Ba0.85Ca0.15Ti0.9Zr0.1O3 （BCTZ） lead-free piezoelectric ceramics co-doped with CeO2 （x=0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%） and Li2CO3 （0.6 wt.%） were prepared by conventional solid-state reaction m...Ba0.85Ca0.15Ti0.9Zr0.1O3 （BCTZ） lead-free piezoelectric ceramics co-doped with CeO2 （x=0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%） and Li2CO3 （0.6 wt.%） were prepared by conventional solid-state reaction method. Influence of CeO2 doping amount on the piezoelectric properties, dielectric properties, phase composition and microstructure of prepared BCTZ lead-free piezoelectric ceramics doped with Li2CO3 were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM） and other analytical methods. The results showed that the sintered temperature of BCTZ lead-free piezoelectric ceramics doped with CeO2 decreased greatly when Li2CO3 doping amount was 0.6 wt.%;a pure perovskite structure of BCTZ lead-free piezoelectric ceramics co-doped with Li2CO3 and CeO2 and sintered at 1050 ℃ could also be obtained. The piezoelectric constant （d33）, the relative permit-tivity （εr） and the planar electromechanical coupling factor （kp） of BCTZ ceramics doped with Li2CO3 increased firstly and then de-creased, the dielectric loss （tanδ） decreased firstly and then increased and decreased at last when CeO2 doping amount increased. The influence of CeO2 doping on the properties of BCTZ lead-free piezoelectric ceramics doped with Li2CO3 were caused by“soft effect”and “hard effect”piezoelectric additive and causing lattice distortion. When CeO2 doping amount （x） was 0.2 wt.%, the BCTZ ceramics doped with Li2CO3 （0.6 wt.%） and sintered at 1050 ℃ possessed the best piezoelectric property and dielectric property with d33 of 436 pC/N, kp of 48.3%,εr of 3650, tanδof 1.5%.展开更多
In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperat...In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperature(T_(c))of 1D superconductors is low.In this work,we theoretically investigate the possible high T_(c) superconductivity of(5,5)carbon nanotube(CNT).The pristine(5,5)CNT is a Dirac semimetal and can be modulated into a semiconductor by full hydrogenation.Interestingly,by further hole doping,it can be regulated into a metallic state with the sp3-hybridized𝜎electrons metalized,and a giant Kohn anomaly appears in the optical phonons.The two factors together enhance the electron–phonon coupling,and lead to high-T_(c) superconductivity.When the hole doping concentration of hydrogenated-(5,5)CNT is 2.5 hole/cell,the calculated T_(c) is 82.3 K,exceeding the boiling point of liquid nitrogen.Therefore,the predicted hole-doped hydrogenated-(5,5)CNT provides a new platform for 1D high-T_(c) superconductivity and may have potential applications in 1D nanodevices.展开更多
This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0...This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.展开更多
The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising c...The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.展开更多
Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer e...Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer efficiency of current catalysts,the further application of AOPs technology is limited.Here,it is proposed that the interfacial electric field can be controlled by bor(B)-doped FeNC catalysts,which shows significant advantages in the efficient generation,release and participation of reactive oxygen species(ROS)in the reaction.The super exchange interaction between Fe sites and N and B sites is realized through the directional transfer of electrons in the interfacial electric field,which ensures the high efficiency and stability of the PMS catalytic process.B doping increases the d orbitals distribution at Fermi level,which facilitates enhanced electron transition activity,thereby promoting the effective generation of (1)^O_(2).At the same time,orbital hybridization causes the center of the d band to move to a lower energy level,which not only contributes to the desorption process of (1)^O_(2),but also accelerates its release.In addition,B-doping also improved the adsorption capacity of organic pollutants and shortened the migration distance of ROS,thereby significantly improving the degradation efficiency of ECs.The B-doping strategy outlined offers a novel approach to the development of FeNC catalysts,it lays a theoretical foundation and offers technical insights for the integration of PMS/AOPs technology in the ECs management.展开更多
The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long ...The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long cycle life.Herein,a trace amount of Mg-B co-doping in LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2(NMC622)is investigated in this work,which shows improved structural and electrochemical stability of 1%Mg-0.5%B co-doped material at both 30 and 55℃in coin-cell.Comprehensive chemical composition,structural,and surface analysis are carried out in this paper.It was found that all the selected materials have a similar composition to the target.Moreover,Mg and B doping have different effects on the crystal structural change of NMC622,to be more specific,the c-lattice parameter increases with Mg doping,while the Li^(+)/Ni^(2+)mixing content increases when B was incorporated into the lattice.Furthermore,the microstructure of primary particles was changed by B doping significantly as confirmed by the SEM images.There were marginal benefits in terms of structural and electrochemical stability of materials introduced by Mg or B sole doping.In comparison,incorporating a suitable amount of both Mg and B into NMC622,we found the capacity retention of cells was noticeably improved by reducing the impedance growth and preventing cation mixing during cycling.This study demonstrates the importance of co-incorporation of Mg,B,and optimizing the co-dopant content to stabilize NMC622 as cathode for lithium-ion batteries.展开更多
