Poly(3-hexylthiophene)(P3HT)is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost.However,the intrinsic lo...Poly(3-hexylthiophene)(P3HT)is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost.However,the intrinsic low carrier density of P3 HT and poor contact between the P3HT/perovskite interface always lead to a low performance of the solar cell,while conventional chemical doping always makes the films unstable and limits the scalability.In this work,for the first time,we simultaneously enhanced the hole transporting properties of P3HT film and the interface of perovskite by doping it with a judiciously designed oxidized small molecule organic semiconductor.The organic salt not only can promote the lamellar crystallinity of P3HT to obtain better charge transport properties,but also reduce the defects of perovskite.As a result,we achieved champion efficiencies of 23.0%for small-area solar cells and 18.8%for larger-area modules(48.0 cm^(2)).This efficiency is the highest value for P3HT-based perovskite modules.Moreover,the solar cells show excellent operational stability,retaining over 95%of their initial efficiencies after1200 h of continuous operation.展开更多
Owing to the environmental and inherent advantages,nitrogen reduction reaction(NRR)by electrocatalysts attracts global attention.The surface engineering is widely employed to enhance the electrocatalytic activity by a...Owing to the environmental and inherent advantages,nitrogen reduction reaction(NRR)by electrocatalysts attracts global attention.The surface engineering is widely employed to enhance the electrocatalytic activity by atomic defects and heterostructure effects.A three-dimensional(3D)free-standing integrated electrode was fabricated by numerous nearly-single-crystal TiO_(2-δ)N_δnanowire arrays.Based on the high electronic conductivity network,it exposes numerous active sites as well to facilitate the selective nitrogen adsorption and*H adsorption suppression.The synergistic effects between Ti^(3+)and oxygen vacancy(O_v)boost the intrinsic catalytic activity,in which Ti^(3+)acquired electrons via Ovcan effectively activate the N≡N bond and make it easy to bind with protons.The energy barrier of primary protonation process(*N_(2)+H^(+)+e^(-)→*NNH)can be dramatically decreased.The highest ammonia yield rate(14.33μg h^(-1)mgcat^(-1))emerges at-0.2 V,while the optimal ammonia Faradaic efficiency(9.17%)is acquired at-0.1 V.Density functional theory(DFT)calculation reveals that the Ti^(3+)can be served as the active sites for nitrogen adsorption and activation,while ammonia synthesis is accomplished by the distal pathway.The high electronic conductivity integrated network and synergistic effects can significantly facilitate nitrogen absorption and accelerate electrocatalytic reaction kinetic,which are responsible for the excellent NRR performance at room temperature.展开更多
Sustainable metal-air batteries demand high-efficiency,environmentally-friendly,and non-precious metal-based electrocatalysts with bifunctionality for both the oxygen reduction reaction(ORR)and oxygen evolution reacti...Sustainable metal-air batteries demand high-efficiency,environmentally-friendly,and non-precious metal-based electrocatalysts with bifunctionality for both the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).In this research,novel functional carbon nanotubes with multi-active sites including well-dispersed single-atom iron throughout the walls and encapsulated ultrafine iron nanoparticles were synthesized as an electrocatalyst(FeNP@Fe-N-C)through one-step pyrolysis of metal-organic frameworks.High-resolution synchrotron powder X-ray diffraction and X-ray absorption spectroscopy were applied to characterize the unique structure of the electrocatalyst.In comparison to the commercial Pt/C and Ru O_(2)electrodes,the newly prepared FeNP@Fe-N-C presented a superb bifunctional performance with its narrow potential difference(Egap)of 0.73 V,which is ascribed to the metallic Fe nanoparticles that boosts the adsorption and activation of oxygen on the active sites with an enhanced O_(2)adsorption capacity of 7.88 cm^(3)g^(-1)and synergistically functionalizes the iron atoms dispersed on the nanotubes.A rechargeable zinc-air battery based on FeNP@Fe-N-C exhibited a superior open-circuit voltage(1.45 V),power density(106.5 m W cm^(-2)),and stable cycling performance.The green technique developed in this work for the fabrication of functional nanotubes raises the prospect of making more efficient electrocatalysts for sustainable energy cells.展开更多
Photocatalysis is considered as one of the most promising technologies to generate renewable energy and degrade environmental pollutants.Tremendous efforts have been made to improve photocatalytic efficiency.Among the...Photocatalysis is considered as one of the most promising technologies to generate renewable energy and degrade environmental pollutants.Tremendous efforts have been made to improve photocatalytic efficiency.Among these,tuning spin polarization and introducing an external magnetic field are considered two promising strategies to boost photocatalytic performance.Herein this review highlights the recent breakthroughs through manipulating spin states and applying external magnetic fields for enhancing photocatalytic reactions.The relevant characterization techniques and fundamental mechanisms are summarized.Spin polarization states of photocatalysts have received considerable attention due to their unique roles,including inhibiting the recombination of photoexcited carriers owing to spin orientation constraint,enhancing the reaction product selectivity,and reducing the reaction barriers via optimizing the absorption energy and binding strength.As for the effects of external magnetic field on photocatalytic performance,we mainly discuss the separation enhancement of photoinduced carriers under static and time-varying magnetic fields and the magneto-hydrodynamic effect of charged particles.Lastly,the negative magnetoresistance effect is discussed due to the synergistic effects of the electron spin state and an external magnetic field.These discussions in this review may provide new insights into designing new semiconductors for boosting photocatalytic performance in internal and external magnetic fields.展开更多
Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and with...Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and without extrusion process.The influences of microstructure evolution,introduced by DC casting and thermal-mechanical processing,on the hydrogen storage performance of Mg-Ni-Gd-Y-ZnCu alloys were comprehensively explored,using analytical electron microscopy and in-situ synchrotron powder X-ray diffraction.The result shows that the extruded alloy yields higher hydrogen absorption capacity and faster hydrogen ab/desorption kinetics.As subjected to extrusion processing,theα-Mg grains in the microstructure were significantly refined and a large number of 14H type long-period stacking ordered(LPSO)phases appeared on theα-Mg matrix.After activation,there were more nanosized Gd hydride/Mg2Ni intermetallics and finer chips.These modifications synergistically enhance the hydrogen storage properties.The findings have implications for the alloy design and manufacturing of magnesiumbased hydrogen storage materials with the advantages of rapid mass production and anti-oxidation.展开更多
Nitrogen-doped carbon catalysts with hierarchical porous structure are promising oxygen evolution reaction(OER)catalysts due to the faster mass transfer and better charge carrying ability.Herein,an exquisite high nitr...Nitrogen-doped carbon catalysts with hierarchical porous structure are promising oxygen evolution reaction(OER)catalysts due to the faster mass transfer and better charge carrying ability.Herein,an exquisite high nitrogen-containing ligand was designed and readily synthesized from the low-cost biomolecule adenine.Accordingly,three new MOFs(TJU-103,TJU-104 and TJU-105)were prepared using the Co(II)or Mn(II)ions as metal nodes.Through rationally controlling pyrolysis condition,in virtue of the high nitrogen content in well-defined periodic structure of the pristine MOFs,TJU-104–900 among the derived MOFs with hierarchical porous structure,i.e.,N-doped graphitic carbon encapsulating homogeneously distributed cobalt nanoparticles,could be conveniently obtained.Thanks to the synergistic effect of the hierarchical structure and well dispersed active components(i.e.,C=O,Co–Nx,graphitic C and N,pyridinic N),it could exhibit an overpotential of 280 mV@10mA/cm^(2)on carbon cloth for OER activity.This work provides the inspiration for fabrication of nitrogen-doped carbon/metal electrocatalysts from cost-effective and abundant biomolecules,which is promising for practical OER application.展开更多
It is widely accepted that further development of Pb-free solder alloys for improved processing and in-service properties of next-generation electronics,can be accelerated through a fundamental understanding of phase ...It is widely accepted that further development of Pb-free solder alloys for improved processing and in-service properties of next-generation electronics,can be accelerated through a fundamental understanding of phase transformation and microstructure control in Pb-free solder joints.Advanced characterization techniques including synchrotron radiation provide a comprehensive toolset to measure the composition,crystallography,morphology,and properties of the major components of solder alloys.The research using such techniques is reviewed in detail including the characterization of the eff ects of microalloy additions on the microstructure and properties of Pb-free solder joints,especially those on the intermetallic phases.The discoveries outlined are of scientific and industrial relevance and have implications for new solder alloy composition design and the reliability of lead-free solder joints.展开更多
17-4 precipitation hardening(PH)stainless steel is a multi-purpose engineering alloy offering an excellent trade-off between strength,toughness,and corrosion properties.It is commonly employed in additive manufacturin...17-4 precipitation hardening(PH)stainless steel is a multi-purpose engineering alloy offering an excellent trade-off between strength,toughness,and corrosion properties.It is commonly employed in additive manufacturing via laser powder bed fusion owing to its good weldability.However,there are remaining gaps in the processing-structure-property relationships for AM 17-4 PH that need to be addressed.For instance,discrepancies in literature regarding the as-built microstructure,subsequent development of the matrix phase upon heat treatment,as well as the as-built residual stress should be addressed to enable reproducible printing of 17-4 builds with superior properties.As such,this work applies a comprehensive characterisation and testing approach to 17-4 PH builds fabricated with different processing parameters,both in the as-built state and after standard heat treatments.Tensile properties in as-built samples both along and normal to the build direction were benchmarked against standard wrought samples in the solution annealed and quenched condition(CA).When testing along the build direction,higher ductility was observed for samples produced with a higher laser power(energy density)due to the promotion of interlayer cohesion and,hence,reduction of interlayer defects.Following the CA heat treatment,the austenite volume fraction increased to∼35%,resulting in a lower yield stress and greater work hardening capacity than the as-built specimens due to the transformation induced plasticity effect.Neutron diffraction revealed a slight reduction in the magnitude of residual stress with laser power.A concentric scanning strategy led to a higher magnitude of residual stress than a bidirectional raster pattern.展开更多
