Co_(3)O_(4) is a promising catalyst for the chlorine evolution reaction(CER)in seawater;however,its CER selectivity is compromised by the adsorption of the competitive oxygen evolution reaction intermediate(OH^(-))at ...Co_(3)O_(4) is a promising catalyst for the chlorine evolution reaction(CER)in seawater;however,its CER selectivity is compromised by the adsorption of the competitive oxygen evolution reaction intermediate(OH^(-))at Co sites.Inspired by the hard-soft acid-base(HSAB)theory,this study proposes incorporating early transition metal sites(V)with a low degree of electron delocalization into Co_(3)O_(4) to modulate the selective adsorption of reactants on catalytic sites.Experimental and theoretical calculations reveal that V incorporation facilitates the electron accumulation at the Co site,significantly strengthening the interaction between Co and Cl^(-).Meanwhile,the loss of electrons from V sites generates a more localized electronic state that preferentially adsorbs OH^(-),thus reducing the Co-OH interaction and releasing more Co sites for Cl^(-)adsorption.Therefore,Co_(2)VO_(4) exhibits a high CER selectivity of 92.3%and maintains one of the highest stabilities over 300 h in natural seawater.The resulting half-flow cell achieves~100%disinfection efficiency in seawater,validating the HSAB theory-based design strategy and offering new guidance for developing highly selective seawater CER catalysts.展开更多
In order to maximize the advantages of high energy density in Li metal batteries,it is necessary to match cathode materials with high specific capacities.Ni-rich layered oxides have been shown to reversibly embed more...In order to maximize the advantages of high energy density in Li metal batteries,it is necessary to match cathode materials with high specific capacities.Ni-rich layered oxides have been shown to reversibly embed more Li+during charge and discharge processes due to the increased Ni content in their crystal structure,thereby providing higher energy density.However,a significant challenge associated with Ni-rich layered oxide cathodes is the crossover effect,which arises from the dissolution of Ni^(2+)from the cathode,leading to a rapid decline in battery capacity.Through the delocalization-induced effect of solvent molecules,Ni^(2+)is transformed into a fluorinated transition metal inorganic phase layer,thereby forming a corrosion-resistant Li metal interface.This prevents solvent molecules from being reduced and degraded by Li metal anode.The surface of the Li metal anode exhibits a smooth and flat deposition morphology after long-term cycling.Furthermore,the introduction of Ni^(2+)can enhance the concentration gradient of transition metal ions near the cathode,thereby suppressing the dissolution process of transition metal ions.Even the NCM955 cathode with a mass load of 22 mg cm^(−2)also has great capacity retention after cycling.The Ni^(2+)induced by high electronegative functional groups of solvent under the electron delocalization effect,preventing the Ni ions dissolution of cathode and constructing a corrosion-resistant Li metal interface layer.This work provides new insights into suppressing crossover effects in Li metal batteries with high nickel cathodes.展开更多
Polysynthetic twinned(PST)TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength,ductility and creep resistance.However,a critical property for hi...Polysynthetic twinned(PST)TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength,ductility and creep resistance.However,a critical property for high-temperature application of such material involving high-temperature fatigue properties remains unknown.Here,the high-temperature high-cycle fatigue performance of PST TiAl single crystal has been studied.The result shows that PST TiAl single crystal can withstand more than 107 cyclic loadings at 975℃ under a stress amplitude of 270 MPa,which is significantly higher than traditional TiAl alloys.Experimental observations and atomistic simulations indicate that the improvement of fatigue resistance is attributed to the plastic strain delocalization in uniform lamellar structure,and the plastic deformation is well-distributed and sufficient in each lamella.Even in theα2 lamella with difficult slippage,a large number of stacking fault structures can be observed.The{c+a}dislocations inα2 tend to dissociate into a Frank partial with b=1/6<2^(-)20^(-)3>,forming a ribbon of I1 fault which ensures the continuity of deformation.展开更多
Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to des...Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to design Fe-N-Cs with increased active species content,surface area,and electronic conductivity,their performance is still far from satisfactory.Hitherto,there is limited research about regulation on the electronic spin states of Fe centers for Fe-N-Cs electrocatalysts to improve their catalytic performance.Here,we introduce Ti_(3)C_(2) MXene with sulfur terminals to regulate the electronic configuration of FeN_(4) species and dramatically enhance catalytic activity toward ORR.The MXene with sulfur terminals induce the spin-state transition of FeN_(4) species and Fe 3d electron delocalization with d band center upshift,enabling the Fe(II)ions to bind oxygen in the end-on adsorption mode favorable to initiate the reduction of oxygen and boosting oxygen-containing groups adsorption on FeN_(4) species and ORR kinetics.The resulting FeN_(4)-Ti_(3)C_(2)Sx exhibits comparable catalytic performance to those of commercial Pt-C.The developed wearable ZABs using FeN_(4)-Ti_(3)C_(2)Sx also exhibit fast kinetics and excellent stability.This study confirms that regulation of the electronic structure of active species via coupling with their support can be a major contributor to enhance their catalytic activity.展开更多
Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the ...Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the strong interactions between the high-polarized bivalent Mg^(2+)ions and anionic lattice.Herein,we design and propose a hetero-structural VO_(2)(R)-VS_(4)cathode,in which the re-delocalized d-electrons can effectively shield the polarity of Mg^(2+)ions.Theoretically,the electrons should spontaneously transfer from VS_(4)to VO_(2)(R)through the interfaces of hetero-structure due to the lower work function value of VS_(4).Furthermore,the internal electrons transfer lead to the electronic injection into VO_(2)(R)from VS_(4)and the partially broken V-V dimers,indicating the presence of lone pair electrons and charge re-delocalization.Benefiting from the shield effect of re-delocalized electrons,and the weakened attraction between cations and O/S anions enables more S^(2-)-S_(2)^(2-)redox groups to participate the electrochemical reactions and compensate the double charge of Mg^(2+)ions.Accordingly,VO_(2)(R)-VS_(4)hetero-structure exhibits a high specific capacity of 554 mA h g^(-1)at 50 mA g^(-1).It is believed that the charge re-delocalization of cathode extremely boost the Mg^(2+)ions migration for the high-capacity of MIBs.展开更多
We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the loc...We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the localization length is enhanced by disorder of side sites in the case of strong disorder, but in the case of weak disorder there is a plateau in this dependence. The above behaviour is the conjunct influence of the coupling to the surrounding atoms and the antiresonant effect. We also discuss different effects and their physical origin of different types of disorder in such systems. The numerical results show that coupling with the surrounding atoms can induce either the localization or delocalization effect depending on the values of parameters.展开更多
Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals ...Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals （Ir, Pt, and Au） and 4d metals （Ru, Rh, and Pd） were prepared and capped with ethynylphenylacetylene and the impacts of the number of metal d electrons on the nanoparticle optoelectronic properties were examined. Both FTIR and photoluminescence measurements indicate that intraparticle charge delocalization was en- hanced with the increase of the number of d electrons in the same period with palladium being an exception.展开更多
The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds w...The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).展开更多
Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was c...Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.展开更多
Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trif...Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trifluorostyrenes(Y-TFS's). A series of previously unavailable Y-TFS's were thus obtained.展开更多
We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transpo...We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transport dynamics in the two-photon CCA exhibits the entanglement-enhanced two-photon delocalization phenomenon. It is shown that the CCA can realize the localization-to-delocalization transition for two entangled photons.展开更多
Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer a...Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer and distribution of photogenerated carriers during the reduction process in this intricate system and deciphering the role of activated groups in promoting reduction efficiency.In this study,we strategically regulate the structure of polymeric carbon nitride to promote the N-doped state,thereby facilitating delocalization electron enrichment.The resulting active sites effectively activate peroxyl disulfate(PDS),generating radicals that expedite the selective reduction of U(VI).This strategic approach mitigates the inherent disadvantage of the short half-life of free radicals in persulfate-based advanced oxidation processes.As a consequence of our endeavors and with the simultaneous presence of PDS and hydrogen peroxide,we achieve an exceptional photoreduction efficiency of 100%within a remarkably short period of 20 min.This breakthrough presents a high-efficiency application with significant potential for addressing the pollution associated with uranylcontaining wastewater.Our findings not only contribute to the fundamental understanding of AOPs but also offer a practical solution with implications for environmental remediation.展开更多