Alpha nickel hydroxide has better performances than commercial beta nickel hydroxide. However, the main defect is that α-phase is difficult to synthesize and easily transformed to β-phase Ni（OH）2 upon aging in a s...Alpha nickel hydroxide has better performances than commercial beta nickel hydroxide. However, the main defect is that α-phase is difficult to synthesize and easily transformed to β-phase Ni（OH）2 upon aging in a strong alkaline solution. In this study, the Al-Co, Al-Yb, Yb-Co and Al-Yb-Co multiple doping was used respectively. By controlling the amount of sodium carbonate, the α-Ni（OH）2 was prepared by ultrasonic-assisted precipitation. And the influence of sodium carbonate on the crystalline phase and structure stability for alpha nickel hydroxide was studied. The results demonstrate that, with increasing amount, the biphase nickel hydroxide transforms to pure alpha nickel hydroxide gradually, and the structure stability is also improved. When the amount of sodium carbonate is 2 g, the sample still keeps α-Ni（OH）2 after being aged for 30 days, for Al-Yb-Co-Ni（OH）2. And when the amount is less than 2 g, the phase transformations exist in the samples with different extents. These results demonstrated that the amount of sodium carbonate is a critical factor to maintain the structural stability of α-Ni（OH）2.展开更多
All-solid-state Li batteries(ASSLBs)using solid electrolytes(SEs)have gained significant attention in recent years considering the safety issue and their high energy density.Despite these advantages,the commercializat...All-solid-state Li batteries(ASSLBs)using solid electrolytes(SEs)have gained significant attention in recent years considering the safety issue and their high energy density.Despite these advantages,the commercialization of ASSLBs still faces challenges regarding the electrolyte/electrodes interfaces and growth of Li dendrites.Elemental doping is an effective and direct method to enhance the performance of SEs.Here,we report an Al-F co-doping strategy to improve the overall properties including ion conductivity,high voltage stability,and cathode and anode compatibility.Particularly,the Al-F co-doping enables the formation of a thin Li-Al alloy layer and fluoride interphases,thereby constructing a relatively stable interface and promoting uniform Li deposition.The similar merits of Al-F co-doping are also revealed in the Li-argyrodite series.ASSLBs assembled with these optimized electrolytes gain good electrochemical performance,demonstrating the universality of Al-F co-doping towards advanced SEs.展开更多
Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corros...Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine.In contrast to the oxygen evolution reaction (OER)and chlorin ion oxidation reaction (ClOR),glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative.Herein,a Ru doping cobalt phosphide (Ru-CoP_(2)) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR,for the concurrent productions of hydrogen and value-added formate.The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP_(2)to Ru-CoOOH,accounting for the superior GOR performance.Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP_(2)as both anode and cathode,requiring only a low voltage of 1.43 V at 100 mA cm^(-2),which was 250 m V lower than that in alkaline seawater.This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.展开更多
In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-dept...In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry.Typically,the isotropy of a specific facet provides a perfect support for studying heteroatom doping.Herein,this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals.The presence of iron not only modifies the electronic structure of lithium tantalate,improving its light absorption capacity,but also functions as an active site for the nitrogen adsorption and activation.The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95μg cm^(−2)h^(−1),which is three times higher than that of undoped lithium tantalate.The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating.This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.展开更多
Magnetostrictive Fe-Ga alloys have captivated substantial focus in biomedical applications because of their exceptional transition efficiency and favorable cytocompatibility.Nevertheless,Fe-Ga alloys always exhibit fr...Magnetostrictive Fe-Ga alloys have captivated substantial focus in biomedical applications because of their exceptional transition efficiency and favorable cytocompatibility.Nevertheless,Fe-Ga alloys always exhibit frustrating magnetostriction coefficients when presented in bulk dimensions.It is well-established that the magnetostrictive performance of Fe-Ga alloys is intimately linked to their phase and crystal structures.In this study,various concentrations of boron(B)were doped into Fe_(81)Ga_(19) alloys via the laser-beam powder bed fusion(LPBF)technique to tailor the crystal and phase structures,thereby improving the magnetostrictive performance.The results revealed the capacity for quick solidification of the LPBF process in expediting the solid solution of B element,which increased both lattice distortion and dislocations within the Fe-Ga matrix.These factors contributed to an elevation in the density of the modified-D0_(3) phase structure.Moreover,the prepared Fe-Ga-B alloys also exhibited a(001)preferred grain orientation caused by the high thermal gradients during the LPBF process.As a result,a maximum magnetostriction coefficient of 105 ppm was achieved in the(Fe_(81)Ga_(19))_(98.5)B_(1.5) alloy.In alternating magnetic fields,all the LPBF-prepared alloys showed good dynamic magnetostriction response without visible hysteresis,while the(Fe_(81)Ga_(19))_(98.5)B_(1.5) alloy presented a notable enhancement of~30%in magnetostriction coefficient when compared with the Fe_(81)Ga_(19) alloy.Moreover.the(Fe_(81)Ga_(19))_(98.5)B_(1.5) alloy exhibited favorable biocompatibility and osteogenesis,as confirmed by increased alkaline phosphatase(ALP)activity and the formation of mineralized nodules.These findings suggest that the B-doped Fe-Ga alloys combined with the LPBF technique hold promise for the development of bulk magnetostrictive alloys that are applicable for bone repair applications.展开更多