An effective regulation of the magnetism and interface of ferromagnetic materials is not only of great scientific significance,but also has an urgent need in modern industry.In this work,by using the first-principles ...An effective regulation of the magnetism and interface of ferromagnetic materials is not only of great scientific significance,but also has an urgent need in modern industry.In this work,by using the first-principles calculations,we demonstrate an effective approach to achieve non-volatile electrical control of ferromagnets,which proves this idea in multiferroic heterostructures of ferromagnetic La TiO_(3)and ferroelectric Bi FeO_(3).The results show that the magnetic properties and two-dimensional electron gas concentrations of La TiO_(3)films can be controlled by changing the polarization directions of Bi FeO_(3).The destroyed symmetry being introduced by ferroelectric polarization of the system leads to the transfer and reconstruction of the Ti-3 d electrons,which is the fundamental reason for the changing of magnetic properties.This multiferroic heterostructures will pave the way for non-volatile electrical control of ferromagnets and have potential applications.展开更多
The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are u...The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.展开更多
In this work,the influence of the hot-extrusion method on the hydrogen storage kinetics of Mg-Ni-Y alloy was investigated.It was shown that the extruded Mg_(91.47)Ni_(6.97)Y_(1.56)alloy exhibits improved hydriding and...In this work,the influence of the hot-extrusion method on the hydrogen storage kinetics of Mg-Ni-Y alloy was investigated.It was shown that the extruded Mg_(91.47)Ni_(6.97)Y_(1.56)alloy exhibits improved hydriding and dehydriding(H/D)kinetics,with a capacity of 3.5 wt.%H_(2)absorption within 60 s and 5.4 wt.%H_(2)des-orption within 5 min at 573 K.The dehydrogenation activation energy of extruded alloy is 71.4 kJ mol−1,smaller than that of as-cast alloy(140.5 kJ mol^(−1)).The enhancement of H/D kinetics is attributed to the microstructural refinement and increased grain/phase boundaries introduced by hot extrusion,as well as the catalytic effects from the in-situ generated and grain-refined Mg2 Ni and YH2 particles during the H/D process.Furthermore,the dehydrogenated rate-determining step transforms from hydrogen diffusion in the hydride(as-cast alloy)to the surface penetration of hydrogen atoms(extruded alloy).These findings provide crucial insights for the design of Mg-based hydrogen storage alloys in the future.展开更多
The GH3535 alloy samples were irradiated using 15-MeV Te^(4+) ions at 650℃to a dose of 0.5,3.0,10,and 20 dpa,respectively.The Te atoms distribution and microstructure evolution were examined by electron probe microan...The GH3535 alloy samples were irradiated using 15-MeV Te^(4+) ions at 650℃to a dose of 0.5,3.0,10,and 20 dpa,respectively.The Te atoms distribution and microstructure evolution were examined by electron probe microanalysis(EPMA)and transmission electron microscopy(TEM).The nano-indenter was then used to measure the nano-hardness changes of samples before and after irradiation.TEM results showed the formation of dislocation loops in the irradiated samples.Their mean diameters increase with the increase of irradiation dose and tends to be saturated when irradiation dose exceeds 10 dpa.The ratio of yield strength increments calculated by dispersed barrier hardening(DBH)model is basically consistent with that of nano-hardness increments measured by nano-indenter.In addition,the relationship between the nano-hardness increments and dpa for the GH3535 alloy irradiated by Te ions has been revealed in the study.展开更多
The magnetic structure of CsCo_2 Se_2 was investigated using single-crystal neutron diffraction technique. An antiferromagnetic transition with the propagation vector（0,0,1） was observed at TN= 78 K. The Co magnetic...The magnetic structure of CsCo_2 Se_2 was investigated using single-crystal neutron diffraction technique. An antiferromagnetic transition with the propagation vector（0,0,1） was observed at TN= 78 K. The Co magnetic moment 0.772（6） μB at 10 K pointing in the basal plane couples ferromagnetically in the plane, which stacks antiferromagnetically along the c direction. Tuning and suppressing the interplane antiferromagnetic interaction may be crucial to induce a superconducting state in the material.展开更多
The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4....The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4.96 K. The moment of 2.16#B per Co at 1.6K in the screw chain running along the c axis Mternates in the c axis. The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetieally Monk the other in-plane axis. This magnetic configuration breaks the four-fold symmetry of the tetragonM crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis. The very similar magnetic state to the isostructural BaCo2 V~ 08 warrants SrCo2 V2 08 as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.展开更多