Achieving high electrical conductivity through doping without compromising the Seebeck coefficient remains a fundamental challenge in organic thermoelectrics,owing to the intrinsic trade-off between the two parameters...Achieving high electrical conductivity through doping without compromising the Seebeck coefficient remains a fundamental challenge in organic thermoelectrics,owing to the intrinsic trade-off between the two parameters.Here,we propose a rational molecular design strategy to enhance the charge delocalization by substituting thiophene with selenophene in donor-acceptor(D-A)type of conjugated polymers based on benzo[1,2-b:4,5-b']dithiophene(BDT)and diketone-functionalized benzo[1,2-c:4,5-c']dithiophene(BDD)units.The selenophene substitution,combined with backbone planarization via a phenyl substituent,increases the charge localization length from~7 nm to~11.5 nm.These structural modifications result in a significant improvement of electrical conductivity,from~78 S cm^(-1)to~148 S cm^(-1),while maintaining a high Seebeck coefficient,leading to a maximum power factor exceeding 130μW·m^(-1)·K^(-2).These results highlight selenium-driven charge delocalization as a promising approach to modulating charge transport and guide the molecular design of efficient organic thermoelectrics.展开更多
Polymeric carbon nitride(PCN)is identified as a promising photocatalyst for H_(2)O_(2) production due to its visible-light response,low cost,and high selectivity of 2e^(-) oxygen reduction reaction(ORR).However,the H_...Polymeric carbon nitride(PCN)is identified as a promising photocatalyst for H_(2)O_(2) production due to its visible-light response,low cost,and high selectivity of 2e^(-) oxygen reduction reaction(ORR).However,the H_(2)O_(2) yield of carbon nitride is still restricted by narrow light absorption,low charge separation efficiency,and insufficient active sites.Herein,crystalline poly(heptazine imide)(PHI)-based carbon nitride with highly dispersed In sites and N defects was prepared through the ionothermal method using LiCl/KCl as molten salts.The largeπ-conjugated system and the existence of N defects greatly enhance the visible-light harvesting ability.The remaining K^(+) ions in the nitrogen cavities of PHI serve as interlayer electron channels,and the incorporation of N defects triggers asymmetric distribution of charges on the heptazine network,promoting interlayer and in-plane charge separation and transfer,respectively.The In sites accelerate charge transfer dynamics and act as active sites for ORR.The synergistic effect of metal modification and defect engineering boosts the electron delocalization within the photocatalyst and thus significantly improves the photocatalytic activity.The H_(2)O_(2) production rate of 10InPHI reaches 15.3 mmol g^(-1)h^(-1)through a two-step single-electron ORR pathway,underscoring the great potential of modified carbon nitride materials in efficient H_(2)O_(2) photosynthesis.展开更多
Functionalizing ligands on surface metal atoms has been implemented to tune the adsorption behaviors of intermediates in electrochemical CO_(2) reduction reaction(CO_(2)RR).However,it is always bound within an unfavor...Functionalizing ligands on surface metal atoms has been implemented to tune the adsorption behaviors of intermediates in electrochemical CO_(2) reduction reaction(CO_(2)RR).However,it is always bound within an unfavorable linear scaling relationship of the synchronously changed adsorption energies of intermediates.To break it,a win-win diethylamine(DEA)-mediated strategy was proposed to functionalize surface Pd atoms by exchanging the residual oleylamine(OAm) on ultrafine Pd nanoparticles(Pd NPs) with DEA.The molecular dynamics simulations,coupled with in situ Fourier transform infrared spectroscopy results,revealed that DEA hindered less toward CO_(2) than H_(2)O on Pd NPs surface,and induced more CO linear configuration intermediate(^(*)CO_L),indicative of ease CO_(2) transport and CO desorption.Additionally,computational calculations implied that-NH-in DEA delocalized more electrons to surface Pd atoms and formed H-bond with ^(*)COOH,asynchronously changing the adsorption energies of ^(*)COOH and ^(*)CO,which enabled a CO Faraday efficiency(FE_(CO)) close to 100% in an ultrawide potential window and a stability of over 50 h with a FE_(CO) over 90%.This study dexterously addresses the residual issue of end-blocking agents on metal nanostructures from synthesis,and synchronously realizes the surface molecular functionalization,paving a smart avenue to design high-performance electrocatalysts.展开更多