The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity...The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity fading and phase change of MnO_(2)-based materials in aqueous zinc ion batteries(AZIBs).Here,this study doped high valent vanadium ions into MnO_(2)(VMO-x)to inhibit manganese's Jahn-Teller effect.Through a series of characterizations,such as X-ray diffraction(XRD),Raman spectroscopy,and scanning electron microscopy(SEM),it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO_(2),facilitating the transport of ions into the interlayer.Additionally,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)demonstrated vanadium doped could effectively adjust the electronic structure,decreasing the average oxidation state of manganese,thereby inhibiting the Jahn-Teller effect and significantly enhancing the stability of the VMO-x cathode.The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn^(2+),optimized its electron transport capacity,and led to better electrical conductivity and reaction kinetics of the VMO-5.Benefiting from this,the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79%after 2000 cycles,demonstrating excellent electrochemical performance.Furthermore,the mechanism of H^(+)/Zn^(2+)co-intercalation/deintercalation was demonstrated through mechanism analysis.Finally,the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices.This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.展开更多
Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effect...Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.展开更多
Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-depositi...Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_(1-x)Mn_(x)O_(3),prolonging the lifespan in acidic conditions by 14 times.The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH^(-).The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO_(2),which ensures that the long-term stability of LaCo_(1-x)Mn_(x)O_(3)is 70 h instead of 5 h for LaCoO_(3).Mn doping enhances the deprotonation of^(*)OOH→O_(2)in acidic environments.Notably,the over-potential of optimized LaCo_(1-x)Mn_(x)O_(3)is 345 mV at 10 mA cm^(-2)for acidic OER.This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.展开更多
The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied...The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.展开更多
Wide-bandgap two-dimensional (2D) β-TeO_(2) has been reported as a high-mobility p-type transparent semiconductor [Nat. Electron. 4 277 (2021)], attracting significant attention. This "breakthrough" not onl...Wide-bandgap two-dimensional (2D) β-TeO_(2) has been reported as a high-mobility p-type transparent semiconductor [Nat. Electron. 4 277 (2021)], attracting significant attention. This "breakthrough" not only challenges the conventional characterization of TeO_(2) as an insulator but also conflicts with the anticipated difficulty in hole doping of TeO_(2) by established chemical trends. Notably, the reported Fermi level of 0.9 eV above the valence band maximum actually suggests that the material is an insulator, contradicting the high hole density obtained by Hall effect measurement. Furthermore, the detected residual Se and the possible reduced elemental Te in the 2D β-TeO_(2) samples introduces complexity, considering that elemental Se, Te, and Te_(1−x)Se_(x) themselves are high-mobility p-type semiconductors. Therefore, doubts regarding the true cause of the p-type conductivity observed in the 2D β-TeO_(2) samples arise. In this Letter, we employ density functional theory calculations to illustrate that TeO_(2), whether in its bulk forms of α-, β-, or γ-TeO_(2), or in the 2D β-TeO_(2) nanosheets, inherently exhibits insulating properties and poses challenges in carrier doping due to its shallow conduction band minimum and deep valence band maximum. Our findings shed light on the insulating properties and doping difficulty of TeO_(2), contrasting with the claimed p-type conductivity in the 2D β-TeO_(2) samples, prompting inquiries into the true origin of the p-type conductivity.展开更多
As a 3D printing method,laser powder bed fusion(LPBF)technology has been extensively proven to offer significant advantages in fabricating complex structured specimens,achieving ultra-fine microstructures,and enhancin...As a 3D printing method,laser powder bed fusion(LPBF)technology has been extensively proven to offer significant advantages in fabricating complex structured specimens,achieving ultra-fine microstructures,and enhancing performances.In the domain of manufacturing melt-grown oxide ceramics,it encounters substantial challenges in suppressing crack defects during the rapid solidification process.The strategic integration of high entropy alloys(HEA),leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the obstacles.The ingenious doping of HEA parti-cles preserves the eutectic microstructures of the Al_(2)O_(3)/GdAlO_(3)(GAP)/ZrO_(2)ceramic composite.The high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF,effectively reducing crack initiation and growth.Due to in-creased curvature forces and intense Marangoni convection at the top of the molt pool,particle collision intensifies,leading to the tendency of HEA particles to agglomerate at the upper part of the molt pool.However,this phenomenon can be effectively alleviated in the remelting process of subsequent layer de-position.Furthermore,a portion of the HEA particles partially dissolves and sinks into the molten pool,acting as heterogeneous nucleation particles,inducing the formation of equiaxed eutectic and leading pri-mary phase nucleation.Some HEA particles diffuse into the lamellar ternary eutectic structures,further promoting the refinement of eutectic microstructures due to increased undercooling.The innovative dop-ing of HEA particles has effectively facilitated the fabrication of turbine-structured,conical,and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm,demonstrating significant developmental potential in the field of ceramic composite manufacturing.展开更多