Rechargeable sodium–oxygen(Na-O_(2))and sodium–carbon dioxide(Na-CO_(2))batteries have attracted intensive research attention in recent years owing to their advantages of high theoretical energy density,modest cost,...Rechargeable sodium–oxygen(Na-O_(2))and sodium–carbon dioxide(Na-CO_(2))batteries have attracted intensive research attention in recent years owing to their advantages of high theoretical energy density,modest cost,abundance of sodium resources,and promising potential for achieving real sodium–air batteries in large-scale energy storage systems.Nevertheless,current research on Na-O_(2)and Na-CO_(2)batteries is facing enormous challenges,such as low energy efficiency and limited cycle life,which are restricting their progress at the initial stage.Therefore,understanding their working principles,and the chemical and electrochemical reactions of the electrodes is indispensable to achieve their practical application and even the goal of true sodium–air batteries.This review aims to provide an overview of the research developments and future perspectives on Na-O_(2)and Na-CO_(2)batteries,which include the major aspects,such as working mechanisms,air cathode materials design strategies,sodium anode protection,and electrolyte stability.Moreover,the remaining issues and future research directions are also thoroughly discussed and presented.展开更多
As the primary suppliers of cyclable sodium ions,O3-type layer-structured manganese-based oxides are recognized as highly competitive cathode candidates for sodium-ion batteries.To advance the development of high-ener...As the primary suppliers of cyclable sodium ions,O3-type layer-structured manganese-based oxides are recognized as highly competitive cathode candidates for sodium-ion batteries.To advance the development of high-energy sodium-ion batteries,it is crucial to explore cathode materials operating at high voltages while maintaining a stable cycling behavior.The orbital and electronic structure of the octahedral center metal element plays a crucial role in maintaining the octahedra structural integrity and improving Na^(+)ion diffusion by introducing heterogeneous chemical bonding.Inspired by the abundant configuration of extra nuclear electrons and large ion radius,we employed trace amounts of tungsten in this study.The obtained cathode material can promote the reversibility of oxygen redox reactions in the high-voltage region and inhibit the loss of lattice oxygen.Additionally,the formation of a Na_(2)WO_(4) coating on the material surface can improve the interfacial stability and interface ions diffusion.It demonstrates an initial Coulombic efficiency(ICE)of 94.6%along with 168.5 mA h g^(-1 )discharge capacity within the voltage range of 1.9-4.35 V.These findings contribute to the advancement of high-energy sodium-ion batteries by providing insights into the benefits of tungsten doping and Na_(2)WO_(4) coating on cathode materials.展开更多
WC based cermet coatings have been considered as alternative replacements to the more traditional hard chrome plating for improved surface properties of aircraft landing gear. While these coatings are used in engineer...WC based cermet coatings have been considered as alternative replacements to the more traditional hard chrome plating for improved surface properties of aircraft landing gear. While these coatings are used in engineering applications requiring superior hardness and improved wear resistance, little is known about the corrosion resistance. In this study, three WC based composite coatings were deposited onto ferritic stainless steel substrates using high velocity oxy fuel (HVOF) technology. Salt spray testing and potentiodynamic scanning studies in a saline environment were conducted on the coatings. Characterisation of the coating structure, composition and morphology, was carried out, prior to and after corrosion testing, using optical microscopy, scanning electron microscopy and EDX elemental analysis. The results showed that poor corrosion performance was exhibited by all three coatings. This was attributed to the high levels of porosity and the presence of micro-cracks within the coatings, resulting in attack of the substrate directly by the saline environment and possible galvanic coupling effects between the substrate and the coating. Dissolution and / or erosion of specific phases within the coating, resulting in the formation of micro-channels and increased number / size of voids may have accelerated corrosion of the system.展开更多
基金financially supported by the National Natural Science Foundation of China(52472248 and 22075221)the Key Research and Development Project of Shanxi Province(202202060301003 and 202202060301015)the Innovation Program of Wuhan-Shuguang Project(2023010201020367)。
文摘Poly(3-hexylthiophene)(P3HT)is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost.However,the intrinsic low carrier density of P3 HT and poor contact between the P3HT/perovskite interface always lead to a low performance of the solar cell,while conventional chemical doping always makes the films unstable and limits the scalability.In this work,for the first time,we simultaneously enhanced the hole transporting properties of P3HT film and the interface of perovskite by doping it with a judiciously designed oxidized small molecule organic semiconductor.The organic salt not only can promote the lamellar crystallinity of P3HT to obtain better charge transport properties,but also reduce the defects of perovskite.As a result,we achieved champion efficiencies of 23.0%for small-area solar cells and 18.8%for larger-area modules(48.0 cm^(2)).This efficiency is the highest value for P3HT-based perovskite modules.Moreover,the solar cells show excellent operational stability,retaining over 95%of their initial efficiencies after1200 h of continuous operation.
