The two-dimensional van der Waals layered semiconductor In_(2)Se_(3) has emerged as a promising candidate for non-volatile ferroelectric memory,optoelectronic devices,and polymorphic phase engineering.Polymorphic In_(...The two-dimensional van der Waals layered semiconductor In_(2)Se_(3) has emerged as a promising candidate for non-volatile ferroelectric memory,optoelectronic devices,and polymorphic phase engineering.Polymorphic In_(2)Se_(3) typically stabilizes in three distinct phases:α-,β′-,and β^(*)-In_(2)Se_(3),each dominant within specific temperature ranges.Although the crystal structures and ferroelectric properties of these phases have been widely studied,the unambiguous assignment of their in-plane and out-of-plane ferroelectric behaviors,as well as the mechanisms governing their phase transitions,remains a subject of active debate.In this study,we investigate the evolution of atomic and electronic structures in molecular beam epitaxy-grown ultrathin In_(2)Se_(3) films through correlated microstructural and macroscopic physical property analysis.By employing scanning tunneling microscopy/spectroscopy,temperature-dependent Raman spectroscopy,and piezoresponse force microscopy,we demonstrate a reversible temperature-induced phase transition between the in-plane ferroelectric β^(*)and antiferroelectric β′phases.Furthermore,we confirm robust out-of-plane ferroelectric polarization in the as-grown films and achieve an electric-field-driven transition from the β^(*)to β′phase.Our findings not only advance the fundamental understanding of phase transitions and polarization evolution in two-dimensional semiconductors but also open new avenues for the design of tunable,non-volatile ferroelectric memory devices.展开更多
Aqueous iron-ion batteries are regarded as one of the most promising candidates for grid applications owing to their low cost,high theoretical capacity,and excellent stability of iron in aqueous electrolytes.However,t...Aqueous iron-ion batteries are regarded as one of the most promising candidates for grid applications owing to their low cost,high theoretical capacity,and excellent stability of iron in aqueous electrolytes.However,the slow Fe(de)insertion caused by the high polarity of Fe^(2+)makes it difficult to match suitable cathode materials.Herein,defect-rich MoS_(2)with abundant 1T phase is synthesized and successfully applied in aqueous iron-ion batteries.Benefit from abundant active sites generated by the heteroatom incorporation and S vacancy,as well as the highly conductive 1T phase,it can deliver a specific capacity of 123 mAh/g at a current density of 100mA/g,and demonstrates an impressive capacity retention of 88%after 600 cycles at 200mA/g.This work presents a novel pathway for the advancement of cathode materials for aqueous iron-ion batteries.展开更多
Precisely reducing the size of metal-organic frameworks(MOFs)derivatives is an effective strategy to manipulate their phase engineering owing to size-dependent oxidation;however,the underlying relationship between the...Precisely reducing the size of metal-organic frameworks(MOFs)derivatives is an effective strategy to manipulate their phase engineering owing to size-dependent oxidation;however,the underlying relationship between the size of derivatives and phase engineering has not been clarified so far.Herein,a spatial confined growth strategy is proposed to encapsulate small-size MOFs derivatives into hollow carbon nanocages.It realizes that the hollow cavity shows a significant spatial confinement effect on the size of confined MOFs crystals and subsequently affects the dielectric polarization due to the phase hybridization with tunable coherent interfaces and heterojunctions owing to size-dependent oxidation motion,yielding to satisfied microwave attenuation with an optimal reflection loss of-50.6 d B and effective bandwidth of 6.6 GHz.Meanwhile,the effect of phase hybridization on dielectric polarization is deeply visualized,and the simulated calculation and electron holograms demonstrate that dielectric polarization is shown to be dominant dissipation mechanism in determining microwave absorption.This spatial confined growth strategy provides a versatile methodology for manipulating the size of MOFs derivatives and the understanding of size-dependent oxidation-induced phase hybridization offers a precise inspiration in optimizing dielectric polarization and microwave attenuation in theory.展开更多
Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of di...Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of different phases on the EMW absorbing performance,such as 1T and 2H phase,is still not studied.In this work,micro-1T/2H MoS_(2) is achieved via a facile one-step hydrother-mal route,in which the 1T phase is induced by the intercalation of vip molecules and ions.The EMW absorption mechanism of single MoS_(2) is revealed by presenting a comparative study between 1T/2H MoS_(2) and 2H MoS_(2).As a result,1T/2H MoS_(2) with the matrix loading of 15%exhibits excellent microwave absorption property than 2H MoS_(2).Furthermore,taking the advantage of 1T/2H MoS_(2),a flexible EMW absorbers that ultrathin 1T/2H MoS_(2)grown on the carbon fiber also performs outstanding performance only with the matrix loading of 5%.This work offers necessary reference to improve microwave absorption performance by phase engineering and design a new type of flexible electromagnetic wave absorption material to apply for the portable microwave absorption electronic devices.展开更多
Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase ...Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase to the 1T phase has been proven to be a significant method to improve the catalytic activity.However,precisely controllable phase engineering of MoSe_(2) has rarely been reported.Herein,by in situ Li ions intercalation in MoSe_(2),a precisely controllable phase evolution from 2H-MoSe_(2) to 1T-MoSe_(2) was realized.More importantly,the definite functional relationship between cut-off voltage and phase structure was first identified for phase engineering through in situ observation and modulation methods.The sulfur host(CNFs/1T-MoSe_(2))presents high charge density,strong polysulfides adsorption,and catalytic kinetics.Moreover,Li-S cells based on it display capacity retention of 875.3mAh g^(-1) after 500 cycles at 1 C and an areal capacity of 8.71mAh cm^(-2) even at a high sulfur loading of 8.47mg cm^(-2).Furthermore,the flexible pouch cell exhibiting decent performance will endow a promising potential in the wearable energy storage field.This study proposes an effective strategy to precisely control the phase structure of MoSe_(2),which may provide the reference to fabricate the highly efficient electrocatalysts for LSBs and other energy systems.展开更多
