V in lead-based chalcogenides,wide infrared transparent window(2.5-15μm),and excellent thermal stability.Importantly,the experimental birefringence shows the largest value of0.26@550 nm in chalcogenides,even larger than the commercialized oxide materials.The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb^(2+)and S^(2-)in the[Pb S_n]polyhedrons.Meanwhile,the parallelly arranged polyhedral layers could improve the structural anisotropic.Therefore,this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.展开更多
Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
β-Sialon has emerged as a promising material for enhancing the service life of Al_(2)O_(3)-C refractories due to its excellent physicochemical properties.The impact of varying concentrations of nanometer Al/Si alloy ...β-Sialon has emerged as a promising material for enhancing the service life of Al_(2)O_(3)-C refractories due to its excellent physicochemical properties.The impact of varying concentrations of nanometer Al/Si alloy on the in-situ synthesis of β-Sialon within Al_(2)O_(3)-C refractory materials,as well as its oxidation behavior,was investigated.The findings indicate that the presence of Al/Si alloy promotes the formation of AlN and SiC whiskers at 1300℃,which subsequently facilitate the production of plate-like β-Sialon at 1500℃.Density functional theory analysis reveals that the(020)crystal plane of β-Sialon exhibits the lowest adsorption energy for Al2O and AlO molecules under the influence of iron atoms,suggesting a solid-liquid-vapor growth mechanism for β-Sialon formation.The introduction of these ceramic phases significantly enhances the mechanical properties of Al_(2)O_(3)-C refractories.Specifically,the addition of 6 wt.%Al/Si alloy yielded specimens with the highest cold modulus of rupture and cold crushing strength at 1500℃,achieving values of 35.2 and 127.5 MPa,respectively--representing increases of 40.1%and 37.4%.Furthermore,during high-temperature oxidation,the formation of plate-like β-Sialon leads to the development of a dense protective layer on the surface.This impedes the diffusion pathways of oxygen and consequently enhances the oxidation resistance of the refractory.展开更多
Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/...Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/BiFeO_(3)(AAS/BFO),for photocatalytic degradation of ciprofloxacin from water.Experimental results verified the enhancement of combining heterostructure piezoelectric polarization effect,which promotes efficient migration and separation of photogenerated carriers due to the localized surface plasmon resonance effect of Ag nanoparticles.Additionally,the introduction of Ag_(2)S constructs a new heterostructure,that enhances the electron transport rate and improves the separation efficiency on electron-hole pairs.Under ultrasonic stimulation and visible light irradiation,the degradation efficiencies of 15%-AAS/BFO towards ciprofloxacin,methyl orange and methylene blue are significantly enhanced compared to pure BFO fibers.The demonstrated AAS/BFO material based on the synergistic piezoelectric effect and plasmon heterostructure shows potential in efficient organic pollutants water treatment and transforming mechanical energy into chemical energy.展开更多
The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonizatio...The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.展开更多
Metal-ceramic composites combine the excellent properties of metals and ceramics,which have high strength,stability,and corrosion re-sistance.Al_(2)O_(3)/FeCo composites have been proven to be useful in ap-plications ...Metal-ceramic composites combine the excellent properties of metals and ceramics,which have high strength,stability,and corrosion re-sistance.Al_(2)O_(3)/FeCo composites have been proven to be useful in ap-plications such as catalysts,mi-crowave absorption materials,and enhanced permeability dielectric.The understanding of the mechani-cal properties and dynamics at the atomic scale of the Al_(2)O_(3)/FeCo in-terface can promote the design and exploitment of metal-ceramic composites.In this work,we have obtained Young’s modulus and diffusion coefficient of the Al_(2)O_(3)/FeCo interface using molecular dynamics simulation,elucidated the structural characteristics of the Al_(2)O_(3)/FeCo interface at the atomic scale,and investigated the impact of atomic magnetism and the exter-nal magnetic field on the interface.Simulated results show that Young’s modulus of the Al_(2)O_(3)/FeCo interface is significantly improved compared with pure Al_(2)O_(3)and FeCo alloy at room and high temperatures.When the atomic magnetism and the external magnetic field are applied,Young’s modulus of the Al_(2)O_(3)/FeCo interface further increases to 612 GPa at 300 K and 602 GPa at 500 K.Moreover,the average density,diffusion coefficient,and radial distri-bution function are found to be modified substantially.This study will shed light on the atom-istic investigations of the metal-ceramic composites.展开更多
Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries(RMBs).Herein,a new non-nucleophilic mononuclear electrolyte was developed and its electro...Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries(RMBs).Herein,a new non-nucleophilic mononuclear electrolyte was developed and its electrochemical active species was identified as[Mg(DME)_(3)][GaCl_(4)]_(2) through single-crystal X-ray diffraction analysis.The as-synthesized Mg(GaCl_(4))_(2)-IL-DME electrolyte could achieve a high ionic conductivity(9.85 m S cm^(-1)),good anodic stability(2.9 V vs.Mg/Mg^(2+)),and highly reversible Mg plating/stripping.The remarkable electrochemical performance should be attributed to the in-situ formation of Mg^(2+)-conducting Ga_(5)Mg_(2)alloy layer at the Mg/electrolyte interface during electrochemical cycling,which not only efficiently protects the Mg anode from passivation,but also allows for rapid Mg-ion transport.Significantly,the Mg(GaCl_(4))_(2)-IL-DME electrolyte showed excellent compatibility with both conversion and intercalation cathodes.The Mg/S batteries with Mg(Ga Cl_(4))_(2)-IL-DME electrolyte and KB/S cathode showed a high specific capacity of 839 m Ah g^(-1)after 50 cycles at 0.1 C with the Coulombic efficiency of~100%.Moreover,the assembled Mg|Mo_6 S_8 batteries delivered a reversible discharge capacity of 85 m Ah g^(-1)after 120 cycles at 0.2 C.This work provides a universal electrolyte for the realization of high-performance and practical RMBs,especially Mg/S batteries.展开更多
基金Project supported in part by the Science and Technology Development Plan Project of Jilin Province, China (Grant No. YDZJ202303CGZH022)the National Key Research and Development Program of China (Grant No. 2024YFE0205300)+1 种基金the National Natural Science Foundation of China (Grant No. 62471504)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University) (Grant No. OEMT-2023KF-05)。
文摘Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.
基金financially supported by the National Natural Science Foundation of China(No.52105373)the China Scholarship Council(No.202106020094).
文摘Ti-10V-2Fe-3Al alloy with fine-grainedβphases was fabricated by friction stir processing with opti-mized processing parameters.The superplastic behavior of the specimens was investigated by tensile deformation at different strain rates and temperatures,and an optimal superplastic elongation of 634%was achieved at 700℃ and 3×10^(-4)/s.An annealing treatment at 650℃ for 60 min showed a mi-crostructure withαprecipitates distributed in theβmatrix in the friction stir specimen.Such pre-heat treatment improves the superplasticity of the specimen,achieving an elongation of up to 807%at 750℃ and 3×10^(-4)/s.The influences of tensile temperatures and strain rates on the microstructural evolution,such as grain size variation,grain morphology,and phase transformations,were discussed.The super-plastic deformation behavior of fine-grained Ti-10V-2Fe-3Al alloy is controlled by grain boundary sliding and accompanied by dynamic phase transformation and recrystallization.
基金supported by the National Natural Science Foun-dation of China(No.62004143)the Key R&D Program of Hubei Province(No.2022BAA084)the Natural Science Foundation of Hubei Province(No.2021CFB133).
文摘Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3)N_(4)(N,S-g-C_(3)N_(4))is elaborately designed on the basis of theoretical predictions of first-principle density functional theory(DFT).The calculated Gibbs free energy of adsorbed hydrogen(ΔGH∗)for N,S-g-C_(3)N_(4) at the N-doping active sites is extremely close to zero(0.01 eV).Inspired by the theoretical predictions,the N,S-g-C_(3)N_(4) is successfully fabricated through ammonia-rich pyrolysis synthesis strategy,in which ammonia is in-situ obtained by pyrolyzing melamine.Subsequent characterizations indicate that the N,S-g-C_(3)N_(4) possesses high specific surface area,outstanding light utilization,good hydrophilicity,and efficient carrier transfer efficiency.Consequently,the N,S-g-C_(3)N_(4) displays an extremely high H2 evolution rate of 8269.9μmol g−1 h−1,achieves an apparent quantum efficiency(AQE)of 3.24%,and also possesses outsatnding durability.Theoretical calculations further demonstrate that N and S dopants can not only introduce doping energy level to reduce the band gap,but also induce charge redistribution to facilitate hydrogen adsorption,thus promoting the photocatalytic HER process.Moreover,femtosecond transient absorption(fs-TA)spectroscopy further corroborates the efficient photogenerated carrier transport of N,S-g-C_(3)N_(4).This research highlights a promising and reliable strategy to achieve superior photocatalytic activity,and exhibits significant guidance for precise designing high-efficiency photocatalysts.