The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improve...The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improvement of HER activity is limited by the unfavorable interaction of hydroxyl generated by the dissociation of water with active sites.Herein,we propose a strategy of alkaline earth metal cations-driven electron delocalization to elaborately tailor the binding of hydroxyl with the active sites.Taking FeNiMg-layered double hydroxides(FeNiMg-LDH)as a prototypical example,the combined operando spectroscopy analysis and theoretical calculations show that the introduction of Mg cations in solid-solution phase can create a local electronic field and delocalize the electron between Fe and adsorbed hydroxyl,resulting in an optimization of hydroxyl binding strength.Accordingly,FeNiMg-LDH lowers the overpotentials to deliver 10 mA cm−2 in alkaline electrolyte by 39 and 64 mV,compared to FeNi-LDH and Ni-LDH catalysts,respectively.This work sheds new light on the rational design of advanced HER electrocatalyst for alkaline water electrolysis.展开更多
The chlorine evolution reaction(CER)serves as the cornerstone and crucial step in the conversion of chloride ions to chlorine gas,while accompanied by the occurrence of the oxygen evolution reaction(OER)in practical p...The chlorine evolution reaction(CER)serves as the cornerstone and crucial step in the conversion of chloride ions to chlorine gas,while accompanied by the occurrence of the oxygen evolution reaction(OER)in practical processes that lead to difficulty in achieving the purity requirements of the product Cl_(2)for industrial applications.Pd-doped Co_(3)O_(4) nanoneedles(Pd-Co_(3)O_(4)NNs)were synthesized via hydrothermal-calcination methods.Pd sites induce electron delocalization,creating asymmetric active Co sites in Co_(3)O_(4),enhancing CER performance.The unique nanoneedle arrays of the designed catalysts increase the number of exposed active sites,facilitating electron transfer and endowing the Pd-Co_(3)O_(4)NNs with a tip catalytic effect,further optimizing the catalytic reaction kinetics of CER with an overpotential of 118 mV at 100 mA cm^(-2)and a Tafel slope of 53.93 mV dec^(-1).The density functional theory(DFT)calculations reveal that Pd incorporation at octahedral sites triggers charge redistribution and d-band center downshift,weakening intermediate adsorption and sustaining catalytic activity.This work offers new insights into noble-metal-doped spinel oxides,highlighting their potential for industrial applications.展开更多
Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish tran...Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish transfer of photogenerated charges.Herein,we report a novel approach involving boron(B)dopinginducedπ-electron delocalization in CN for efficient hydrogen(H2)evolution.The as-prepared B-dopedCN(BCN)catalyst presented an 8.6-fold enhancement in the H2-evolution rate(7924.0μmol h^(−1)g^(−1))under visible-light irradiation compared with pristine CN,which corresponded to an apparent quantum yield(AQY)of 14.5%at 405 nm.Experimental analysis and density functional theory(DFT)calculations demonstrated that B doping inducedπ-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization,thus achieving the high separation and transfer of photoinduced carriers.This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.展开更多
Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique ...Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.展开更多
The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of...The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.展开更多
基金supported by the Guangxi Science and Technology Program(2023AB38061)the National Natural Science Foundation of China(22162004,22479031)the High-performance Computing Platform of Guangxi University。
文摘Co_(3)O_(4) is a promising catalyst for the chlorine evolution reaction(CER)in seawater;however,its CER selectivity is compromised by the adsorption of the competitive oxygen evolution reaction intermediate(OH^(-))at Co sites.Inspired by the hard-soft acid-base(HSAB)theory,this study proposes incorporating early transition metal sites(V)with a low degree of electron delocalization into Co_(3)O_(4) to modulate the selective adsorption of reactants on catalytic sites.Experimental and theoretical calculations reveal that V incorporation facilitates the electron accumulation at the Co site,significantly strengthening the interaction between Co and Cl^(-).Meanwhile,the loss of electrons from V sites generates a more localized electronic state that preferentially adsorbs OH^(-),thus reducing the Co-OH interaction and releasing more Co sites for Cl^(-)adsorption.Therefore,Co_(2)VO_(4) exhibits a high CER selectivity of 92.3%and maintains one of the highest stabilities over 300 h in natural seawater.The resulting half-flow cell achieves~100%disinfection efficiency in seawater,validating the HSAB theory-based design strategy and offering new guidance for developing highly selective seawater CER catalysts.