基金financially supported by the Liao Ning Revitalization Talents Program(XLYC2007155)the Fundamental Research Funds for the Central Universities(N2025018,N2025009)。
文摘Owing to the environmental and inherent advantages,nitrogen reduction reaction(NRR)by electrocatalysts attracts global attention.The surface engineering is widely employed to enhance the electrocatalytic activity by atomic defects and heterostructure effects.A three-dimensional(3D)free-standing integrated electrode was fabricated by numerous nearly-single-crystal TiO_(2-δ)N_δnanowire arrays.Based on the high electronic conductivity network,it exposes numerous active sites as well to facilitate the selective nitrogen adsorption and*H adsorption suppression.The synergistic effects between Ti^(3+)and oxygen vacancy(O_v)boost the intrinsic catalytic activity,in which Ti^(3+)acquired electrons via Ovcan effectively activate the N≡N bond and make it easy to bind with protons.The energy barrier of primary protonation process(*N_(2)+H^(+)+e^(-)→*NNH)can be dramatically decreased.The highest ammonia yield rate(14.33μg h^(-1)mgcat^(-1))emerges at-0.2 V,while the optimal ammonia Faradaic efficiency(9.17%)is acquired at-0.1 V.Density functional theory(DFT)calculation reveals that the Ti^(3+)can be served as the active sites for nitrogen adsorption and activation,while ammonia synthesis is accomplished by the distal pathway.The high electronic conductivity integrated network and synergistic effects can significantly facilitate nitrogen absorption and accelerate electrocatalytic reaction kinetic,which are responsible for the excellent NRR performance at room temperature.
基金financially supported by grants 17210219 and T21-711/16R from the Research Grants Council of the Hong Kong governmentproject 51978369 from the National Natural Science Foundation of China。
文摘Sustainable metal-air batteries demand high-efficiency,environmentally-friendly,and non-precious metal-based electrocatalysts with bifunctionality for both the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).In this research,novel functional carbon nanotubes with multi-active sites including well-dispersed single-atom iron throughout the walls and encapsulated ultrafine iron nanoparticles were synthesized as an electrocatalyst(FeNP@Fe-N-C)through one-step pyrolysis of metal-organic frameworks.High-resolution synchrotron powder X-ray diffraction and X-ray absorption spectroscopy were applied to characterize the unique structure of the electrocatalyst.In comparison to the commercial Pt/C and Ru O_(2)electrodes,the newly prepared FeNP@Fe-N-C presented a superb bifunctional performance with its narrow potential difference(Egap)of 0.73 V,which is ascribed to the metallic Fe nanoparticles that boosts the adsorption and activation of oxygen on the active sites with an enhanced O_(2)adsorption capacity of 7.88 cm^(3)g^(-1)and synergistically functionalizes the iron atoms dispersed on the nanotubes.A rechargeable zinc-air battery based on FeNP@Fe-N-C exhibited a superior open-circuit voltage(1.45 V),power density(106.5 m W cm^(-2)),and stable cycling performance.The green technique developed in this work for the fabrication of functional nanotubes raises the prospect of making more efficient electrocatalysts for sustainable energy cells.
基金the National Natural Science Foundation of China(Nos.61774055,51871138,and U2102212)the Science and Technology Committee of Shanghai(No.19010500400)。
文摘Photocatalysis is considered as one of the most promising technologies to generate renewable energy and degrade environmental pollutants.Tremendous efforts have been made to improve photocatalytic efficiency.Among these,tuning spin polarization and introducing an external magnetic field are considered two promising strategies to boost photocatalytic performance.Herein this review highlights the recent breakthroughs through manipulating spin states and applying external magnetic fields for enhancing photocatalytic reactions.The relevant characterization techniques and fundamental mechanisms are summarized.Spin polarization states of photocatalysts have received considerable attention due to their unique roles,including inhibiting the recombination of photoexcited carriers owing to spin orientation constraint,enhancing the reaction product selectivity,and reducing the reaction barriers via optimizing the absorption energy and binding strength.As for the effects of external magnetic field on photocatalytic performance,we mainly discuss the separation enhancement of photoinduced carriers under static and time-varying magnetic fields and the magneto-hydrodynamic effect of charged particles.Lastly,the negative magnetoresistance effect is discussed due to the synergistic effects of the electron spin state and an external magnetic field.These discussions in this review may provide new insights into designing new semiconductors for boosting photocatalytic performance in internal and external magnetic fields.