文摘Emerging contaminants in water sources present serious environmental and health risks,creating an urgent need for efficient and reliable treatment strategies.Photocatalytic advanced oxidation processes(AOPs)provide rapid reaction rates and strong oxidation capabilities,however,comprehensive evaluations of wastewater treatment,including degradation pathways,toxicity assessments and mechanistic insights,remain underexplored in the literature.This study presents novel S-scheme Mn_(0.5)Cd_(0.5)S/In_(2)S_(3)(MCS/IS)photocatalysts for efficient degradation of antibiotic pollutants,with a particular focus on tetracycline hydrochloride(TCH).The optimized MCS/IS photocatalyst demonstrates exceptional degradation efficiency and robust resistance to inorganic anions.Additionally,a continuous-flow wastewater treatment system,using an MCS/IS membrane,demonstrates outstanding stability in TCH photodegradation.Utilizing response surface methodology and Fukui function analysis,the effects of various parameters on photocatalytic degradation rates,along with the associated pathways and intermediate products,have been thoroughly investigated.Toxicity assessments confirm the environmental safety of the treated effluents.Mechanistic studies show that the S-scheme heterojunction in the MCS/IS photocatalyst improves electron-hole separation,thereby enhancing photocatalytic performance.It is expected that this study will serve as a model for advancing the removal of emerging contaminants,further enhancing photocatalytic AOPs as sustainable water purification technologies.
基金supported by the Foundation Strengthening Program of China(No.2019-JCJQ-ZD-142-00)the Natural Science Foundation of Hebei Province,China(No.E2021202017)the Foundation of Guangdong Academy of Sciences,China(No.2021GDASYL-20210102002)。
文摘Zn-Al eutectoid alloy(ZA22)has ultra-high damping property,but its mechanical properties are still relatively low.In order to simultaneously improve the tensile strength and plasticity,a novel Al matrix composite inoculant containing in-situ formed Al_(2)O_(3) and Al3Zr particles was designed and used to reinforce the ZA22 alloy.The microstructure of the ZA22 alloy was significantly refined.Fine Al_(2)O_(3) particles were uniformly distributed in theαphase and the lamellar eutectoid structure,whereas Al3Zr particles were distributed in theαphase and at theα/ηinterface.Property tests showed that the tensile mechanical properties of the reinforced ZA22 alloys were significantly improved.The maximum tensile strength and elongation reached 355 MPa and 7.62%,which were 1.50 and 1.89 times those of the original ZA22 alloy,respectively.The increase in mechanical properties is attributed to the multiple strengthening and toughening factors constructed in the refined microstructure.
基金supported by the National Natural Science Foundation of China(No.52471040)the Natural Science Foundation of Shandong Province(No.ZR2022ME005).
文摘An Al_(2)O_(3)/Al-Cu-Mn composite was fabricated using a combination of ball milling and liquid-solid reaction,with a nominal composition of Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3).The composite contains reinforcement particles,including nano-sizedθ’and T(Al_(20)Cu_(2)Mn_(3))particles after T6 heat treatment,as well as in-situ synthesized nano-sizedγ-Al_(2)O_(3)particles.Tensile tests of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite and the Al-4Cu-0.5Mn base alloy after T6 treatment were carried out at room temperature and elevated temperatures(200°C,300°C,and 400°C).Compared with the base alloy,the yield strength of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite after T6 treatment increases significantly from 187 MPa to 263 MPa at room temperature.Simultaneously,at elevated temperatures,the yield strength is also enhanced,with a yield strength of 52 MPa at 400°C for this composite.The in-situ fabricatedγ-Al_(2)O_(3)particles,mainly distributed along the grain boundaries,are supposed to play the main strengthening role,especially at high temperatures.This work acts as a reference for designing composites for high-temperature applications.
基金Supported by National Natural Science Foundation of China(Grant No.52275033)National Natural Science Youth Foundation of China(Grant No.52205033)Hebei Provincial Natural Science Foundation of China(Grant No.E2021203019)。
文摘Serial-parallel manipulators are of great interest to academic community in recent years,especially those composed of classical parallel mechanisms.There have been many studies around 2(3RPS)and 2(3SPR)S-PMs,but unfortunately their inverse kinematics have not yet been resolved.This paper discovers that the unknown kinematic parameters of middle platform are responsible for the unresolvable of inverse kinematics,meanwhile the unknown kinematic parameters of middle platform also have huge coupling relationships.Therefore,to break through this challenges,the huge coupling relationships are decoupled layer by layer,the kinematic parameters of middle platform are solved by combining Sylvester's elimination method,and the inverse displacements of 2(3RPS)and 2(3SPR)S-PMs are obtained subsequently.This paper not only solves the inverse kinematics of classical 2(3RPS)and 2(3SPR)S-PMs,but also reveals the essence of the inverse kinematics of general(3-DOF)+(3-DOF)6-DOF S-PMs and proposes a corresponding solution.