In this work,taking NiSe_(2)as a prototype to be used as cocatalyst in photocatalytic hydrogen evolution,we demonstrate that the crystal phase of NiSe_(2)plays a vital role in determining the catalytic stability,rathe...In this work,taking NiSe_(2)as a prototype to be used as cocatalyst in photocatalytic hydrogen evolution,we demonstrate that the crystal phase of NiSe_(2)plays a vital role in determining the catalytic stability,rather than activity.Theoretical and experimental results indicate that the phase structure shows negligible influence to the charge transport and hydrogen adsorption capacity.When integrating with carbon nitride(CN)photocatalyst forming hybrids(m-NiSe_(2)/CN and p-NiSe_(2)/CN),the hybrids show comparable photocatalytic hydrogen evolution rates(3.26μmol/h and 3.75μmol/h).Unlike the comparable catalytic activity,we found that phase-engineered NiSe_(2)exhibits distinct stability,i.e.,m-NiSe_(2)can evolve H_(2) steadily,but p-NiSe_(2)shows a significant decrease in catalytic process(∼57.1%decrease in 25 h).The factor leading to different catalytic stability can be ascribed to the different surface conversion behavior during photocatalytic process,i.e.,chemical structure of m-NiSe_(2)can be well preserved in catalytic process,but partial p-NiSe_(2)tends to be converted to NiOOH.展开更多
Hydrogen(H2)is considered to be a promising substitute for fossil fuels.Two-dimensional(2D)nanomaterials have exhibited an efficient electrocatalytic capacity to catalyze hydrogen evolution reaction(HER).Particularly,...Hydrogen(H2)is considered to be a promising substitute for fossil fuels.Two-dimensional(2D)nanomaterials have exhibited an efficient electrocatalytic capacity to catalyze hydrogen evolution reaction(HER).Particularly,phase engineering of 2D nanomaterials is opening a novel research direction to endow 2D nanostructures with fascinating properties for deep applications in catalyzing HER.In this review,we briefly summarize the research progress and present the current challenges on phase engineering of 2D nanomaterials for their applications in electrocatalytic HER.Our summary will be of significance to provide fundamental understanding for designing novel 2D nanomaterials with unconventional phases to electrochemically catalyze HER.展开更多
Nickel-manganese binary layered oxides with high working potential and low cost are potential candidates for sodium-ion batteries,but their electrochemical properties are highly related to compositional diversity.Dive...Nickel-manganese binary layered oxides with high working potential and low cost are potential candidates for sodium-ion batteries,but their electrochemical properties are highly related to compositional diversity.Diverse composite materials with various phase structures of P3,P2/P3,P2,P2/O3,and P2/P3/O3 were synthesized by manipulating the sodium content and calcination conditions,leading to the construction of a synthetic phase diagram for Na_(x)Ni_(0.25)Mn_(0.75)O_(2)(0.45≤x≤1.1).Then,we compared the electrochemical characteristics and structural evolution during the desodiation/sodiation process of P2,P2/P3,P2/03,and P2/P3/O3-Na_(x)Ni_(0.25)Mn_(0.75)O_(2).Among them,P2/P3-Na0.75Ni0.25Mn0.75O2exhibits the best rate capability of 90.9 mA h g^(-1)at 5 C,with an initial discharge capacity of 142.62 mA h g^(-1)at 0.1 C and a capacity retention rate of 78.25%after 100 cycles at 1 C in the voltage range of 2-4.3 V.The observed superior sodium storage performance of P2/P3 hybrids compared to other composite phases can be attributed to the enhanced Na^(+)transfer dynamic,reduction of the Jahn-teller effect,and improved reaction reversibility induced by the synergistic effect of P2 and P3 phases.The systematic research and exploration of phases in Na_(x)Ni_(0.25)Mn_(0.75)O_(2)provide new sights into high-performance nickel-manganese binary layered oxide for sodium-ion batteries.展开更多
Reversible protonic ceramic electrochemical cells(R-PCECs)demonstrate great feasibility for efficient energy storage and conversion.One critical challenge for the development of R-PCECs is the design of novel air elec...Reversible protonic ceramic electrochemical cells(R-PCECs)demonstrate great feasibility for efficient energy storage and conversion.One critical challenge for the development of R-PCECs is the design of novel air electrodes with the characteristics of high catalytic activity and acceptable durability.Here,we report a donor doping of Hf into the B-site of a cobalt-based double perovskite with a nominal formula of PrBa_(0.8)Ca_(0.2)Co_(1.9)Hf_(0.1)O_(5tδ)(PBCCHf_(0.1)),which is naturally reconfigured to a double perovskite PrBa_(0.8-x)Ca_(0.2)Co_(1.9)Hf_(0.1)-xO5tδ(PBCCHf_(0.1)-x)backbone and nano-sized BaHfO3(BHO)on the surface of PBCCHf_(0.1)x.The air electrode demonstrates enhanced catalytic activity and durability(a stable polarization resistance of 0.269Ωcm2 for~100 h at 600℃),due likely to the fast surface exchange process and bulk diffusion process.When employed as an air electrode of R-PCECs,a cell with PBCCHf_(0.1) air electrode demonstrates encouraging performances in modes of the fuel cell(FC)and electrolysis(EL)at 600℃:a peak power density of 0.998 W cm^(-2)and a current density of1.613 A cm^(-2)at 1.3 V(with acceptable Faradaic efficiencies).More importantly,the single-cell with PBCCHf_(0.1) air electrode demonstrates good cycling stability,switching back and forth from FC mode to EL mode0.5 A cm^(-2)for 200 h and 50 cycles.展开更多
Since 2019,research into MXene derivatives has seen a dramatic rise;further progress requires a rational design for specific functionality.Herein,through a molecular design by selecting suitable functional groups in t...Since 2019,research into MXene derivatives has seen a dramatic rise;further progress requires a rational design for specific functionality.Herein,through a molecular design by selecting suitable functional groups in the MXene coating,we have implemented the dual N doping of the derivatives,nitrogen-doped TiO_(2)@nitrogen-doped carbon nanosheets(N-TiO_(2)@NC),to strike a balance between the active anatase TiO_(2)at low temperatures,and carbon activation at high temperatures.The NH_(3)reduction environment generated at 400℃as evidenced by the in situ pyrolysis SVUV-PIMS process is crucial for concurrent phase engineering.With both electrical conductivity and surface Na+availability,the N-TiO_(2)@NC achieves higher interface capacitive-like sodium storage with long-term stability.More than 100 mAh g^(-1)is achieved at 2 A g^(-1)after 5000 cycles.The proposed design may be extended to other MXenes and solidify the growing family of MXene derivatives for energy storage.展开更多
Phase engineering has gained significant attention in energy-storage applications due to its ability to tailor the physicochemical properties and functionalities of electrode materials.In this study,we demonstrate the...Phase engineering has gained significant attention in energy-storage applications due to its ability to tailor the physicochemical properties and functionalities of electrode materials.In this study,we demonstrate the in-situ partial phase conversion of niobium pentoxide(Nb2O5),resulting in the formation of a monoclinic/orthorhombic(H/T-Nb2O5)heterophase homojunction.This study further confirms that the unique heterophase interface plays a crucial role in regulating the local electronic environment,resulting in charge redistribution,the formation of an internal electric field,and enhanced electron transfer.Moreover,the presence of abundant phase interfaces offers additional reactive sites for Li+ion adsorption,thereby enhancing reaction dynamics.The synergistic effects within the H/T-Nb2O5 homojunction are reflected in its high Li+storage capacity(413 mAh g^(−1) at 100 mA g^(−1)),superior rate capability,and cycling stability.Thus,this study demonstrates that the construction of heterophase homojunctions offers a promising strategy for developing high-performance anode materials for efficient Li-ion storage.展开更多