基金the support from Yunnan Fundamental Research Projects(202301BE070001-029,202401CF070129,202501CF070181)National Natural Science Foundation of China(22209012,22479067)Kunming University of Science and Technology Analysis and Testing Fund Support Project(2023T20220172)。
文摘In order to maximize the advantages of high energy density in Li metal batteries,it is necessary to match cathode materials with high specific capacities.Ni-rich layered oxides have been shown to reversibly embed more Li+during charge and discharge processes due to the increased Ni content in their crystal structure,thereby providing higher energy density.However,a significant challenge associated with Ni-rich layered oxide cathodes is the crossover effect,which arises from the dissolution of Ni^(2+)from the cathode,leading to a rapid decline in battery capacity.Through the delocalization-induced effect of solvent molecules,Ni^(2+)is transformed into a fluorinated transition metal inorganic phase layer,thereby forming a corrosion-resistant Li metal interface.This prevents solvent molecules from being reduced and degraded by Li metal anode.The surface of the Li metal anode exhibits a smooth and flat deposition morphology after long-term cycling.Furthermore,the introduction of Ni^(2+)can enhance the concentration gradient of transition metal ions near the cathode,thereby suppressing the dissolution process of transition metal ions.Even the NCM955 cathode with a mass load of 22 mg cm^(−2)also has great capacity retention after cycling.The Ni^(2+)induced by high electronegative functional groups of solvent under the electron delocalization effect,preventing the Ni ions dissolution of cathode and constructing a corrosion-resistant Li metal interface layer.This work provides new insights into suppressing crossover effects in Li metal batteries with high nickel cathodes.
基金financially supported by the National Natural Science Foundation of China(Nos.51731006,51771093,91860104)the support of the National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology(Grant No.6142909190104)Fundamental Research Funds for the Central Universities(Grant No.30919011295)。
文摘Polysynthetic twinned(PST)TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength,ductility and creep resistance.However,a critical property for high-temperature application of such material involving high-temperature fatigue properties remains unknown.Here,the high-temperature high-cycle fatigue performance of PST TiAl single crystal has been studied.The result shows that PST TiAl single crystal can withstand more than 107 cyclic loadings at 975℃ under a stress amplitude of 270 MPa,which is significantly higher than traditional TiAl alloys.Experimental observations and atomistic simulations indicate that the improvement of fatigue resistance is attributed to the plastic strain delocalization in uniform lamellar structure,and the plastic deformation is well-distributed and sufficient in each lamella.Even in theα2 lamella with difficult slippage,a large number of stacking fault structures can be observed.The{c+a}dislocations inα2 tend to dissociate into a Frank partial with b=1/6<2^(-)20^(-)3>,forming a ribbon of I1 fault which ensures the continuity of deformation.
基金supported by a Grant of the Innovation and Technology Commission of Hong Kong(Project number:ITS/461/18)City University of Hong Kong(Project number:9678179).
文摘Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to design Fe-N-Cs with increased active species content,surface area,and electronic conductivity,their performance is still far from satisfactory.Hitherto,there is limited research about regulation on the electronic spin states of Fe centers for Fe-N-Cs electrocatalysts to improve their catalytic performance.Here,we introduce Ti_(3)C_(2) MXene with sulfur terminals to regulate the electronic configuration of FeN_(4) species and dramatically enhance catalytic activity toward ORR.The MXene with sulfur terminals induce the spin-state transition of FeN_(4) species and Fe 3d electron delocalization with d band center upshift,enabling the Fe(II)ions to bind oxygen in the end-on adsorption mode favorable to initiate the reduction of oxygen and boosting oxygen-containing groups adsorption on FeN_(4) species and ORR kinetics.The resulting FeN_(4)-Ti_(3)C_(2)Sx exhibits comparable catalytic performance to those of commercial Pt-C.The developed wearable ZABs using FeN_(4)-Ti_(3)C_(2)Sx also exhibit fast kinetics and excellent stability.This study confirms that regulation of the electronic structure of active species via coupling with their support can be a major contributor to enhance their catalytic activity.