基金the financial support from the 261Project of MIIT and Natural Science Foundation of Jiangsu Province(No.BK20240179)。
文摘The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as a high-strength substrate to support fast-ion-conducting polymer-in-salt(PIS)solid-state electrolytes,aiming to suppress lithium dendrite growth and improve full-cell performance.The Al_(2)O_(3)coating layer not only refines the wettability of polyimide porous film to PIS,but also performs as a high modulus protective layer to suppress the growth of lithium dendrites.The resulting PI/AO@PIS exhibits a small thickness of only 35μm with an outstanding tensile strength of 11.3 MPa and Young's modulus of 537.6 MPa.In addition,the PI/AO@PIS delivers a high ionic conductivity of 0.1 m S/cm at 25°C.As a result,the PI/AO@PIS enables symmetric Li cells to achieve exceptional cyclability for over 1000 h at 0.1 m A/cm2without noticeable lithium dendrite formation.Moreover,the PI/AO@PIS-based LiFePO4||Li full cells demonstrate outstanding rate performance(125.7 m Ah/g at 5 C)and impressive cycling stability(96.1%capacity retention at 1 C after 200 cycles).This work highlights the efficacy of enhancing the mechanical properties of polymer matrices and extending cell performance through the incorporation of a dense inorganic interface layer.
基金supported in part by the National Natural Science Foundation of China(No.52102218)the National Key Research and Development Program of China(No.2020YFA0710303)+2 种基金the Fujian Science&Technology Innovation Laboratory for Op-toelectronic Information of China(No.2021ZZ127)the Minjiang Scholar Professorship(No.GXRC-21004)the Natural Science Foundation of Fujian Province of China(No.2021J01594)。
文摘Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)through the high-temperature solid-state spontaneous crystallization method.Different from the cubicα-Pb_(3)P_(2)S_(8),theβ-Pb_(3)P_(2)S_(8)crystallizes in the orthorhombic Pbcn space group.Notably,β-Pb_(3)P_(2)S_(8)shows a large band gap of 2.37 e V in lead-based chalcogenides,wide infrared transparent window(2.5-15μm),and excellent thermal stability.Importantly,the experimental birefringence shows the largest value of0.26@550 nm in chalcogenides,even larger than the commercialized oxide materials.The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb^(2+)and S^(2-)in the[Pb S_n]polyhedrons.Meanwhile,the parallelly arranged polyhedral layers could improve the structural anisotropic.Therefore,this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
基金supported by the Natural Science Foundation of Henan Province(No.232300420329)Key Scientific Research Project of Colleges and Universities in Henan Province(Nos.23B430012,22A430028,and 25B430022)+2 种基金Henan Provincial Science and Technology Research Project(No.242102231064)National Natural Science Foundation of China(No.52202064)Luoyang Major Science and Technology Innovation Project(No.2301009A).
文摘β-Sialon has emerged as a promising material for enhancing the service life of Al_(2)O_(3)-C refractories due to its excellent physicochemical properties.The impact of varying concentrations of nanometer Al/Si alloy on the in-situ synthesis of β-Sialon within Al_(2)O_(3)-C refractory materials,as well as its oxidation behavior,was investigated.The findings indicate that the presence of Al/Si alloy promotes the formation of AlN and SiC whiskers at 1300℃,which subsequently facilitate the production of plate-like β-Sialon at 1500℃.Density functional theory analysis reveals that the(020)crystal plane of β-Sialon exhibits the lowest adsorption energy for Al2O and AlO molecules under the influence of iron atoms,suggesting a solid-liquid-vapor growth mechanism for β-Sialon formation.The introduction of these ceramic phases significantly enhances the mechanical properties of Al_(2)O_(3)-C refractories.Specifically,the addition of 6 wt.%Al/Si alloy yielded specimens with the highest cold modulus of rupture and cold crushing strength at 1500℃,achieving values of 35.2 and 127.5 MPa,respectively--representing increases of 40.1%and 37.4%.Furthermore,during high-temperature oxidation,the formation of plate-like β-Sialon leads to the development of a dense protective layer on the surface.This impedes the diffusion pathways of oxygen and consequently enhances the oxidation resistance of the refractory.
