ZnO-based catalysts have been widely used in hydrogenation reactions,but less attention has been paid to the electrocatalytic hydrogenation process on ZnO electrodes.In this work,the preparation of hydrogen species an...ZnO-based catalysts have been widely used in hydrogenation reactions,but less attention has been paid to the electrocatalytic hydrogenation process on ZnO electrodes.In this work,the preparation of hydrogen species and the associ-ated reduction properties under electrochemi-cal processes in aqueous solutions have been in-vestigated on ZnO and Au/ZnO electrodes.The measurements of cyclic voltammetry(CV),X-ray diffraction,and electron paramagnetic resonance(EPR)confirm the formation of hydro-gen species on the interstitial sites(Hi)or on the oxygen vacancy sites(H_(O)).The hydrogena-tion reaction of p-nitrophenol(pNP)at 40μmol/L occurs on both ZnO and Au/ZnO elec-trodes,and the hydrogenation reduction performance of Au/ZnO electrode is better than that of ZnO electrode.CVs show H_(O)species is much more reactive with pNP than Hi species.Compared with the ZnO electrode,the presence of Au on ZnO promotes the formation of H_(O)species and improves the electro-reduction performance to pNP.These results help us to un-derstand the reaction processes related to the electrochemical hydrogenation on ZnO and Au/ZnO surfaces and shed new light on the design of new catalytic hydrogenation systems.展开更多
Differential electrochemical mass spectrometry(DEMS)is one of the most powerful techniques for both the mechanistic and kinetic study of complicated electrocatalytic reactions.It can provide information on the nature ...Differential electrochemical mass spectrometry(DEMS)is one of the most powerful techniques for both the mechanistic and kinetic study of complicated electrocatalytic reactions.It can provide information on the nature and yields of the products generated,their production rate,and the structure-activity relationship between the electrocatalysts and the target reactions.The precise calibration of the mass signal is a prerequisite for the accurate evaluation of reaction kinetics.In this work,we use the oxidation reactions of CO and HCOOH to demonstrate how certain conditions,such as the flow rate and solution composition,affect the collection efficiency and ionization probability of the species to be detected.These parameters can affect the determination of the mass calibration constant and the accuracy of the subsequent quantitative DEMS analysis.We show the relationship between the mass calibration constant and the flow rate,and provide strategies for eliminating this and the related problems.展开更多
Since the 1980s,single-crystal Pt electrodes with well-defined surface structures have been deemed stable under mild electrochemical conditions(e.g.,in the potential region of electric double layers,underpotential dep...Since the 1980s,single-crystal Pt electrodes with well-defined surface structures have been deemed stable under mild electrochemical conditions(e.g.,in the potential region of electric double layers,underpotential deposition of hydrogen,or mild hydrogen evolution/OH adsorption)and have served as model electrodes for unraveling the structure-performance relation in electrocatalysis.With the advancement of in situ electrochemical microscopy/spectroscopy techniques,subtle surface restructuring under mild electrochemical conditions has been achieved in the last decade.Surface restructuring can considerably modify electrocatalytic properties by generating/destroying highly active sites,thereby interfering with the deduction of the structure-performance relation.In this review,we summarize recent progress in the restructuring of well-defined Pt(-based)electrode surfaces under mild electrochemical conditions.The importance of the meticulous structural characterization of Pt electrodes before,during,and after electrochemical measurements is demonstrated using CO adsorption/oxidation,hydrogen adsorption/evolution,and oxygen reduction as examples.The implications of present findings for correctly identifying the reaction mechanisms and kinetics of other electrocatalytic systems are also briefly discussed.展开更多
Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protec...Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water（H2 O） reduction. Surprisingly, no significant increase of the hydrogen（H2） production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.展开更多