基金synchrotron PXRD experiment was conducted at the Powder Diffraction beamline,ANSTO Australian Synchrotron under proposal Nos.AS211/PD/16842 and AS221/PD/17948G.Z.acknowledges the funding from the National Natural Science Foundation of China(No.51904352)Scientific Research Foundation of Hunan Provincial Education Department,China(No.22A0004)。
文摘Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and without extrusion process.The influences of microstructure evolution,introduced by DC casting and thermal-mechanical processing,on the hydrogen storage performance of Mg-Ni-Gd-Y-ZnCu alloys were comprehensively explored,using analytical electron microscopy and in-situ synchrotron powder X-ray diffraction.The result shows that the extruded alloy yields higher hydrogen absorption capacity and faster hydrogen ab/desorption kinetics.As subjected to extrusion processing,theα-Mg grains in the microstructure were significantly refined and a large number of 14H type long-period stacking ordered(LPSO)phases appeared on theα-Mg matrix.After activation,there were more nanosized Gd hydride/Mg2Ni intermetallics and finer chips.These modifications synergistically enhance the hydrogen storage properties.The findings have implications for the alloy design and manufacturing of magnesiumbased hydrogen storage materials with the advantages of rapid mass production and anti-oxidation.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21875165,22272118)the Fundamental Research Funds for the Central Universities(No.22120210529)+1 种基金the Science and Technology Commission of Shanghai Municipality,China(Nos.22ZR1464100,19DZ2271500)the Recruitment Program of Global Experts of China,and Research Grants from the City University of Hong Kong(Nos.CityU 11308420,6000716,9667217).
文摘Nitrogen-doped carbon catalysts with hierarchical porous structure are promising oxygen evolution reaction(OER)catalysts due to the faster mass transfer and better charge carrying ability.Herein,an exquisite high nitrogen-containing ligand was designed and readily synthesized from the low-cost biomolecule adenine.Accordingly,three new MOFs(TJU-103,TJU-104 and TJU-105)were prepared using the Co(II)or Mn(II)ions as metal nodes.Through rationally controlling pyrolysis condition,in virtue of the high nitrogen content in well-defined periodic structure of the pristine MOFs,TJU-104–900 among the derived MOFs with hierarchical porous structure,i.e.,N-doped graphitic carbon encapsulating homogeneously distributed cobalt nanoparticles,could be conveniently obtained.Thanks to the synergistic effect of the hierarchical structure and well dispersed active components(i.e.,C=O,Co–Nx,graphitic C and N,pyridinic N),it could exhibit an overpotential of 280 mV@10mA/cm^(2)on carbon cloth for OER activity.This work provides the inspiration for fabrication of nitrogen-doped carbon/metal electrocatalysts from cost-effective and abundant biomolecules,which is promising for practical OER application.
基金the funding from the National Natural Science Foundation of China(No.51904352)the Natural Science Foundation of Hunan Province(No.2020JJ5758)+3 种基金the State Key Laboratory of Solidification Processing in NPU(Grant No.SKLSP201904)funding from the University of Queensland-Nihon Superior Collaborative Research Programme(Grant No.2016001895)the Australian Research Council(ARC)Discovery(DP200101949)and Linkage(LP180100595)grantsthe financial support from JSPS KAKENHI(Grant No.JP17H06155)。
文摘It is widely accepted that further development of Pb-free solder alloys for improved processing and in-service properties of next-generation electronics,can be accelerated through a fundamental understanding of phase transformation and microstructure control in Pb-free solder joints.Advanced characterization techniques including synchrotron radiation provide a comprehensive toolset to measure the composition,crystallography,morphology,and properties of the major components of solder alloys.The research using such techniques is reviewed in detail including the characterization of the eff ects of microalloy additions on the microstructure and properties of Pb-free solder joints,especially those on the intermetallic phases.The discoveries outlined are of scientific and industrial relevance and have implications for new solder alloy composition design and the reliability of lead-free solder joints.
基金Funding by the AUSMURI program,Department of Industry,In-novation and Science,Australia is acknowledged.