基金supported by the National Natural Science Foundation of China(Nos.52372090 and 52073177)the National Natural Science Foundation of Guangdong,China(No.2023A1515010947)Shenzhen Basic Research Program(No.JCYJ20220531102207017).
文摘Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/BiFeO_(3)(AAS/BFO),for photocatalytic degradation of ciprofloxacin from water.Experimental results verified the enhancement of combining heterostructure piezoelectric polarization effect,which promotes efficient migration and separation of photogenerated carriers due to the localized surface plasmon resonance effect of Ag nanoparticles.Additionally,the introduction of Ag_(2)S constructs a new heterostructure,that enhances the electron transport rate and improves the separation efficiency on electron-hole pairs.Under ultrasonic stimulation and visible light irradiation,the degradation efficiencies of 15%-AAS/BFO towards ciprofloxacin,methyl orange and methylene blue are significantly enhanced compared to pure BFO fibers.The demonstrated AAS/BFO material based on the synergistic piezoelectric effect and plasmon heterostructure shows potential in efficient organic pollutants water treatment and transforming mechanical energy into chemical energy.
基金supported by the National Natural Science Foundation of China(Nos.22276060 and 21976059)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012636)China Scholarship Council Scholarship(No.201906155006)。
文摘The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.
基金supported by the National Natural Science Foundation of China(Nos.22173057,52130204,12074241,11929401,12311530675)Science and Technology Commission of Shanghai Municipality(Nos.21JC1402700,22XD1400900,20501130600,21JC1402600)High-Performance Computing Center,Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Metal-ceramic composites combine the excellent properties of metals and ceramics,which have high strength,stability,and corrosion re-sistance.Al_(2)O_(3)/FeCo composites have been proven to be useful in ap-plications such as catalysts,mi-crowave absorption materials,and enhanced permeability dielectric.The understanding of the mechani-cal properties and dynamics at the atomic scale of the Al_(2)O_(3)/FeCo in-terface can promote the design and exploitment of metal-ceramic composites.In this work,we have obtained Young’s modulus and diffusion coefficient of the Al_(2)O_(3)/FeCo interface using molecular dynamics simulation,elucidated the structural characteristics of the Al_(2)O_(3)/FeCo interface at the atomic scale,and investigated the impact of atomic magnetism and the exter-nal magnetic field on the interface.Simulated results show that Young’s modulus of the Al_(2)O_(3)/FeCo interface is significantly improved compared with pure Al_(2)O_(3)and FeCo alloy at room and high temperatures.When the atomic magnetism and the external magnetic field are applied,Young’s modulus of the Al_(2)O_(3)/FeCo interface further increases to 612 GPa at 300 K and 602 GPa at 500 K.Moreover,the average density,diffusion coefficient,and radial distri-bution function are found to be modified substantially.This study will shed light on the atom-istic investigations of the metal-ceramic composites.
基金financially supported by National Natural Science Foundation of China(21773291,52303130,62205231,61904118,22002102)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJA210005)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_1710)Postgraduate Research&Practice Innovation Program of Suzhou University of Science and Technology(CLKYCX23_06)。
文摘Exploiting high-performance electrolyte holds the key for realization practical application of rechargeable magnesium batteries(RMBs).Herein,a new non-nucleophilic mononuclear electrolyte was developed and its electrochemical active species was identified as[Mg(DME)_(3)][GaCl_(4)]_(2) through single-crystal X-ray diffraction analysis.The as-synthesized Mg(GaCl_(4))_(2)-IL-DME electrolyte could achieve a high ionic conductivity(9.85 m S cm^(-1)),good anodic stability(2.9 V vs.Mg/Mg^(2+)),and highly reversible Mg plating/stripping.The remarkable electrochemical performance should be attributed to the in-situ formation of Mg^(2+)-conducting Ga_(5)Mg_(2)alloy layer at the Mg/electrolyte interface during electrochemical cycling,which not only efficiently protects the Mg anode from passivation,but also allows for rapid Mg-ion transport.Significantly,the Mg(GaCl_(4))_(2)-IL-DME electrolyte showed excellent compatibility with both conversion and intercalation cathodes.The Mg/S batteries with Mg(Ga Cl_(4))_(2)-IL-DME electrolyte and KB/S cathode showed a high specific capacity of 839 m Ah g^(-1)after 50 cycles at 0.1 C with the Coulombic efficiency of~100%.Moreover,the assembled Mg|Mo_6 S_8 batteries delivered a reversible discharge capacity of 85 m Ah g^(-1)after 120 cycles at 0.2 C.This work provides a universal electrolyte for the realization of high-performance and practical RMBs,especially Mg/S batteries.