The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is ob...The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is observed,which involves two components,^(3)nπ^(∗) and^(3)ππ^(∗) states.The ^(3)ππ^(∗) component contributes more to the^(3)TX^(∗) when increasing the solvent polarity.The self-quenching rate constant ksq of^(3)TX^(∗)is decreased in the order of CH_(3)CN,CH_(3)CN/CH_(3)OH(1:1),and CH_(3)CN/H_(2)O(1:1),which might be caused by the exciplex formed from hydrogen bond interaction.In the presence of diphenylamine(DPA),the quenching of^(3)TX^(∗)happens efficiently via electron transfer,producing the TX^(⋅−) anion and DPA^(⋅+) cation radicals.Because of insignificant solvent effects on the electron transfer,the electron affinity of the ^(3)nπ^(∗) state is proved to be approximately equal to that of the ^(3)ππ^(∗) state.However,a solvent dependence is found in the dynamic decay of TX^(⋅−) anion radical.In the strongly acid aqueous acetonitrile(pH=3.0),a dynamic equilibrium between protonated and unprotonated TX is definitely observed.Once photolysis,^(3)TXH^(+∗) is produced,which contributes to the new band at 520 nm.展开更多
pH dependent uorescence emission of a thioxanthone-based probe has been re-ported recently.The potential deter-minant factors of pH dependence may provide important clues to design novel thioxanthone-based probes in t...pH dependent uorescence emission of a thioxanthone-based probe has been re-ported recently.The potential deter-minant factors of pH dependence may provide important clues to design novel thioxanthone-based probes in the fu-ture.pH dependence of photochemical kinetics of thioxanthone itself was inves-tigated in this work using nanosecond time-resolved laser ash photolysis.The nanosecond time-resolved transient absorption spectra and kinetics of TX in aqueous acetonitrile were recorded,as well as for a model reaction system including TX with diphenylamine(DPA)as a co-initiator.Besides the well-known absorption peak of ^(3)TX*,other peaks at 417,518,673 and 780 nm,have been reliably attributed to major intermediates in the overall reaction between TX and DPA with photolysis,which has been con rmed to occur along a multistep process.In the strong acidic solution(pH≈3.0),TX and protonated TX ions(TXH^(+))coexist due to protonated equilibrium.Consequently,high proton concentration promotes the predominant decay pathway after photolysis from electron transfer to proton affnity.Subsequently,the di erent primary products,^(3)TXH^(+*)or TX^(·-),proceed di erent secondary reaction channels.In addition,within the wide pH range from weak acid(pH=5.0)to alkaline solution(pH=13.0),the overall reaction mechanism and rates do not show visible changes.展开更多
Researching the dispersion as well as the stability of metals on the oxide surfaces is essentially important for understanding the interaction mecha-nisms at the metal/oxide interfaces and thus optimizing the activiti...Researching the dispersion as well as the stability of metals on the oxide surfaces is essentially important for understanding the interaction mecha-nisms at the metal/oxide interfaces and thus optimizing the activities of the heterogeneous catalysts.Here in this work,we have investigated the growth behavior of Pd particles on the polar surfaces of ZnO with scanning tunneling microscopy(STM).By systematically varying the coverages as well as the annealing temperatures,we found that at room temperature Pd tends to form three-dimensional(3D)round particles on the ZnO(000)surface but grow into monolayer two-dimensional(2D)hexagonal islands on the ZnO(0001)surface.During annealing processes,the Pd particles on ZnO(000)aggregate gently while maintaining the 3D morphology in the mild temperature range but then quickly transform in-to tall hexagonal islands at elevated temperatures.In contrast,the segregation of Pd islands on ZnO(0001)occurs gradually along with the temperature rising without changing the 2D morphology.These results directly reflect the different interaction strengths of Pd on the dis-tinct ZnO polar surfaces.They also provide important input for understanding the facet-de-pendent catalytic mechanisms of the Pd/ZnO catalytic systems.展开更多
Developing greener lignocellulose pretreatment method is one of the important issues in the biomass refining process.This work aims to investigate a recyclable Cu_(2)O/H_(2)O_(2)catalytic pretreatment method for impro...Developing greener lignocellulose pretreatment method is one of the important issues in the biomass refining process.This work aims to investigate a recyclable Cu_(2)O/H_(2)O_(2)catalytic pretreatment method for improving synthesis efficiency of aviation fuel from lignocellulosic biomass.The Cu_(2)O/H_(2)O_(2)catalytic pretreatment dramatically facilitated the preparation of ethanol intermediate and bioaviation fuel.Lignocellulosic biomass pretreated by Cu_(2)O/H_(2)O_(2)showed higher ethanol yield(33.8%).For the synthesis process of aviation fuel,ethanol conversion of 93.1%and aviation fuel selectivity of 70.8%were achieved.On the basis of catalyst characterization,biomass characterization and free radical detection,probable function and mechanism of Cu_(2)O/H_(2)O_(2)catalytic pretreatment were proposed.The cuprous oxide catalyst promoted the formation of hydroxyl radicals,thereby facilitating depolymerization of lignocellulose.Ulteriorly,Cu_(2)O/H_(2)O_(2)catalytic pretreatment enhanced the saccharification of lignocellulosic biomass,which was beneficial for the formation of ethanol intermediate and the production of biofuel.展开更多