基金the financial support of this work by the National Natural Science Foundation of China(No.52034011)the Key R&D Program of Shanxi(No.2019ZDLGY04-05)+2 种基金the National Natural Science Foundation of Shaanxi(No.2019JLZ-01)the Fundamental Research Funds for the Central Universities(No.G2020KY05129)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2020-BJ-03)。
文摘Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the strong interactions between the high-polarized bivalent Mg^(2+)ions and anionic lattice.Herein,we design and propose a hetero-structural VO_(2)(R)-VS_(4)cathode,in which the re-delocalized d-electrons can effectively shield the polarity of Mg^(2+)ions.Theoretically,the electrons should spontaneously transfer from VS_(4)to VO_(2)(R)through the interfaces of hetero-structure due to the lower work function value of VS_(4).Furthermore,the internal electrons transfer lead to the electronic injection into VO_(2)(R)from VS_(4)and the partially broken V-V dimers,indicating the presence of lone pair electrons and charge re-delocalization.Benefiting from the shield effect of re-delocalized electrons,and the weakened attraction between cations and O/S anions enables more S^(2-)-S_(2)^(2-)redox groups to participate the electrochemical reactions and compensate the double charge of Mg^(2+)ions.Accordingly,VO_(2)(R)-VS_(4)hetero-structure exhibits a high specific capacity of 554 mA h g^(-1)at 50 mA g^(-1).It is believed that the charge re-delocalization of cathode extremely boost the Mg^(2+)ions migration for the high-capacity of MIBs.
基金Project supported by the State Key Programs for Basic Research of China (Grant Nos. 2005CB623605 and 2006CB921803)the National Natural Science Foundation of China (Grant Nos. 60676056 and 10874071)
文摘We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the localization length is enhanced by disorder of side sites in the case of strong disorder, but in the case of weak disorder there is a plateau in this dependence. The above behaviour is the conjunct influence of the coupling to the surrounding atoms and the antiresonant effect. We also discuss different effects and their physical origin of different types of disorder in such systems. The numerical results show that coupling with the surrounding atoms can induce either the localization or delocalization effect depending on the values of parameters.
基金supported,in part,by the National Science Foundation(DMR-1409396 and CHE-1710408)carried out at the National Center for Electron Microscopy and Molecular Foundry of Lawrence Berkeley National Laboratory,which is supported by the US Department of Energy
文摘Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals （Ir, Pt, and Au） and 4d metals （Ru, Rh, and Pd） were prepared and capped with ethynylphenylacetylene and the impacts of the number of metal d electrons on the nanoparticle optoelectronic properties were examined. Both FTIR and photoluminescence measurements indicate that intraparticle charge delocalization was en- hanced with the increase of the number of d electrons in the same period with palladium being an exception.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFA0702100)the Joint Funds of the National Natural Science Foundation of China+1 种基金the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106)the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)。
文摘The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT)(2022R1F1A1065586,2019R1A6A1A11053838)the GIST Research Institute(GRI)APRI grant funded by the GIST in 2022.
文摘Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.
基金Supported by National Natural Science Foundation of China
文摘Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trifluorostyrenes(Y-TFS's). A series of previously unavailable Y-TFS's were thus obtained.
基金Supported by the National Basic Research Program of China under Grant No 2013CB921804the National Natural Science Foundation of China under Grant Nos 11375060 and 11434011
文摘We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transport dynamics in the two-photon CCA exhibits the entanglement-enhanced two-photon delocalization phenomenon. It is shown that the CCA can realize the localization-to-delocalization transition for two entangled photons.
基金National Natural Science Foundation of China,Grant/Award Numbers:22162009,32360236。
文摘Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer and distribution of photogenerated carriers during the reduction process in this intricate system and deciphering the role of activated groups in promoting reduction efficiency.In this study,we strategically regulate the structure of polymeric carbon nitride to promote the N-doped state,thereby facilitating delocalization electron enrichment.The resulting active sites effectively activate peroxyl disulfate(PDS),generating radicals that expedite the selective reduction of U(VI).This strategic approach mitigates the inherent disadvantage of the short half-life of free radicals in persulfate-based advanced oxidation processes.As a consequence of our endeavors and with the simultaneous presence of PDS and hydrogen peroxide,we achieve an exceptional photoreduction efficiency of 100%within a remarkably short period of 20 min.This breakthrough presents a high-efficiency application with significant potential for addressing the pollution associated with uranylcontaining wastewater.Our findings not only contribute to the fundamental understanding of AOPs but also offer a practical solution with implications for environmental remediation.
基金supported by the Science and Technology Commission of Shanghai Municipality(STCSM)under grant No.23ZR1407400support from Shandong Provincial Natural Science Foundation(ZR2022JQ09)technical assistance with GlWAXS,Zehua Qu for technical assistance with the atomic force microscopy,and Ruihua Gao for technical assistance with UV-vis-NIR spectroscopy.