文摘17-4 precipitation hardening(PH)stainless steel is a multi-purpose engineering alloy offering an excellent trade-off between strength,toughness,and corrosion properties.It is commonly employed in additive manufacturing via laser powder bed fusion owing to its good weldability.However,there are remaining gaps in the processing-structure-property relationships for AM 17-4 PH that need to be addressed.For instance,discrepancies in literature regarding the as-built microstructure,subsequent development of the matrix phase upon heat treatment,as well as the as-built residual stress should be addressed to enable reproducible printing of 17-4 builds with superior properties.As such,this work applies a comprehensive characterisation and testing approach to 17-4 PH builds fabricated with different processing parameters,both in the as-built state and after standard heat treatments.Tensile properties in as-built samples both along and normal to the build direction were benchmarked against standard wrought samples in the solution annealed and quenched condition(CA).When testing along the build direction,higher ductility was observed for samples produced with a higher laser power(energy density)due to the promotion of interlayer cohesion and,hence,reduction of interlayer defects.Following the CA heat treatment,the austenite volume fraction increased to∼35%,resulting in a lower yield stress and greater work hardening capacity than the as-built specimens due to the transformation induced plasticity effect.Neutron diffraction revealed a slight reduction in the magnitude of residual stress with laser power.A concentric scanning strategy led to a higher magnitude of residual stress than a bidirectional raster pattern.
基金the National Natural Science Foundation of China(Grant No.12047517)the International Cooperation Project of Science and Technology of Henan Province,China(Grant No.182102410096)+1 种基金the Natural Science Foundation of Henan Province,China(Grant No.202300410069)the China Postdoctoral Science Foundation(Grant Nos.2020M682274 and 2020TQ0089)。
文摘An effective regulation of the magnetism and interface of ferromagnetic materials is not only of great scientific significance,but also has an urgent need in modern industry.In this work,by using the first-principles calculations,we demonstrate an effective approach to achieve non-volatile electrical control of ferromagnets,which proves this idea in multiferroic heterostructures of ferromagnetic La TiO_(3)and ferroelectric Bi FeO_(3).The results show that the magnetic properties and two-dimensional electron gas concentrations of La TiO_(3)films can be controlled by changing the polarization directions of Bi FeO_(3).The destroyed symmetry being introduced by ferroelectric polarization of the system leads to the transfer and reconstruction of the Ti-3 d electrons,which is the fundamental reason for the changing of magnetic properties.This multiferroic heterostructures will pave the way for non-volatile electrical control of ferromagnets and have potential applications.
基金Y.C.and J.C.are contributed equally to the paper.Project supported by the National Natural Science Foundation of China (U19A2017)the Fundamental Research Funds for the Central South University and the Australian Research Council (DP180100731 and DP180100568)。
文摘The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.
基金supported by the National Key Re-search and Development Program of China(No.2023YFB3809103)the National Natural Science Foundation of China(No.U23A20128)the Fundamental Research Funds for the Central Universities(Project No.2023CDJXY-016).
文摘In this work,the influence of the hot-extrusion method on the hydrogen storage kinetics of Mg-Ni-Y alloy was investigated.It was shown that the extruded Mg_(91.47)Ni_(6.97)Y_(1.56)alloy exhibits improved hydriding and dehydriding(H/D)kinetics,with a capacity of 3.5 wt.%H_(2)absorption within 60 s and 5.4 wt.%H_(2)des-orption within 5 min at 573 K.The dehydrogenation activation energy of extruded alloy is 71.4 kJ mol−1,smaller than that of as-cast alloy(140.5 kJ mol^(−1)).The enhancement of H/D kinetics is attributed to the microstructural refinement and increased grain/phase boundaries introduced by hot extrusion,as well as the catalytic effects from the in-situ generated and grain-refined Mg2 Ni and YH2 particles during the H/D process.Furthermore,the dehydrogenated rate-determining step transforms from hydrogen diffusion in the hydride(as-cast alloy)to the surface penetration of hydrogen atoms(extruded alloy).These findings provide crucial insights for the design of Mg-based hydrogen storage alloys in the future.
基金the National Natural Science Foundation of China(Grant Nos.11975304 and 12022515).
文摘The GH3535 alloy samples were irradiated using 15-MeV Te^(4+) ions at 650℃to a dose of 0.5,3.0,10,and 20 dpa,respectively.The Te atoms distribution and microstructure evolution were examined by electron probe microanalysis(EPMA)and transmission electron microscopy(TEM).The nano-indenter was then used to measure the nano-hardness changes of samples before and after irradiation.TEM results showed the formation of dislocation loops in the irradiated samples.Their mean diameters increase with the increase of irradiation dose and tends to be saturated when irradiation dose exceeds 10 dpa.The ratio of yield strength increments calculated by dispersed barrier hardening(DBH)model is basically consistent with that of nano-hardness increments measured by nano-indenter.In addition,the relationship between the nano-hardness increments and dpa for the GH3535 alloy irradiated by Te ions has been revealed in the study.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB921700)the National Natural Science Foundation of China(Grant No.11190024)+2 种基金the Fundamental Research Funds for the Central Universities,Chinathe Research Funds of Renmin University of China(Grant Nos.17XNLF04 and 17XNLF06)support from China Scholarship Council
文摘The magnetic structure of CsCo_2 Se_2 was investigated using single-crystal neutron diffraction technique. An antiferromagnetic transition with the propagation vector（0,0,1） was observed at TN= 78 K. The Co magnetic moment 0.772（6） μB at 10 K pointing in the basal plane couples ferromagnetically in the plane, which stacks antiferromagnetically along the c direction. Tuning and suppressing the interplane antiferromagnetic interaction may be crucial to induce a superconducting state in the material.