By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts d...By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts developed thus far still suffer from the issues of much lower activity and metal leaching,which severely hinder their practical application.Here,we demonstrate that incorporating phosphorus(P)atoms into graphitic carbon nitride(PCN)supports facilitates charge transfer from Rh to the PCN support,thus largely enhancing electronic metal-support interactions(EMSIs).In the styrene hydroformylation reaction,the activity of Rh_(1)/PCN single-atom catalysts(SACs)with varying P contents exhibited a volcano-shaped relationship with P doping,where the Rh_(1)/PCN SAC with optimal P doping showed exceptional activity,approximately 5.8-and 3.3-fold greater than that of the Rh_(1)/g-C_(3)N_(4)SAC without P doping and the industrial homogeneous catalyst HRh(CO)(PPh_(3))_(3),respectively.In addition,the optimal Rh_(1)/PCN SAC catalyst also demonstrated largely enhanced multicycle stability without any visible metal aggregation owing to the increased EMSIs,which sharply differed from the severe metal aggregation of large nanoparticles on the Rh_(1)/g-C_(3)N_(4)SAC.Mechan-istic studies revealed that the enhanced catalytic performance could be attributed to electron-deficient Rh species,which reduced CO adsorption while simultaneously promoting alkene adsorption through increased EMSIs.These findings suggest that tuning EMSIs is an effective way to achieve SACs with high activity and durability.展开更多
The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this wor...The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this work,we strategi-cally engineer the active site structure of Co-N-C via B substitution,which is accomplished by the pyrolysis of ammonium borate.During this process,the in-situ generated NH_(3)gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure.The well-designed CoB_(1)N_(3)active site endows Co with higher charge density and stronger adsorption energy toward oxygen species,potentially accelerating ORR kinetics.As expected,the resulting Co-B/N-C catalyst exhibited superior ORR performance over Co-N-C counterpart,with 40 mV,and fivefold en-hancement in half-wave potential and turnover frequency(TOF).More importantly,the excellent ORR performance could be translated into membrane electrode assembly(MEA)in a fuel cell test,delivering an impressive peak power density of 824 mW·cm^(-2),which is currently the best among Co-based catalysts under the same conditions.This work not only demon-strates an effective method for designing advanced catalysts,but also affords a highly promising non-precious metal ORR electrocatalyst for fuel cell applications.展开更多
Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent lumine...Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent luminescent material applications.At present,YAGG:Ce^(3+),Cr^(3+)powders exhibit good persistent performance,but their persistent performance of ceramics still needs to be further improved to meet the new requirements.In this work,(Y_(0.998)Ce_(0.002))_(3)(Al_(1-x)Cr_(x))_(2)Ga_(3)O_(12) ceramics with different Cr^(3+)doping concentrations were prepared by solid-state reaction,including air pre-sintering,hot isostatic pressing(HIP)post-treatment and air annealing,to investigate the effects of Cr^(3+)doping concentration on the microstructure,optical properties and persistent performance of the ceramics.The results showed that as the doping concentration of Cr^(3+)increased from 0.025%to 0.2%(in atom),no significant effect of Cr^(3+)concentration on the morphology of pre-sintered ceramics or HIP post-treatment ceramics was observed,but the in-line transmittance gradually increased while the persistent performance gradually decreased.Among them,YAGG:Ce^(3+),Cr^(3+)ceramics doped with 0.025%Cr^(3+)showed the strongest initial luminescence intensity exceeding 6055 mcd/m^(2) and a persistent time of 1030 min after air pre-sintering combined with HIP post-treatment and air annealing.By optimizing the Cr^(3+)doping concentration and the fabrication process,the persistent luminescence(PersL)performance of the YAGG:Ce^(3+),Cr^(3+)ceramics was obviously improved.展开更多
基金supported by Project of Combination of Producing,Learning and Studying of Guangdong Province and Education Department(2011B090400027)
文摘Ba0.85Ca0.15Ti0.9Zr0.1O3 （BCTZ） lead-free piezoelectric ceramics co-doped with CeO2 （x=0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%） and Li2CO3 （0.6 wt.%） were prepared by conventional solid-state reaction method. Influence of CeO2 doping amount on the piezoelectric properties, dielectric properties, phase composition and microstructure of prepared BCTZ lead-free piezoelectric ceramics doped with Li2CO3 were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM） and other analytical methods. The results showed that the sintered temperature of BCTZ lead-free piezoelectric ceramics doped with CeO2 decreased greatly when Li2CO3 doping amount was 0.6 wt.%;a pure perovskite structure of BCTZ lead-free piezoelectric ceramics co-doped with Li2CO3 and CeO2 and sintered at 1050 ℃ could also be obtained. The piezoelectric constant （d33）, the relative permit-tivity （εr） and the planar electromechanical coupling factor （kp） of BCTZ ceramics doped with Li2CO3 increased firstly and then de-creased, the dielectric loss （tanδ） decreased firstly and then increased and decreased at last when CeO2 doping amount increased. The influence of CeO2 doping on the properties of BCTZ lead-free piezoelectric ceramics doped with Li2CO3 were caused by“soft effect”and “hard effect”piezoelectric additive and causing lattice distortion. When CeO2 doping amount （x） was 0.2 wt.%, the BCTZ ceramics doped with Li2CO3 （0.6 wt.%） and sintered at 1050 ℃ possessed the best piezoelectric property and dielectric property with d33 of 436 pC/N, kp of 48.3%,εr of 3650, tanδof 1.5%.