Gallium oxide(Ga_(2)O_(3)),with an ultrawide bandgap corresponding to the deep ultraviolet(DUV)spectra range,provides a potential subversive scheme for the filter-free DUV photodetection.Meanwhile,the various crystal ...Gallium oxide(Ga_(2)O_(3)),with an ultrawide bandgap corresponding to the deep ultraviolet(DUV)spectra range,provides a potential subversive scheme for the filter-free DUV photodetection.Meanwhile,the various crystal phases of Ga_(2)O_(3) provide more substrate options for achieving heteroepitaxy,with the coupling of Ga_(2)O_(3) to SiC substrates conducive to developing integrated Ga_(2)O_(3) DUV photodetectors.Phase engineering ofβ-Ga_(2)O_(3) andε-Ga_(2)O_(3) was achieved on the commercial 4H-SiC substrate via metal-organic chemical vapor deposition.According to the in-depth analysis of different Ga_(2)O_(3) growth stages,it was found thatβ-Ga_(2)O_(3) is easy to form under high-pressure growth conditions,while low-pressure conditions promote the formation ofε-Ga_(2)O_(3) at 500°C.Furthermore,the developedε-phase dominated Ga_(2)O_(3) DUV photodetector exhibits obvious advantages in high responsivity(∼639 A/W),photo-to-dark current ratio(∼2.4×10^(7)),external quantum efficiency(∼3.15×10^(5)%),and specific detectivity(∼9.62×10^(13) Jones)under 254 nm illumination.This work not only reveals the growth mechanism of Ga_(2)O_(3) films under various pressures but also ensures the great potential ofε-Ga_(2)O_(3) for highly sensitive DUV detection on the heterogeneous substrate,which is expected to expand the application of Ga_(2)O_(3) optoelectronic devices.展开更多
Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances ar...Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances are far from practical needs due to the lack of efficient electrocatalysts.Engineering the lattice of metal-based nanomaterials via phase control has emerged as an effective strategy to modulate their intrinsic electrocatalytic properties.Herein,we realize boron(B)-insertion-induced phase regulation of rhodium(Rh)nanocrystals to obtain amorphous Rh_(4)B nanoparticles(NPs)and hexagonal close-packed(hcp)RhB NPs through a facile wet-chemical method.A high Faradaic efficiency(92.1±1.2%)and NH_(3) yield rate(629.5±11.0μmol h^(−1) cm^(−2))are achieved over hcp RhB NPs,far superior to those of most reported NORR nanocatalysts.In situ spectro-electrochemical analysis and density functional theory simulations reveal that the excellent electrocatalytic performances of hcp RhB NPs are attributed to the upshift of d-band center,enhanced NO adsorption/activation profile,and greatly reduced energy barrier of the rate-determining step.A demonstrative Zn-NO battery is assembled using hcp RhB NPs as the cathode and delivers a peak power density of 4.33 mW cm−2,realizing simultaneous NO removal,NH3 synthesis,and electricity output.展开更多
Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of me...Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of metastable phases exhibit interesting properties. To obtain 2D TMDs with specific phases, it is important to develop phase engineering strategies including phase transition and phaseselective synthesis. Phase transition is a conventional method to transform one phase to another, while phase-selective synthesis means the direct fabrication of the target phases for2D TMDs. In this review, we introduce the structures and stability of 2D TMDs with different phases. Then, we summarize the detailed processes and mechanism of the traditional phase transition strategies. Moreover, in view of the increasing demand of high-phase purity TMDs, we present the advanced phase-selective synthesis strategies. Finally, we underline the challenges and outlooks of phase engineering of 2D TMDs in two aspects-high phase purity and excellent controllability. This review may promote the development of controllable phase engineering for 2D TMDs and even other2D materials toward both fundamental studies and practical applications.展开更多
The electrochemical CO_(2) reduction reaction(CO_(2)RR)offers a green and sustainable process to convert CO_(2) into valuable chemical stocks and fuels.Metal is one of the most promising types of catalysts to drive an...The electrochemical CO_(2) reduction reaction(CO_(2)RR)offers a green and sustainable process to convert CO_(2) into valuable chemical stocks and fuels.Metal is one of the most promising types of catalysts to drive an efficient and selective CO_(2)RR.The catalytic performance of metal nanocatalysts is strongly dependent on their structural features.Recently,phase engineering of nanomaterials(PEN)has emerged as a prominent tactic to regulate the catalytic performance of metal nanocatalysts for the CO_(2)RR.A broad range of metal nanocatalysts with conventional and unconventional crystal phases has been developed,and remarkable achievements have been made.This review summarizes the most recent developments in phase engineering of metal nanocatalysts for the electrochemical CO_(2)RR.We first introduce the different crystal phases of metal nanocatalysts used in the CO_(2)RR and then discuss various synthetic strategies for unconventional phases of metal nanocatalysts.After that,detailed discussions of metal nanocatalysts with conventional and unconventional phases,including amorphous phases,are presented.Finally,the challenges and perspectives in this emerging area are discussed.展开更多
The potential application of monolayer MS2(M?Mo,W)as thermoelectric material has been widely studied since the first report of successful fabrication.However,their performances are hindered by the considerable band ga...The potential application of monolayer MS2(M?Mo,W)as thermoelectric material has been widely studied since the first report of successful fabrication.However,their performances are hindered by the considerable band gap and the large lattice thermal conductivity in the pristine 2H phase.Recent discoveries of polymorphism in MS2s provide new opportunities for materials engineering.In this work,phonon and electron transport properties of both 2H and 1T0 phases were investigated by first-principle calculations.It is found that upon the phase transition from 2H to 1T0 in MS2,the electron transport is greatly enhanced,while the lattice thermal conductivity is reduced by several times.These features lead to a significant enhancement of power factor by one order of magnitude in MoS2 and by three times in WS2.Meanwhile,the figure of merit can reach up to 0.33 for 1T0eMoS2 and 0.68 for 1T0eWS2 at low temperature.These findings indicate that monolayer MS2 in the 1T0 phase can be promising materials for thermoelectric devices application.Meanwhile,this work demonstrates that phase engineering techniques can bring in one important control parameter in materials design.展开更多