文摘Achieving high electrical conductivity through doping without compromising the Seebeck coefficient remains a fundamental challenge in organic thermoelectrics,owing to the intrinsic trade-off between the two parameters.Here,we propose a rational molecular design strategy to enhance the charge delocalization by substituting thiophene with selenophene in donor-acceptor(D-A)type of conjugated polymers based on benzo[1,2-b:4,5-b']dithiophene(BDT)and diketone-functionalized benzo[1,2-c:4,5-c']dithiophene(BDD)units.The selenophene substitution,combined with backbone planarization via a phenyl substituent,increases the charge localization length from~7 nm to~11.5 nm.These structural modifications result in a significant improvement of electrical conductivity,from~78 S cm^(-1)to~148 S cm^(-1),while maintaining a high Seebeck coefficient,leading to a maximum power factor exceeding 130μW·m^(-1)·K^(-2).These results highlight selenium-driven charge delocalization as a promising approach to modulating charge transport and guide the molecular design of efficient organic thermoelectrics.
基金supported by the National Natural Science Foundation of China (22278056, 22478058)the Fundamental Research Funds for the Central Universities (DUT22LAB602)the National Key Research and Development Program of China (2022YFA1504402)。
文摘Polymeric carbon nitride(PCN)is identified as a promising photocatalyst for H_(2)O_(2) production due to its visible-light response,low cost,and high selectivity of 2e^(-) oxygen reduction reaction(ORR).However,the H_(2)O_(2) yield of carbon nitride is still restricted by narrow light absorption,low charge separation efficiency,and insufficient active sites.Herein,crystalline poly(heptazine imide)(PHI)-based carbon nitride with highly dispersed In sites and N defects was prepared through the ionothermal method using LiCl/KCl as molten salts.The largeπ-conjugated system and the existence of N defects greatly enhance the visible-light harvesting ability.The remaining K^(+) ions in the nitrogen cavities of PHI serve as interlayer electron channels,and the incorporation of N defects triggers asymmetric distribution of charges on the heptazine network,promoting interlayer and in-plane charge separation and transfer,respectively.The In sites accelerate charge transfer dynamics and act as active sites for ORR.The synergistic effect of metal modification and defect engineering boosts the electron delocalization within the photocatalyst and thus significantly improves the photocatalytic activity.The H_(2)O_(2) production rate of 10InPHI reaches 15.3 mmol g^(-1)h^(-1)through a two-step single-electron ORR pathway,underscoring the great potential of modified carbon nitride materials in efficient H_(2)O_(2) photosynthesis.
基金supported by the Pilot Group Program of the Research Fund for International Senior Scientists (No.22350710789)the Start-up Funding of Central South University (No.206030104)。
文摘Functionalizing ligands on surface metal atoms has been implemented to tune the adsorption behaviors of intermediates in electrochemical CO_(2) reduction reaction(CO_(2)RR).However,it is always bound within an unfavorable linear scaling relationship of the synchronously changed adsorption energies of intermediates.To break it,a win-win diethylamine(DEA)-mediated strategy was proposed to functionalize surface Pd atoms by exchanging the residual oleylamine(OAm) on ultrafine Pd nanoparticles(Pd NPs) with DEA.The molecular dynamics simulations,coupled with in situ Fourier transform infrared spectroscopy results,revealed that DEA hindered less toward CO_(2) than H_(2)O on Pd NPs surface,and induced more CO linear configuration intermediate(^(*)CO_L),indicative of ease CO_(2) transport and CO desorption.Additionally,computational calculations implied that-NH-in DEA delocalized more electrons to surface Pd atoms and formed H-bond with ^(*)COOH,asynchronously changing the adsorption energies of ^(*)COOH and ^(*)CO,which enabled a CO Faraday efficiency(FE_(CO)) close to 100% in an ultrawide potential window and a stability of over 50 h with a FE_(CO) over 90%.This study dexterously addresses the residual issue of end-blocking agents on metal nanostructures from synthesis,and synchronously realizes the surface molecular functionalization,paving a smart avenue to design high-performance electrocatalysts.