基金supported by the National Natural Science Foundation of China (Grant Nos.12074213 and 11574108)the Major Basic Program of Natural Science Foundation of Shandong Province (Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Province (Grant No.ZR2023MA082)。
文摘In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperature(T_(c))of 1D superconductors is low.In this work,we theoretically investigate the possible high T_(c) superconductivity of(5,5)carbon nanotube(CNT).The pristine(5,5)CNT is a Dirac semimetal and can be modulated into a semiconductor by full hydrogenation.Interestingly,by further hole doping,it can be regulated into a metallic state with the sp3-hybridized𝜎electrons metalized,and a giant Kohn anomaly appears in the optical phonons.The two factors together enhance the electron–phonon coupling,and lead to high-T_(c) superconductivity.When the hole doping concentration of hydrogenated-(5,5)CNT is 2.5 hole/cell,the calculated T_(c) is 82.3 K,exceeding the boiling point of liquid nitrogen.Therefore,the predicted hole-doped hydrogenated-(5,5)CNT provides a new platform for 1D high-T_(c) superconductivity and may have potential applications in 1D nanodevices.
基金financially supported by the National Natural Science Foundation of China(No.22309067)the Open Project Program of the State Key Laboratory of Materials-Oriented Chemical Engineering,China(No.KL21-05)the Marine Equipment and Technology Institute,Jiangsu University of Science and Technology,China(No.XTCX202404)。
文摘This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.
基金financial support from 2024 Domestic Visiting Scholar Program for Teachers'Professional Development in Universities(Grant No.FX2024022)National Natural Science Foundation of China(Grant No.61904043)。
文摘The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.
基金supported by the National Natural Science Foundation of China(No.22278156)the Guangdong Special Support Program Project(No.2021JC060580)+1 种基金the Young Elite Scientists Sponsorship Program by CAST-Doctoral Student Special Plan,the China Scholarship Council Program(No.202406150148)the Natural Science Foundation of Guangdong Province(No.2023A1515011186).
文摘Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer efficiency of current catalysts,the further application of AOPs technology is limited.Here,it is proposed that the interfacial electric field can be controlled by bor(B)-doped FeNC catalysts,which shows significant advantages in the efficient generation,release and participation of reactive oxygen species(ROS)in the reaction.The super exchange interaction between Fe sites and N and B sites is realized through the directional transfer of electrons in the interfacial electric field,which ensures the high efficiency and stability of the PMS catalytic process.B doping increases the d orbitals distribution at Fermi level,which facilitates enhanced electron transition activity,thereby promoting the effective generation of (1)^O_(2).At the same time,orbital hybridization causes the center of the d band to move to a lower energy level,which not only contributes to the desorption process of (1)^O_(2),but also accelerates its release.In addition,B-doping also improved the adsorption capacity of organic pollutants and shortened the migration distance of ROS,thereby significantly improving the degradation efficiency of ECs.The B-doping strategy outlined offers a novel approach to the development of FeNC catalysts,it lays a theoretical foundation and offers technical insights for the integration of PMS/AOPs technology in the ECs management.
基金financially supported by the National Natural Science Foundation of China(Project numbers.51834004,51774076,51704062)the Fundamental Research Funds for the Central Universities(N2025019)。
文摘The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long cycle life.Herein,a trace amount of Mg-B co-doping in LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2(NMC622)is investigated in this work,which shows improved structural and electrochemical stability of 1%Mg-0.5%B co-doped material at both 30 and 55℃in coin-cell.Comprehensive chemical composition,structural,and surface analysis are carried out in this paper.It was found that all the selected materials have a similar composition to the target.Moreover,Mg and B doping have different effects on the crystal structural change of NMC622,to be more specific,the c-lattice parameter increases with Mg doping,while the Li^(+)/Ni^(2+)mixing content increases when B was incorporated into the lattice.Furthermore,the microstructure of primary particles was changed by B doping significantly as confirmed by the SEM images.There were marginal benefits in terms of structural and electrochemical stability of materials introduced by Mg or B sole doping.In comparison,incorporating a suitable amount of both Mg and B into NMC622,we found the capacity retention of cells was noticeably improved by reducing the impedance growth and preventing cation mixing during cycling.This study demonstrates the importance of co-incorporation of Mg,B,and optimizing the co-dopant content to stabilize NMC622 as cathode for lithium-ion batteries.
基金Funded by the National Natural Science Foundation of China(No.51604087)the Science and Technology Program of Guangdong Province of China(No.2016A010104019)the Science and Technology Program of Guangzhou City of China(No.201607010001)
文摘Alpha nickel hydroxide has better performances than commercial beta nickel hydroxide. However, the main defect is that α-phase is difficult to synthesize and easily transformed to β-phase Ni（OH）2 upon aging in a strong alkaline solution. In this study, the Al-Co, Al-Yb, Yb-Co and Al-Yb-Co multiple doping was used respectively. By controlling the amount of sodium carbonate, the α-Ni（OH）2 was prepared by ultrasonic-assisted precipitation. And the influence of sodium carbonate on the crystalline phase and structure stability for alpha nickel hydroxide was studied. The results demonstrate that, with increasing amount, the biphase nickel hydroxide transforms to pure alpha nickel hydroxide gradually, and the structure stability is also improved. When the amount of sodium carbonate is 2 g, the sample still keeps α-Ni（OH）2 after being aged for 30 days, for Al-Yb-Co-Ni（OH）2. And when the amount is less than 2 g, the phase transformations exist in the samples with different extents. These results demonstrated that the amount of sodium carbonate is a critical factor to maintain the structural stability of α-Ni（OH）2.