The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries.Nevertheless,the broad application prospect is obstructed by ...The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries.Nevertheless,the broad application prospect is obstructed by the sluggish Na^(+)kinetics and the phase transitions upon cycling.Herein,we establish the thermodynamically stable phase diagram of various Mn-based oxide composites precisely controlled by sodium content tailoring strategy coupling with co-doping and solid-state reaction.The chemical environment of the P2/P'3 and P2/P3 biphasic composites indicate that the charge compensation mechanism stems from the cooperative contribution of anions and cations.Benefiting from the no phase transition to scavenge the structure strain,P2/P'3 electrode can deliver long cycling stability(capacity retention of 73.8%after 1000 cycles at 10 C)and outstanding rate properties(the discharge capacity of 84.08 mA h g^(-1)at 20 C)than P2/P3 electrode.Furthermore,the DFT calculation demonstrates that the introducing novel P'3 phase can significantly regulate the Na^(+)reaction dynamics and modify the local electron configuration of Mn.The effective phase engineering can provide a reference for designing other high-performance electrode materials for Na-ion batteries.展开更多
Imposing phase engineering to porous materials is promising to realize outperforming electrocatalytic performances by taking advantages of the merits of porous nanoarchitecture and heterophase structure.In this work,a...Imposing phase engineering to porous materials is promising to realize outperforming electrocatalytic performances by taking advantages of the merits of porous nanoarchitecture and heterophase structure.In this work,amorphous/crystalline ruthenium oxide(RuO_(2))porous particles with rationally regulated heterophases are successfully prepared by integrating the phase engineering into the porous material synthesis.The resultant defect-rich amorphous/crystalline RuO_(2)porous particles exhibit excellent electrocatalytic performance toward the oxygen evolution reaction,achieving a low overpotential of 165 mV at a current density of 10 mA·cm^(−2)and a high mass activity up to 133.8 mA·cm^(-2)at a low overpotential of 200 mV.This work indicates that the synergistic effect of amorphous/crystalline heterophase and porous structural characteristics enables RuO_(2)to trigger a superior electrocatalytic activity.展开更多
The phase transformation of catalysts has been extensively observed in heterogeneous catalytic reactions that hinder the long cycling catalysis,and it remains a big challenge to precisely control the active phase duri...The phase transformation of catalysts has been extensively observed in heterogeneous catalytic reactions that hinder the long cycling catalysis,and it remains a big challenge to precisely control the active phase during the complex conditions in electrochemical catalysis.Here,we theoretically predict that carbon-based support could achieve the phase engineering regulation of catalysts by suppressing specific phase transformation.Taken single-walled carbon nanotube(SWCNT)as typical support,combined with calculated E-pH(Pourbaix)diagram and advanced synchrotron-based characterizations technologies prove there are two different active phases source from cobalt selenide which demonstrate that the feasibility of using support effect regulating the potential advantageous catalysts.Moreover,it is worth noting that the phase engineering derived Co_(3)O_(4)-SWCNT exhibits a low overpotential of 201 mV for delivering the current density of 10 mA/cm^(2)in electrocatalytic oxygen evolution reaction(OER).Also,it reaches a record current density of 529 mA/cm^(2)at 1.63 V(vs.RHE)in the electrocatalytic urea oxidation reaction(UOR),overwhelming most previously reported catalysts.展开更多
With the ever-increasing demands of grid-scale energy storage,aqueous zinc-ion batteries(ZIBs)have garnered increasing attention around the world.However,limited Zn^(2+)host materials have hindered the commercializati...With the ever-increasing demands of grid-scale energy storage,aqueous zinc-ion batteries(ZIBs)have garnered increasing attention around the world.However,limited Zn^(2+)host materials have hindered the commercialization of ZIBs.Hence,Mo-V oxides with different phase structures(orth-,tri-,and tetra-MoVO)were precisely constructed to develop phase-dependent Mo-V oxide cathodes for Zn^(2+)storage in ZIBs.The open frameworks and varied tunnel structures formed a favorable alternative for achieving suitable Zn^(2+)diffusion kinetics.With optimized phase engineering,the high specific capacity of approximately 400 mA h g^(−1) and excellent cyclic stability of 1000 cycles were achieved with orth-MoVO as the cathode.The large amount of six-and seven-member rings in the orth-MoVO phase,which allow for alternative Zn^(2+)insertion,play a vital role in hosting Zn^(2+)ions reversibly.The proposed phase engineering strategy provides a new approach toward cathode design in ZIBs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.92365203,12534013,12174096,and 12474167)the Hunan Provincial Science Fund for Distinguished Young Scholars(Grant No.2022JJ10060)+1 种基金the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)the Science Fund for Self-initiated Innovation of NUDT。
文摘The two-dimensional van der Waals layered semiconductor In_(2)Se_(3) has emerged as a promising candidate for non-volatile ferroelectric memory,optoelectronic devices,and polymorphic phase engineering.Polymorphic In_(2)Se_(3) typically stabilizes in three distinct phases:α-,β′-,and β^(*)-In_(2)Se_(3),each dominant within specific temperature ranges.Although the crystal structures and ferroelectric properties of these phases have been widely studied,the unambiguous assignment of their in-plane and out-of-plane ferroelectric behaviors,as well as the mechanisms governing their phase transitions,remains a subject of active debate.In this study,we investigate the evolution of atomic and electronic structures in molecular beam epitaxy-grown ultrathin In_(2)Se_(3) films through correlated microstructural and macroscopic physical property analysis.By employing scanning tunneling microscopy/spectroscopy,temperature-dependent Raman spectroscopy,and piezoresponse force microscopy,we demonstrate a reversible temperature-induced phase transition between the in-plane ferroelectric β^(*)and antiferroelectric β′phases.Furthermore,we confirm robust out-of-plane ferroelectric polarization in the as-grown films and achieve an electric-field-driven transition from the β^(*)to β′phase.Our findings not only advance the fundamental understanding of phase transitions and polarization evolution in two-dimensional semiconductors but also open new avenues for the design of tunable,non-volatile ferroelectric memory devices.
基金supported by Shenzhen Fundamental Research Program(No.GXWD20201231165807007-20200802205241003).