Phosphoric acid/phosphate solu-tions are commonly used as buffer solutions in the fundamental stud-ies in electrochemistry.Informa-tion on the nature of adsorbed(bi)phosphate as well as the do-main structures is of gr...Phosphoric acid/phosphate solu-tions are commonly used as buffer solutions in the fundamental stud-ies in electrochemistry.Informa-tion on the nature of adsorbed(bi)phosphate as well as the do-main structures is of great impor-tance in unveiling the impact on electrochemical processes occur-ring at electrode electrolyte interface.In this work,the pH effect on the adsorption of phosphate related species on Pd(111)electrode has been investigated by cyclic voltammetry over a broad pH range from 1 to 14.Af-ter carefully analyzing the related onset desorption potential of(bi)phosphate adsorbate to the thermodynamic equilibrium potential of the corresponding electrode reactions,three dif-ferent phosphate related adsorbates have been identified,which are highly pH-dependent.Our analysis reveals that the dominant phosphate anions in bulk solution undergo deprotona-tion upon adsorption.At pH<1.5,the main adsorbate on Pd(111)is;H_(2)PO_(4)^(λ_(1)^(-))in solutions with 1.5<pH<7,the main adsorbate changes into.HPO_(4)^(λ_2^(-))At higher pHs,PO_(4)^(λ_(3)^(-))on electrode surface dominates.The exact charging value ofλ_(i),which represents the true va-lence of the(bi)phosphate adsorbate,could be determined using theoretical calculations.In addition,our results can not rule out the possibility of co-adsorbed H_(3)PO_(4)molecules on Pd(111)at pH<1.5,which needs to be proved by infrared spectroscopy in the future.展开更多
Nucleotide binding domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3)is an NLR-protein family member that can be activated by diverse exogenous and endogenous stimuli but without direct binding of any of ...Nucleotide binding domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3)is an NLR-protein family member that can be activated by diverse exogenous and endogenous stimuli but without direct binding of any of these pathogen ligands.Biological studies show that inactive NLRP3 is usually in an as-sembly state and its activation requires a kinase protein,NEK7.However,our re-cent computational studies as well as other biological investigations have demonstrated that NEK7 does not play a significant role in the activation of NLRP3 assembly and activation.In-stead,biological studies suggest that NEK7 is essential in the dissociation of inactive NLRP3 assemblies.Despite extensive research,the dissociation mechanism of the inactive NLRP3 as-sembly remains largely elusive.In this work,an improved MM-PBSA method is applied to the protein-protein binding free energies in the inactive NLRP3 decamer.Combined with the po-tential mean force(PMF)computation for the 0°→5°conformational change,the standard free-energy change,ΔG^(0)is calculated for NEK7-driven association of the inactive NLRP3 de-camer.Our calculations show that in the absence of NEK7,the dissociation of the inactive NLRP3 decamer is an energetically unfavorable process(ΔG^(0)=99.69 kcal/mol),whereas upon NEK7 binding,the overall standard free energy differenceΔG^(0)=-24.21 kcal/mol is obtained for the inactive NLRP3 decamer dissociation.The free-energy difference calcula-tions in this work also disclose an energetically optimized dissociation pathway,along which the inactive NLRP3 decamer is disunited by a one-by-one dissociation mechanism.展开更多
Recursively embedded atom neural network(REANN)is a general-purpose atomistic machine learning software package for representing potential energy and other physical properties.The original REANN 1.0 architecture is a ...Recursively embedded atom neural network(REANN)is a general-purpose atomistic machine learning software package for representing potential energy and other physical properties.The original REANN 1.0 architecture is a physically inspired invariant message passing neural network,which was designed for systems with a limited number of elements.It is efficient but hardly transferable to more complex multi-element systems.In this work,we release REANN 2.0 aimed at multi-element systems and universal potentials,which integrates element embedding and equivariant representation.Compared to the first version,REANN 2.0 demonstrates enhanced ele-ment transferability and higher accuracy across various periodic systems with higher efficiency.Built upon this framework,a pre-trained REANN-MPtrj model without fine-tuning accurately predicts the lithium-ion diffusion dynamics in a benchmark solid-state electrolyte Li_(3)YCl_(6).We hope this open-source software package will facilitate the development of computationally efficient universal potentials in the future.展开更多