基金supported by the National Natural Science Foundation of China(Nos.52172243,52371215)。
文摘All-solid-state Li batteries(ASSLBs)using solid electrolytes(SEs)have gained significant attention in recent years considering the safety issue and their high energy density.Despite these advantages,the commercialization of ASSLBs still faces challenges regarding the electrolyte/electrodes interfaces and growth of Li dendrites.Elemental doping is an effective and direct method to enhance the performance of SEs.Here,we report an Al-F co-doping strategy to improve the overall properties including ion conductivity,high voltage stability,and cathode and anode compatibility.Particularly,the Al-F co-doping enables the formation of a thin Li-Al alloy layer and fluoride interphases,thereby constructing a relatively stable interface and promoting uniform Li deposition.The similar merits of Al-F co-doping are also revealed in the Li-argyrodite series.ASSLBs assembled with these optimized electrolytes gain good electrochemical performance,demonstrating the universality of Al-F co-doping towards advanced SEs.
基金National Natural Science Foundation of China (Nos. 42276035, 22309030)Guangdong Basic and Applied Basic Research Foundation (Nos. 2023A1515012589,2020A1515110473)Key Plat Form Programs and Technology Innovation Team Project of Guangdong Provincial Department of Education (Nos. 2019GCZX002, 2020KCXTD011)。
文摘Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine.In contrast to the oxygen evolution reaction (OER)and chlorin ion oxidation reaction (ClOR),glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative.Herein,a Ru doping cobalt phosphide (Ru-CoP_(2)) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR,for the concurrent productions of hydrogen and value-added formate.The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP_(2)to Ru-CoOOH,accounting for the superior GOR performance.Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP_(2)as both anode and cathode,requiring only a low voltage of 1.43 V at 100 mA cm^(-2),which was 250 m V lower than that in alkaline seawater.This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.
基金supported by Natural Science Foundation of Shandong Province(Nos.ZR2022YQ42,ZR2021JQ15,ZR2021QE011,ZR2021ZD20,2022GJJLJRC-01)Innovative Team Project of Jinan(No.2021GXRC019)the National Natural Science Foundation of China(Nos.52022037,52202366).
文摘In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry.Typically,the isotropy of a specific facet provides a perfect support for studying heteroatom doping.Herein,this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals.The presence of iron not only modifies the electronic structure of lithium tantalate,improving its light absorption capacity,but also functions as an active site for the nitrogen adsorption and activation.The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95μg cm^(−2)h^(−1),which is three times higher than that of undoped lithium tantalate.The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating.This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.
基金supported by the National Natural Science Foundation of China(Nos.52275395,51935014,and 82072084)the Science and Technology Innovation Program of Hunan Province(No.2023RC3046)+4 种基金the Young Elite Scientists Sponsorship Program byCAST(No.2020QNRC002)the NationalKeyResearchand Development Program of China(No.2023YFB4605800)the Central South University Innovation-Driven Research Programme(No.2023CXQD023)the Jiangxi Provincial Natural Science Foundation of China(No.20224ACB204013)the Project of State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Central South University.
文摘Magnetostrictive Fe-Ga alloys have captivated substantial focus in biomedical applications because of their exceptional transition efficiency and favorable cytocompatibility.Nevertheless,Fe-Ga alloys always exhibit frustrating magnetostriction coefficients when presented in bulk dimensions.It is well-established that the magnetostrictive performance of Fe-Ga alloys is intimately linked to their phase and crystal structures.In this study,various concentrations of boron(B)were doped into Fe_(81)Ga_(19) alloys via the laser-beam powder bed fusion(LPBF)technique to tailor the crystal and phase structures,thereby improving the magnetostrictive performance.The results revealed the capacity for quick solidification of the LPBF process in expediting the solid solution of B element,which increased both lattice distortion and dislocations within the Fe-Ga matrix.These factors contributed to an elevation in the density of the modified-D0_(3) phase structure.Moreover,the prepared Fe-Ga-B alloys also exhibited a(001)preferred grain orientation caused by the high thermal gradients during the LPBF process.As a result,a maximum magnetostriction coefficient of 105 ppm was achieved in the(Fe_(81)Ga_(19))_(98.5)B_(1.5) alloy.In alternating magnetic fields,all the LPBF-prepared alloys showed good dynamic magnetostriction response without visible hysteresis,while the(Fe_(81)Ga_(19))_(98.5)B_(1.5) alloy presented a notable enhancement of~30%in magnetostriction coefficient when compared with the Fe_(81)Ga_(19) alloy.Moreover.the(Fe_(81)Ga_(19))_(98.5)B_(1.5) alloy exhibited favorable biocompatibility and osteogenesis,as confirmed by increased alkaline phosphatase(ALP)activity and the formation of mineralized nodules.These findings suggest that the B-doped Fe-Ga alloys combined with the LPBF technique hold promise for the development of bulk magnetostrictive alloys that are applicable for bone repair applications.