文摘Aqueous iron-ion batteries are regarded as one of the most promising candidates for grid applications owing to their low cost,high theoretical capacity,and excellent stability of iron in aqueous electrolytes.However,the slow Fe(de)insertion caused by the high polarity of Fe^(2+)makes it difficult to match suitable cathode materials.Herein,defect-rich MoS_(2)with abundant 1T phase is synthesized and successfully applied in aqueous iron-ion batteries.Benefit from abundant active sites generated by the heteroatom incorporation and S vacancy,as well as the highly conductive 1T phase,it can deliver a specific capacity of 123 mAh/g at a current density of 100mA/g,and demonstrates an impressive capacity retention of 88%after 600 cycles at 200mA/g.This work presents a novel pathway for the advancement of cathode materials for aqueous iron-ion batteries.
基金This work was financially supported by the National Natural Science Foundation of China(U21A2093 and 52102370)the Natural Science Foundation of Shaanxi Province(2022JM-260)+2 种基金the Shanghai Key Laboratory of R&D for Metallic Functional Materials(2021-01)and Open Fund of Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province(JBGS014)Open access funding provided by Shanghai Jiao Tong University
文摘Precisely reducing the size of metal-organic frameworks(MOFs)derivatives is an effective strategy to manipulate their phase engineering owing to size-dependent oxidation;however,the underlying relationship between the size of derivatives and phase engineering has not been clarified so far.Herein,a spatial confined growth strategy is proposed to encapsulate small-size MOFs derivatives into hollow carbon nanocages.It realizes that the hollow cavity shows a significant spatial confinement effect on the size of confined MOFs crystals and subsequently affects the dielectric polarization due to the phase hybridization with tunable coherent interfaces and heterojunctions owing to size-dependent oxidation motion,yielding to satisfied microwave attenuation with an optimal reflection loss of-50.6 d B and effective bandwidth of 6.6 GHz.Meanwhile,the effect of phase hybridization on dielectric polarization is deeply visualized,and the simulated calculation and electron holograms demonstrate that dielectric polarization is shown to be dominant dissipation mechanism in determining microwave absorption.This spatial confined growth strategy provides a versatile methodology for manipulating the size of MOFs derivatives and the understanding of size-dependent oxidation-induced phase hybridization offers a precise inspiration in optimizing dielectric polarization and microwave attenuation in theory.
基金the National Natural Science Foundation of China(No.51672222)Joint Fund Project-Enterprise-Shaanxi Coal Joint Fund Project(2019JLM-32)+2 种基金Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX202054)the Graduate innovation team of Northwestern Polytechnical Universitythe Analysis and Testing Center of Northwestern Polytechnical University for their technical assistance in SEM(Verios G4).
文摘Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of different phases on the EMW absorbing performance,such as 1T and 2H phase,is still not studied.In this work,micro-1T/2H MoS_(2) is achieved via a facile one-step hydrother-mal route,in which the 1T phase is induced by the intercalation of vip molecules and ions.The EMW absorption mechanism of single MoS_(2) is revealed by presenting a comparative study between 1T/2H MoS_(2) and 2H MoS_(2).As a result,1T/2H MoS_(2) with the matrix loading of 15%exhibits excellent microwave absorption property than 2H MoS_(2).Furthermore,taking the advantage of 1T/2H MoS_(2),a flexible EMW absorbers that ultrathin 1T/2H MoS_(2)grown on the carbon fiber also performs outstanding performance only with the matrix loading of 5%.This work offers necessary reference to improve microwave absorption performance by phase engineering and design a new type of flexible electromagnetic wave absorption material to apply for the portable microwave absorption electronic devices.
基金National Natural Science Foundation of China,Grant/Award Numbers:U2004172,51972287 and 51502269the Foundation for University Key Teachers of Henan Province,Grant/Award Number:2020GGJS009Natural Science Foundation of Henan Province,Grant/Award Number:202300410368。
文摘Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase to the 1T phase has been proven to be a significant method to improve the catalytic activity.However,precisely controllable phase engineering of MoSe_(2) has rarely been reported.Herein,by in situ Li ions intercalation in MoSe_(2),a precisely controllable phase evolution from 2H-MoSe_(2) to 1T-MoSe_(2) was realized.More importantly,the definite functional relationship between cut-off voltage and phase structure was first identified for phase engineering through in situ observation and modulation methods.The sulfur host(CNFs/1T-MoSe_(2))presents high charge density,strong polysulfides adsorption,and catalytic kinetics.Moreover,Li-S cells based on it display capacity retention of 875.3mAh g^(-1) after 500 cycles at 1 C and an areal capacity of 8.71mAh cm^(-2) even at a high sulfur loading of 8.47mg cm^(-2).Furthermore,the flexible pouch cell exhibiting decent performance will endow a promising potential in the wearable energy storage field.This study proposes an effective strategy to precisely control the phase structure of MoSe_(2),which may provide the reference to fabricate the highly efficient electrocatalysts for LSBs and other energy systems.
基金the financial support by Natural Science Foundation of Jiangsu Province(No.BK20210827)China Postdoctoral Science Foundation(No.2021M700117)+3 种基金National Natural Science Foundation of China(Nos.U1904215 and 41977085)Program for Young Changjiang Scholars of the Ministry of Education(No.Q2018270)Six Talent Peaks Project in Jiangsu Province(No.TD-JNHB-012)333 Project in Jiangsu Province(No.BRA2020300).
文摘In this work,taking NiSe_(2)as a prototype to be used as cocatalyst in photocatalytic hydrogen evolution,we demonstrate that the crystal phase of NiSe_(2)plays a vital role in determining the catalytic stability,rather than activity.Theoretical and experimental results indicate that the phase structure shows negligible influence to the charge transport and hydrogen adsorption capacity.When integrating with carbon nitride(CN)photocatalyst forming hybrids(m-NiSe_(2)/CN and p-NiSe_(2)/CN),the hybrids show comparable photocatalytic hydrogen evolution rates(3.26μmol/h and 3.75μmol/h).Unlike the comparable catalytic activity,we found that phase-engineered NiSe_(2)exhibits distinct stability,i.e.,m-NiSe_(2)can evolve H_(2) steadily,but p-NiSe_(2)shows a significant decrease in catalytic process(∼57.1%decrease in 25 h).The factor leading to different catalytic stability can be ascribed to the different surface conversion behavior during photocatalytic process,i.e.,chemical structure of m-NiSe_(2)can be well preserved in catalytic process,but partial p-NiSe_(2)tends to be converted to NiOOH.