基金Supported by the National Basic Research Program of China under Grant Nos 2012CB921700 and 2011CBA00112the National Natural Science Foundation of China under Grant Nos 11034012 and 11190024
文摘The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4.96 K. The moment of 2.16#B per Co at 1.6K in the screw chain running along the c axis Mternates in the c axis. The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetieally Monk the other in-plane axis. This magnetic configuration breaks the four-fold symmetry of the tetragonM crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis. The very similar magnetic state to the isostructural BaCo2 V~ 08 warrants SrCo2 V2 08 as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.
基金financially supported by an Australian Research Council(ARC)Discovery Project(DP180101453)
文摘Rechargeable sodium–oxygen(Na-O_(2))and sodium–carbon dioxide(Na-CO_(2))batteries have attracted intensive research attention in recent years owing to their advantages of high theoretical energy density,modest cost,abundance of sodium resources,and promising potential for achieving real sodium–air batteries in large-scale energy storage systems.Nevertheless,current research on Na-O_(2)and Na-CO_(2)batteries is facing enormous challenges,such as low energy efficiency and limited cycle life,which are restricting their progress at the initial stage.Therefore,understanding their working principles,and the chemical and electrochemical reactions of the electrodes is indispensable to achieve their practical application and even the goal of true sodium–air batteries.This review aims to provide an overview of the research developments and future perspectives on Na-O_(2)and Na-CO_(2)batteries,which include the major aspects,such as working mechanisms,air cathode materials design strategies,sodium anode protection,and electrolyte stability.Moreover,the remaining issues and future research directions are also thoroughly discussed and presented.
基金supported by the National Natural Science Foundation of China(Grant No.52272194)LiaoNing Revitalization Talents Program(Grant No.XLYC2007155)。
文摘As the primary suppliers of cyclable sodium ions,O3-type layer-structured manganese-based oxides are recognized as highly competitive cathode candidates for sodium-ion batteries.To advance the development of high-energy sodium-ion batteries,it is crucial to explore cathode materials operating at high voltages while maintaining a stable cycling behavior.The orbital and electronic structure of the octahedral center metal element plays a crucial role in maintaining the octahedra structural integrity and improving Na^(+)ion diffusion by introducing heterogeneous chemical bonding.Inspired by the abundant configuration of extra nuclear electrons and large ion radius,we employed trace amounts of tungsten in this study.The obtained cathode material can promote the reversibility of oxygen redox reactions in the high-voltage region and inhibit the loss of lattice oxygen.Additionally,the formation of a Na_(2)WO_(4) coating on the material surface can improve the interfacial stability and interface ions diffusion.It demonstrates an initial Coulombic efficiency(ICE)of 94.6%along with 168.5 mA h g^(-1 )discharge capacity within the voltage range of 1.9-4.35 V.These findings contribute to the advancement of high-energy sodium-ion batteries by providing insights into the benefits of tungsten doping and Na_(2)WO_(4) coating on cathode materials.
文摘WC based cermet coatings have been considered as alternative replacements to the more traditional hard chrome plating for improved surface properties of aircraft landing gear. While these coatings are used in engineering applications requiring superior hardness and improved wear resistance, little is known about the corrosion resistance. In this study, three WC based composite coatings were deposited onto ferritic stainless steel substrates using high velocity oxy fuel (HVOF) technology. Salt spray testing and potentiodynamic scanning studies in a saline environment were conducted on the coatings. Characterisation of the coating structure, composition and morphology, was carried out, prior to and after corrosion testing, using optical microscopy, scanning electron microscopy and EDX elemental analysis. The results showed that poor corrosion performance was exhibited by all three coatings. This was attributed to the high levels of porosity and the presence of micro-cracks within the coatings, resulting in attack of the substrate directly by the saline environment and possible galvanic coupling effects between the substrate and the coating. Dissolution and / or erosion of specific phases within the coating, resulting in the formation of micro-channels and increased number / size of voids may have accelerated corrosion of the system.