基金supported the National Key Research and Development Program of China(No.2024YFA1409900)the National Natural Science Foundation of China(Nos.62101296 and 52303335)+2 种基金the China Postdoctoral Science Foundation(Nos.2021M702656 and 2023M730099)the Natural Science Foundation of Shaanxi Province(Nos.2021JQ-756 and 2021M702656)the Graduate Innovation Fund of the School of Mechanical Engineering,Shaanxi University of Technology(No.SLGJX202404)。
文摘The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity fading and phase change of MnO_(2)-based materials in aqueous zinc ion batteries(AZIBs).Here,this study doped high valent vanadium ions into MnO_(2)(VMO-x)to inhibit manganese's Jahn-Teller effect.Through a series of characterizations,such as X-ray diffraction(XRD),Raman spectroscopy,and scanning electron microscopy(SEM),it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO_(2),facilitating the transport of ions into the interlayer.Additionally,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)demonstrated vanadium doped could effectively adjust the electronic structure,decreasing the average oxidation state of manganese,thereby inhibiting the Jahn-Teller effect and significantly enhancing the stability of the VMO-x cathode.The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn^(2+),optimized its electron transport capacity,and led to better electrical conductivity and reaction kinetics of the VMO-5.Benefiting from this,the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79%after 2000 cycles,demonstrating excellent electrochemical performance.Furthermore,the mechanism of H^(+)/Zn^(2+)co-intercalation/deintercalation was demonstrated through mechanism analysis.Finally,the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices.This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.
基金National Key Research and Development Program of China (2022YFE0206300)National Natural Science Foundation of China (U21A2081,22075074, 22209047)+3 种基金Guangdong Basic and Applied Basic Research Foundation (2024A1515011620)Hunan Provincial Natural Science Foundation of China (2024JJ5068)Foundation of Yuelushan Center for Industrial Innovation (2023YCII0119)Student Innovation Training Program (S202410532594,S202410532357)。
文摘Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.
基金financially supported by the Shandong Provincial Natural Science Foundation(ZR2023LFG005)the National Natural Science Foundation of China(Nos.22479161,52274308 and U22B20144)the Fundamental Research Funds for the Central Universities(No.24CX03012A)。
文摘Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_(1-x)Mn_(x)O_(3),prolonging the lifespan in acidic conditions by 14 times.The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH^(-).The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO_(2),which ensures that the long-term stability of LaCo_(1-x)Mn_(x)O_(3)is 70 h instead of 5 h for LaCoO_(3).Mn doping enhances the deprotonation of^(*)OOH→O_(2)in acidic environments.Notably,the over-potential of optimized LaCo_(1-x)Mn_(x)O_(3)is 345 mV at 10 mA cm^(-2)for acidic OER.This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.
基金support from the National Key Research and Development Program of China(No.2022YFE0137400)the National Natural Science Foundation of China(Grant No.62274040).
文摘The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.
基金supported by the National Natural Science Foundation of China(Grant Nos.52372150,12088101,and 11991060)the National Key R&D Program of China(Grant No.2022YFB4200305)。
文摘Wide-bandgap two-dimensional (2D) β-TeO_(2) has been reported as a high-mobility p-type transparent semiconductor [Nat. Electron. 4 277 (2021)], attracting significant attention. This "breakthrough" not only challenges the conventional characterization of TeO_(2) as an insulator but also conflicts with the anticipated difficulty in hole doping of TeO_(2) by established chemical trends. Notably, the reported Fermi level of 0.9 eV above the valence band maximum actually suggests that the material is an insulator, contradicting the high hole density obtained by Hall effect measurement. Furthermore, the detected residual Se and the possible reduced elemental Te in the 2D β-TeO_(2) samples introduces complexity, considering that elemental Se, Te, and Te_(1−x)Se_(x) themselves are high-mobility p-type semiconductors. Therefore, doubts regarding the true cause of the p-type conductivity observed in the 2D β-TeO_(2) samples arise. In this Letter, we employ density functional theory calculations to illustrate that TeO_(2), whether in its bulk forms of α-, β-, or γ-TeO_(2), or in the 2D β-TeO_(2) nanosheets, inherently exhibits insulating properties and poses challenges in carrier doping due to its shallow conduction band minimum and deep valence band maximum. Our findings shed light on the insulating properties and doping difficulty of TeO_(2), contrasting with the claimed p-type conductivity in the 2D β-TeO_(2) samples, prompting inquiries into the true origin of the p-type conductivity.
基金supported by the National Natural Science Foundation of China(Nos.52130204,52174376,52202070,51822405)Guangdong Basic and Applied Basic Research Foundation(No.2021B1515120028)+6 种基金TQ Innovation Foundation(No.23-TQ09-02-ZT-01-005)Aeronautical Science Foundation of China(No.20220042053001)Science and Technology Innovation Team Plan of Shaanxi Province(No.2021TD-17)Key R&D Project of Shaanxi Province(No.2024GX-YBXM-220)Thousands Person Plan of Jiangxi Province(JXSQ2020102131)Fundamental Research Funds for the Central Universities(Nos.D5000230348,D5000220057)China Scholarship Council(Nos.202206290133,202306290190).