基金financially supported by the Key Grant for Special Professors in Jiangsu Province(No.RK030STP18001)the Scientific Research Foundation of Nanjing University of Posts and Telecommunications(No.NY218150)“1311 Talents Program”of Nanjing University of Posts and Telecommunications and the National Postdoctoral Program for Innovative Talents(No.BX20190156)。
文摘Hydrogen(H2)is considered to be a promising substitute for fossil fuels.Two-dimensional(2D)nanomaterials have exhibited an efficient electrocatalytic capacity to catalyze hydrogen evolution reaction(HER).Particularly,phase engineering of 2D nanomaterials is opening a novel research direction to endow 2D nanostructures with fascinating properties for deep applications in catalyzing HER.In this review,we briefly summarize the research progress and present the current challenges on phase engineering of 2D nanomaterials for their applications in electrocatalytic HER.Our summary will be of significance to provide fundamental understanding for designing novel 2D nanomaterials with unconventional phases to electrochemically catalyze HER.
基金supported by project from the National Natural Science Foundation of China(21805018)by the Sichuan Science and Technology Program(2022ZHCG0018,2023NSFSC0117,2023ZHCG0060)+1 种基金the Yibin Science and Technology Program(2022JB005)project funded by the China Postdoctoral Science Foundation(2022M722704)。
文摘Nickel-manganese binary layered oxides with high working potential and low cost are potential candidates for sodium-ion batteries,but their electrochemical properties are highly related to compositional diversity.Diverse composite materials with various phase structures of P3,P2/P3,P2,P2/O3,and P2/P3/O3 were synthesized by manipulating the sodium content and calcination conditions,leading to the construction of a synthetic phase diagram for Na_(x)Ni_(0.25)Mn_(0.75)O_(2)(0.45≤x≤1.1).Then,we compared the electrochemical characteristics and structural evolution during the desodiation/sodiation process of P2,P2/P3,P2/03,and P2/P3/O3-Na_(x)Ni_(0.25)Mn_(0.75)O_(2).Among them,P2/P3-Na0.75Ni0.25Mn0.75O2exhibits the best rate capability of 90.9 mA h g^(-1)at 5 C,with an initial discharge capacity of 142.62 mA h g^(-1)at 0.1 C and a capacity retention rate of 78.25%after 100 cycles at 1 C in the voltage range of 2-4.3 V.The observed superior sodium storage performance of P2/P3 hybrids compared to other composite phases can be attributed to the enhanced Na^(+)transfer dynamic,reduction of the Jahn-teller effect,and improved reaction reversibility induced by the synergistic effect of P2 and P3 phases.The systematic research and exploration of phases in Na_(x)Ni_(0.25)Mn_(0.75)O_(2)provide new sights into high-performance nickel-manganese binary layered oxide for sodium-ion batteries.
基金the financial support from the National Natural Science Foundation of China(Nos.22179039)the Introduced Innovative R&D Team of Guangdong(No.2021ZT09L392)+3 种基金the Fundamental Research Funds for the Central Universities(2022ZYGXZR002)Zijin Mining Group Co.,Ltd(5405-ZC-2023-00008)the Pearl River Talent Recruitment Program(2019QN01C693)the Natural Science Foundation of Guangdong Province(No.2022A1515011785).
文摘Reversible protonic ceramic electrochemical cells(R-PCECs)demonstrate great feasibility for efficient energy storage and conversion.One critical challenge for the development of R-PCECs is the design of novel air electrodes with the characteristics of high catalytic activity and acceptable durability.Here,we report a donor doping of Hf into the B-site of a cobalt-based double perovskite with a nominal formula of PrBa_(0.8)Ca_(0.2)Co_(1.9)Hf_(0.1)O_(5tδ)(PBCCHf_(0.1)),which is naturally reconfigured to a double perovskite PrBa_(0.8-x)Ca_(0.2)Co_(1.9)Hf_(0.1)-xO5tδ(PBCCHf_(0.1)-x)backbone and nano-sized BaHfO3(BHO)on the surface of PBCCHf_(0.1)x.The air electrode demonstrates enhanced catalytic activity and durability(a stable polarization resistance of 0.269Ωcm2 for~100 h at 600℃),due likely to the fast surface exchange process and bulk diffusion process.When employed as an air electrode of R-PCECs,a cell with PBCCHf_(0.1) air electrode demonstrates encouraging performances in modes of the fuel cell(FC)and electrolysis(EL)at 600℃:a peak power density of 0.998 W cm^(-2)and a current density of1.613 A cm^(-2)at 1.3 V(with acceptable Faradaic efficiencies).More importantly,the single-cell with PBCCHf_(0.1) air electrode demonstrates good cycling stability,switching back and forth from FC mode to EL mode0.5 A cm^(-2)for 200 h and 50 cycles.
基金financially supported by the National Key R&D Program of China(2021YFA1501502)National Natural Science Foundation of China(22075263,52002366)+2 种基金Fundamental Research Funds for the Central Universities(WK2060000039)USTC Research Funds(KY2060000165,GG2060007008)Natural Science Foundation of Jiangsu Province(BK20200386)
文摘Since 2019,research into MXene derivatives has seen a dramatic rise;further progress requires a rational design for specific functionality.Herein,through a molecular design by selecting suitable functional groups in the MXene coating,we have implemented the dual N doping of the derivatives,nitrogen-doped TiO_(2)@nitrogen-doped carbon nanosheets(N-TiO_(2)@NC),to strike a balance between the active anatase TiO_(2)at low temperatures,and carbon activation at high temperatures.The NH_(3)reduction environment generated at 400℃as evidenced by the in situ pyrolysis SVUV-PIMS process is crucial for concurrent phase engineering.With both electrical conductivity and surface Na+availability,the N-TiO_(2)@NC achieves higher interface capacitive-like sodium storage with long-term stability.More than 100 mAh g^(-1)is achieved at 2 A g^(-1)after 5000 cycles.The proposed design may be extended to other MXenes and solidify the growing family of MXene derivatives for energy storage.
基金financial support from the National Natural Science Foundation of China(22250410272 and 21706103)the Natural Science Foundation of Jiangsu Province(BK20170549).
文摘Phase engineering has gained significant attention in energy-storage applications due to its ability to tailor the physicochemical properties and functionalities of electrode materials.In this study,we demonstrate the in-situ partial phase conversion of niobium pentoxide(Nb2O5),resulting in the formation of a monoclinic/orthorhombic(H/T-Nb2O5)heterophase homojunction.This study further confirms that the unique heterophase interface plays a crucial role in regulating the local electronic environment,resulting in charge redistribution,the formation of an internal electric field,and enhanced electron transfer.Moreover,the presence of abundant phase interfaces offers additional reactive sites for Li+ion adsorption,thereby enhancing reaction dynamics.The synergistic effects within the H/T-Nb2O5 homojunction are reflected in its high Li+storage capacity(413 mAh g^(−1) at 100 mA g^(−1)),superior rate capability,and cycling stability.Thus,this study demonstrates that the construction of heterophase homojunctions offers a promising strategy for developing high-performance anode materials for efficient Li-ion storage.