基金supported by the National Natural Science Foundation of China(52225104 and 52071084)the Key Research and Development Program of Shanxi Province(2024CY2-GJHX-65)+1 种基金“Shuguang Program”supported by the Shanghai Education Development Foundation and Shanghai Municipal Education Commission(20SG03)Science and Technology Commission of Shanghai Municipality(22520710600)。
文摘The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improvement of HER activity is limited by the unfavorable interaction of hydroxyl generated by the dissociation of water with active sites.Herein,we propose a strategy of alkaline earth metal cations-driven electron delocalization to elaborately tailor the binding of hydroxyl with the active sites.Taking FeNiMg-layered double hydroxides(FeNiMg-LDH)as a prototypical example,the combined operando spectroscopy analysis and theoretical calculations show that the introduction of Mg cations in solid-solution phase can create a local electronic field and delocalize the electron between Fe and adsorbed hydroxyl,resulting in an optimization of hydroxyl binding strength.Accordingly,FeNiMg-LDH lowers the overpotentials to deliver 10 mA cm−2 in alkaline electrolyte by 39 and 64 mV,compared to FeNi-LDH and Ni-LDH catalysts,respectively.This work sheds new light on the rational design of advanced HER electrocatalyst for alkaline water electrolysis.
基金supported by the National Natural Science Foundation of China(Grant Nos.52402273,52272222,52072197)Youth Innovation Team Development Program of Shandong Higher Education Institutions(Grant No.2022KJ155)Taishan Scholar Young Talent Program(Grant No.tsqn201909114)。
文摘The chlorine evolution reaction(CER)serves as the cornerstone and crucial step in the conversion of chloride ions to chlorine gas,while accompanied by the occurrence of the oxygen evolution reaction(OER)in practical processes that lead to difficulty in achieving the purity requirements of the product Cl_(2)for industrial applications.Pd-doped Co_(3)O_(4) nanoneedles(Pd-Co_(3)O_(4)NNs)were synthesized via hydrothermal-calcination methods.Pd sites induce electron delocalization,creating asymmetric active Co sites in Co_(3)O_(4),enhancing CER performance.The unique nanoneedle arrays of the designed catalysts increase the number of exposed active sites,facilitating electron transfer and endowing the Pd-Co_(3)O_(4)NNs with a tip catalytic effect,further optimizing the catalytic reaction kinetics of CER with an overpotential of 118 mV at 100 mA cm^(-2)and a Tafel slope of 53.93 mV dec^(-1).The density functional theory(DFT)calculations reveal that Pd incorporation at octahedral sites triggers charge redistribution and d-band center downshift,weakening intermediate adsorption and sustaining catalytic activity.This work offers new insights into noble-metal-doped spinel oxides,highlighting their potential for industrial applications.
基金the financial support from the National Key Projects for Fundamental Research and Development of China(2021YFA1500803)the National Natural Science Foundation of China(No.22209190)+2 种基金the Central China Normal University(2020CXZZ023)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Beijing Natural Science Foundation(2222081).S.O.appreciates the financial support from the“Guizi Scholar”Program of Central China Normal University and the fellowship of China Postdoctoral Science Foundation(No.GZC20241766,2024M753304).
文摘Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish transfer of photogenerated charges.Herein,we report a novel approach involving boron(B)dopinginducedπ-electron delocalization in CN for efficient hydrogen(H2)evolution.The as-prepared B-dopedCN(BCN)catalyst presented an 8.6-fold enhancement in the H2-evolution rate(7924.0μmol h^(−1)g^(−1))under visible-light irradiation compared with pristine CN,which corresponded to an apparent quantum yield(AQY)of 14.5%at 405 nm.Experimental analysis and density functional theory(DFT)calculations demonstrated that B doping inducedπ-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization,thus achieving the high separation and transfer of photoinduced carriers.This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.
基金supported by the National Nature Science Foundation of China(Nos.52202335 and 52171227)Natural Science Foundation of Jiangsu Province(No.BK20221137)National Key R&D Program of China(2024YFE0108500).
文摘Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.
基金supported by Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012378)Natural Science Foundation of China(Nos.52471093,52274367)+3 种基金fund of the State Key Laboratory of Solidification Processing in NPU(No.2025‐QZ‐03)the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University(No.PF2025041)Fundamental Research Projects of Science&Technology Innovation and development Plan in Yantai City(No.2024JCYJ099)project(No.ZR2024QE213)supported by Shandong Provincial Natural Science Foundation.
文摘The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.