文摘As a 3D printing method,laser powder bed fusion(LPBF)technology has been extensively proven to offer significant advantages in fabricating complex structured specimens,achieving ultra-fine microstructures,and enhancing performances.In the domain of manufacturing melt-grown oxide ceramics,it encounters substantial challenges in suppressing crack defects during the rapid solidification process.The strategic integration of high entropy alloys(HEA),leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the obstacles.The ingenious doping of HEA parti-cles preserves the eutectic microstructures of the Al_(2)O_(3)/GdAlO_(3)(GAP)/ZrO_(2)ceramic composite.The high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF,effectively reducing crack initiation and growth.Due to in-creased curvature forces and intense Marangoni convection at the top of the molt pool,particle collision intensifies,leading to the tendency of HEA particles to agglomerate at the upper part of the molt pool.However,this phenomenon can be effectively alleviated in the remelting process of subsequent layer de-position.Furthermore,a portion of the HEA particles partially dissolves and sinks into the molten pool,acting as heterogeneous nucleation particles,inducing the formation of equiaxed eutectic and leading pri-mary phase nucleation.Some HEA particles diffuse into the lamellar ternary eutectic structures,further promoting the refinement of eutectic microstructures due to increased undercooling.The innovative dop-ing of HEA particles has effectively facilitated the fabrication of turbine-structured,conical,and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm,demonstrating significant developmental potential in the field of ceramic composite manufacturing.
基金supported by the Petrochemical Research Institute Foundation(21-CB-09-01)the National Natural Science Foundation of China(22302186,22025205)+1 种基金the China Postdoctoral Science Foundation(2022M713030,2023T160618)the Fundamental Research Funds for the Central Universities(WK2060000058,WK2060000038).
文摘By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts developed thus far still suffer from the issues of much lower activity and metal leaching,which severely hinder their practical application.Here,we demonstrate that incorporating phosphorus(P)atoms into graphitic carbon nitride(PCN)supports facilitates charge transfer from Rh to the PCN support,thus largely enhancing electronic metal-support interactions(EMSIs).In the styrene hydroformylation reaction,the activity of Rh_(1)/PCN single-atom catalysts(SACs)with varying P contents exhibited a volcano-shaped relationship with P doping,where the Rh_(1)/PCN SAC with optimal P doping showed exceptional activity,approximately 5.8-and 3.3-fold greater than that of the Rh_(1)/g-C_(3)N_(4)SAC without P doping and the industrial homogeneous catalyst HRh(CO)(PPh_(3))_(3),respectively.In addition,the optimal Rh_(1)/PCN SAC catalyst also demonstrated largely enhanced multicycle stability without any visible metal aggregation owing to the increased EMSIs,which sharply differed from the severe metal aggregation of large nanoparticles on the Rh_(1)/g-C_(3)N_(4)SAC.Mechan-istic studies revealed that the enhanced catalytic performance could be attributed to electron-deficient Rh species,which reduced CO adsorption while simultaneously promoting alkene adsorption through increased EMSIs.These findings suggest that tuning EMSIs is an effective way to achieve SACs with high activity and durability.
基金the National Key Research and Development Program of China(2022YFB4004100)National Natural Science Foundation of China(22272161,22179126)+1 种基金the Jilin Province Science and Technology Development Program(YDZJ202202CXJD011,20240101019JC)Jilin Province major science and technology project(222648GX0105103875)for financial supports.
文摘The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this work,we strategi-cally engineer the active site structure of Co-N-C via B substitution,which is accomplished by the pyrolysis of ammonium borate.During this process,the in-situ generated NH_(3)gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure.The well-designed CoB_(1)N_(3)active site endows Co with higher charge density and stronger adsorption energy toward oxygen species,potentially accelerating ORR kinetics.As expected,the resulting Co-B/N-C catalyst exhibited superior ORR performance over Co-N-C counterpart,with 40 mV,and fivefold en-hancement in half-wave potential and turnover frequency(TOF).More importantly,the excellent ORR performance could be translated into membrane electrode assembly(MEA)in a fuel cell test,delivering an impressive peak power density of 824 mW·cm^(-2),which is currently the best among Co-based catalysts under the same conditions.This work not only demon-strates an effective method for designing advanced catalysts,but also affords a highly promising non-precious metal ORR electrocatalyst for fuel cell applications.
基金National Key R&D Program of China(2023YFB3506600)。
文摘Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent luminescent material applications.At present,YAGG:Ce^(3+),Cr^(3+)powders exhibit good persistent performance,but their persistent performance of ceramics still needs to be further improved to meet the new requirements.In this work,(Y_(0.998)Ce_(0.002))_(3)(Al_(1-x)Cr_(x))_(2)Ga_(3)O_(12) ceramics with different Cr^(3+)doping concentrations were prepared by solid-state reaction,including air pre-sintering,hot isostatic pressing(HIP)post-treatment and air annealing,to investigate the effects of Cr^(3+)doping concentration on the microstructure,optical properties and persistent performance of the ceramics.The results showed that as the doping concentration of Cr^(3+)increased from 0.025%to 0.2%(in atom),no significant effect of Cr^(3+)concentration on the morphology of pre-sintered ceramics or HIP post-treatment ceramics was observed,but the in-line transmittance gradually increased while the persistent performance gradually decreased.Among them,YAGG:Ce^(3+),Cr^(3+)ceramics doped with 0.025%Cr^(3+)showed the strongest initial luminescence intensity exceeding 6055 mcd/m^(2) and a persistent time of 1030 min after air pre-sintering combined with HIP post-treatment and air annealing.By optimizing the Cr^(3+)doping concentration and the fabrication process,the persistent luminescence(PersL)performance of the YAGG:Ce^(3+),Cr^(3+)ceramics was obviously improved.