基金supported by the National Key Research and Development Program of China(2023YFB3610200 and 2024YFA1208800)the National Natural Science Foundation of China(61925110,U20A20207,62304215,and 62171426)+2 种基金the University of Science and Technology of China(WK2100000025,YD2100002009,YD2100002010,and YD2100002007)the China Postdoctoral Science Foundation(2023M733367)the CAS Project for Young Scientists in Basic Research(YSBR-029)。
文摘Gallium oxide(Ga_(2)O_(3)),with an ultrawide bandgap corresponding to the deep ultraviolet(DUV)spectra range,provides a potential subversive scheme for the filter-free DUV photodetection.Meanwhile,the various crystal phases of Ga_(2)O_(3) provide more substrate options for achieving heteroepitaxy,with the coupling of Ga_(2)O_(3) to SiC substrates conducive to developing integrated Ga_(2)O_(3) DUV photodetectors.Phase engineering ofβ-Ga_(2)O_(3) andε-Ga_(2)O_(3) was achieved on the commercial 4H-SiC substrate via metal-organic chemical vapor deposition.According to the in-depth analysis of different Ga_(2)O_(3) growth stages,it was found thatβ-Ga_(2)O_(3) is easy to form under high-pressure growth conditions,while low-pressure conditions promote the formation ofε-Ga_(2)O_(3) at 500°C.Furthermore,the developedε-phase dominated Ga_(2)O_(3) DUV photodetector exhibits obvious advantages in high responsivity(∼639 A/W),photo-to-dark current ratio(∼2.4×10^(7)),external quantum efficiency(∼3.15×10^(5)%),and specific detectivity(∼9.62×10^(13) Jones)under 254 nm illumination.This work not only reveals the growth mechanism of Ga_(2)O_(3) films under various pressures but also ensures the great potential ofε-Ga_(2)O_(3) for highly sensitive DUV detection on the heterogeneous substrate,which is expected to expand the application of Ga_(2)O_(3) optoelectronic devices.
基金funding support from General Research Fund[Project No.14300525]from the Research Grants Council(RGC)of Hong Kong SAR,Chinafunding support from Natural Science Foundation of China(NSFC)Young Scientists Fund(Project No.22305203)+2 种基金NSFC Projects Nos.22309123,22422303,22303011,22033002,92261112 and U21A20328support from the Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM)at City University of Hong Kongsupport from Young Collaborative Research Grant[Project No.C1003-23Y]support from RGC of Hong Kong SAR,China.
文摘Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances are far from practical needs due to the lack of efficient electrocatalysts.Engineering the lattice of metal-based nanomaterials via phase control has emerged as an effective strategy to modulate their intrinsic electrocatalytic properties.Herein,we realize boron(B)-insertion-induced phase regulation of rhodium(Rh)nanocrystals to obtain amorphous Rh_(4)B nanoparticles(NPs)and hexagonal close-packed(hcp)RhB NPs through a facile wet-chemical method.A high Faradaic efficiency(92.1±1.2%)and NH_(3) yield rate(629.5±11.0μmol h^(−1) cm^(−2))are achieved over hcp RhB NPs,far superior to those of most reported NORR nanocatalysts.In situ spectro-electrochemical analysis and density functional theory simulations reveal that the excellent electrocatalytic performances of hcp RhB NPs are attributed to the upshift of d-band center,enhanced NO adsorption/activation profile,and greatly reduced energy barrier of the rate-determining step.A demonstrative Zn-NO battery is assembled using hcp RhB NPs as the cathode and delivers a peak power density of 4.33 mW cm−2,realizing simultaneous NO removal,NH3 synthesis,and electricity output.
基金supported by the National Natural Science Foundation of China (21673161 and 21473124)the Science and Technology Department of Hubei Province (2017AAA114)the Sino-German Center for Research Promotion (1400)
文摘Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of metastable phases exhibit interesting properties. To obtain 2D TMDs with specific phases, it is important to develop phase engineering strategies including phase transition and phaseselective synthesis. Phase transition is a conventional method to transform one phase to another, while phase-selective synthesis means the direct fabrication of the target phases for2D TMDs. In this review, we introduce the structures and stability of 2D TMDs with different phases. Then, we summarize the detailed processes and mechanism of the traditional phase transition strategies. Moreover, in view of the increasing demand of high-phase purity TMDs, we present the advanced phase-selective synthesis strategies. Finally, we underline the challenges and outlooks of phase engineering of 2D TMDs in two aspects-high phase purity and excellent controllability. This review may promote the development of controllable phase engineering for 2D TMDs and even other2D materials toward both fundamental studies and practical applications.
基金support from the Start-up Fund(BDC2)and Research Institute for Advanced Manufacturing(RIAM)Fund(CD4D)from the Hong Kong Polytechnic University.Y.C.thanks the support from Start-up Fund(Project No.4930977)the Direct Grant for Research(Project No.4053444)from the Chinese University of Hong Kong+3 种基金H.Z.thanks the support from ITC via the Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM),the Research Grants Council of Hong Kong(GRF Project No.11301721)the Start-Up Grant(Project No.9380100)the grants(Project Nos.7020054,9678272,and 1886921)from the City University of Hong Kongthe Science Technology and Innovation Committee of Shenzhen Municipality(“Preparation of single atoms on transition metal chalcogenides for electrolytic hydrogen evolution”,CityU),and the Project 52131301 supported by NSFC.
文摘The electrochemical CO_(2) reduction reaction(CO_(2)RR)offers a green and sustainable process to convert CO_(2) into valuable chemical stocks and fuels.Metal is one of the most promising types of catalysts to drive an efficient and selective CO_(2)RR.The catalytic performance of metal nanocatalysts is strongly dependent on their structural features.Recently,phase engineering of nanomaterials(PEN)has emerged as a prominent tactic to regulate the catalytic performance of metal nanocatalysts for the CO_(2)RR.A broad range of metal nanocatalysts with conventional and unconventional crystal phases has been developed,and remarkable achievements have been made.This review summarizes the most recent developments in phase engineering of metal nanocatalysts for the electrochemical CO_(2)RR.We first introduce the different crystal phases of metal nanocatalysts used in the CO_(2)RR and then discuss various synthetic strategies for unconventional phases of metal nanocatalysts.After that,detailed discussions of metal nanocatalysts with conventional and unconventional phases,including amorphous phases,are presented.Finally,the challenges and perspectives in this emerging area are discussed.
基金the Jiangsu provincial natural science funding Project(No.BK20160308)the NSF of Heilongjiang Province of China under Grants No.QC2015001.
文摘The potential application of monolayer MS2(M?Mo,W)as thermoelectric material has been widely studied since the first report of successful fabrication.However,their performances are hindered by the considerable band gap and the large lattice thermal conductivity in the pristine 2H phase.Recent discoveries of polymorphism in MS2s provide new opportunities for materials engineering.In this work,phonon and electron transport properties of both 2H and 1T0 phases were investigated by first-principle calculations.It is found that upon the phase transition from 2H to 1T0 in MS2,the electron transport is greatly enhanced,while the lattice thermal conductivity is reduced by several times.These features lead to a significant enhancement of power factor by one order of magnitude in MoS2 and by three times in WS2.Meanwhile,the figure of merit can reach up to 0.33 for 1T0eMoS2 and 0.68 for 1T0eWS2 at low temperature.These findings indicate that monolayer MS2 in the 1T0 phase can be promising materials for thermoelectric devices application.Meanwhile,this work demonstrates that phase engineering techniques can bring in one important control parameter in materials design.
基金supported by the National Natural Science Foundation of China (52173273)Fundamental Research Funds for the Central Universities (2022CX11013)+2 种基金Shanxi Province Science Foundation for Youths (No.202203021212391)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (No.2022L253)Institute Foundation Project of China Academy of Railway Sciences Corporation Limited Metals and Chemistry Research Institute (No.2023SJ02)。
文摘The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries.Nevertheless,the broad application prospect is obstructed by the sluggish Na^(+)kinetics and the phase transitions upon cycling.Herein,we establish the thermodynamically stable phase diagram of various Mn-based oxide composites precisely controlled by sodium content tailoring strategy coupling with co-doping and solid-state reaction.The chemical environment of the P2/P'3 and P2/P3 biphasic composites indicate that the charge compensation mechanism stems from the cooperative contribution of anions and cations.Benefiting from the no phase transition to scavenge the structure strain,P2/P'3 electrode can deliver long cycling stability(capacity retention of 73.8%after 1000 cycles at 10 C)and outstanding rate properties(the discharge capacity of 84.08 mA h g^(-1)at 20 C)than P2/P3 electrode.Furthermore,the DFT calculation demonstrates that the introducing novel P'3 phase can significantly regulate the Na^(+)reaction dynamics and modify the local electron configuration of Mn.The effective phase engineering can provide a reference for designing other high-performance electrode materials for Na-ion batteries.
文摘Imposing phase engineering to porous materials is promising to realize outperforming electrocatalytic performances by taking advantages of the merits of porous nanoarchitecture and heterophase structure.In this work,amorphous/crystalline ruthenium oxide(RuO_(2))porous particles with rationally regulated heterophases are successfully prepared by integrating the phase engineering into the porous material synthesis.The resultant defect-rich amorphous/crystalline RuO_(2)porous particles exhibit excellent electrocatalytic performance toward the oxygen evolution reaction,achieving a low overpotential of 165 mV at a current density of 10 mA·cm^(−2)and a high mass activity up to 133.8 mA·cm^(-2)at a low overpotential of 200 mV.This work indicates that the synergistic effect of amorphous/crystalline heterophase and porous structural characteristics enables RuO_(2)to trigger a superior electrocatalytic activity.
基金the National Key R&D Program of China(Nos.2020YFA0405800 and 2017YFA0303500)the National Natural Science Foundation of China(NSFC)(Nos.U1932201,U2032113,and 22075264)+3 种基金CAS Collaborative Innovation Program of Hefei Science Center(Nos.2019HSC-CIP002 and 2020HSC-CIP002)USTC Research Funds of the Double First-Class Initiative(No.YD2310002003)Institute of Energy,Hefei Comprehensive Nation Science Center,University Synergy Innovation Program of Anhui Province(GXXT-2020-002)CAS Iterdisciplinary Innovation Team.L.S.acknowledges the support from Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University(111 project,B12015)。
文摘The phase transformation of catalysts has been extensively observed in heterogeneous catalytic reactions that hinder the long cycling catalysis,and it remains a big challenge to precisely control the active phase during the complex conditions in electrochemical catalysis.Here,we theoretically predict that carbon-based support could achieve the phase engineering regulation of catalysts by suppressing specific phase transformation.Taken single-walled carbon nanotube(SWCNT)as typical support,combined with calculated E-pH(Pourbaix)diagram and advanced synchrotron-based characterizations technologies prove there are two different active phases source from cobalt selenide which demonstrate that the feasibility of using support effect regulating the potential advantageous catalysts.Moreover,it is worth noting that the phase engineering derived Co_(3)O_(4)-SWCNT exhibits a low overpotential of 201 mV for delivering the current density of 10 mA/cm^(2)in electrocatalytic oxygen evolution reaction(OER).Also,it reaches a record current density of 529 mA/cm^(2)at 1.63 V(vs.RHE)in the electrocatalytic urea oxidation reaction(UOR),overwhelming most previously reported catalysts.
基金supported by Guangdong Natural Science Foundation(2019A1515010675)the Science and Technology Project of Shenzhen(JCYJ20180305125106329,KQJSCX20180328094001794)。
文摘With the ever-increasing demands of grid-scale energy storage,aqueous zinc-ion batteries(ZIBs)have garnered increasing attention around the world.However,limited Zn^(2+)host materials have hindered the commercialization of ZIBs.Hence,Mo-V oxides with different phase structures(orth-,tri-,and tetra-MoVO)were precisely constructed to develop phase-dependent Mo-V oxide cathodes for Zn^(2+)storage in ZIBs.The open frameworks and varied tunnel structures formed a favorable alternative for achieving suitable Zn^(2+)diffusion kinetics.With optimized phase engineering,the high specific capacity of approximately 400 mA h g^(−1) and excellent cyclic stability of 1000 cycles were achieved with orth-MoVO as the cathode.The large amount of six-and seven-member rings in the orth-MoVO phase,which allow for alternative Zn^(2+)insertion,play a vital role in hosting Zn^(2+)ions reversibly.The proposed phase engineering strategy provides a new approach toward cathode design in ZIBs.