Strong polyelectrolyte brushes(SPBs)play an important role in enabling material surface functionalization due to their unique stimuli-responsive properties.Although the unexpected pH responsiveness of SPBs has been re...Strong polyelectrolyte brushes(SPBs)play an important role in enabling material surface functionalization due to their unique stimuli-responsive properties.Although the unexpected pH responsiveness of SPBs has been revealed in the past ten years,it is still unclear if the pH-responsive properties of SPBs are affected by the brush thickness.In this study,we employed the positively charged poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride(PMETAC)and negatively charged sodium poly(styrenesulfonate)(NaPSS)brushes as model systems to explore the effect of thickness on the pH-responsive properties of SPBs.The results demonstrate that the pH-responsive properties of SPBs manifest different dependences on the brush thickness.Specifically,for both PMETAC and NaPSS brushes,the pH-responsive hydration and stiffness are influenced by the thickness,and the pH-responsive wettability and adhesion are almost unaffected by the thickness.This work not only provides a clear understanding of the relationship between the brush thickness and the pH responsiveness of SPBs,but also offers a new method to control the pH-responsive properties of SPBs.展开更多
A plasma injection ion source has been de-veloped for the photoelectron velocity imag-ing studies of metal-containing anions.The source employs a pulse discharge nozzle for generating a plasma beam that perpendicu-lar...A plasma injection ion source has been de-veloped for the photoelectron velocity imag-ing studies of metal-containing anions.The source employs a pulse discharge nozzle for generating a plasma beam that perpendicu-larly crosses the master supersonic jet beam from a home-made pulsed piezo valve.The discharge nozzle is designed for high voltage gas discharge with efficient metal sputtering of the cathode,and thus plays a role in met-al atom and ion source.Supersonically jet-cooled anions can be produced in the master gas jet via reactions of the plasma products.The source is integrated into a photoelectron ve-locity imaging spectrometer.Test mass spectrometry experiments show that the ion source can efficiently produce transition metal containing anions,such as FeO_(m)^(-),CuO_(m)^(-),CuC_(n)^(-),CuC_(n)O_(m)^(-).The photoelectron imaging results by photodetachment of O-show that the pho-toelectron energy resolution of the whole instrument isΔE/E≈2.3%,and the results of FeO^(-)indicate that internal temperatures of anions from the source could be efficiently cooled down.展开更多
Ammonia(NH_(3))plays an important role in the world economy and its demand is steadily rising alongside the progress of modern society.The electrocatalytic nitrogen reduction reaction(NRR)is presently regarded as a hi...Ammonia(NH_(3))plays an important role in the world economy and its demand is steadily rising alongside the progress of modern society.The electrocatalytic nitrogen reduction reaction(NRR)is presently regarded as a high-po-tential method for the synthesis of NH_(3).Nev-ertheless,the development of efficient NRR electrocatalysts remains a challenging task.In this study,various transition metal(TM)sin-gle atoms(TM=Sc-Zn,Y-Cd except Tc,and Ta-Pt)anchored onγ-graphyne(γ-GY)are sys-tematically investigated as NRR electrocatalysts using density functional theory(DFT)cal-culations.According to several criteria regarding the adsorption stability of isolated TM sin-gle atoms onγ-graphyne,the adsorption properties of N_(2) on these TM single atoms,the ad-sorption competition between N_(2) and H,and the free energy change in the initial protonation process for N_(2),we find that Os@γ-GY and Re@γ-GY may be suitable electrocatalysts for NRR,and analyze the reasons why the two types of single atoms can well adsorb and activate N_(2) molecules.From the reaction pathways of NRR catalyzed by the two single-atom systems,we further find that NRR is hindered by the step of*NH_(2) hydrogenation to*NH_(3) on Re@γ-GY but can proceed well on Os@γ-GY.Thus,Os@γ-GY behaves best in catalyzing NRR among theγ-GY anchored single atom systems studied.This work has the potential to offer valuable recommendations for the development of novel and highly effective NRR electrocat-alysts.展开更多
A thorough understanding of the growth behaviors of Zn anode at various temperatures is essential for improving the lifespan of Zn-based flow batteries(ZFBs).However,the impact of temperature on Zn deposition in ZFBs ...A thorough understanding of the growth behaviors of Zn anode at various temperatures is essential for improving the lifespan of Zn-based flow batteries(ZFBs).However,the impact of temperature on Zn deposition in ZFBs has not been thoroughly investigated.In this work,we find that at low temperatures(0–40°C)Zn deposit presents a dense and smooth morphology with minimal side reactions,such as hydrogen evolution and aqueous corrosion.Above 60°C,Zn begins to grow vertically on the substrate,forming larger particles and intensifying side reactions.These differences in Zn growth behaviors at varying temperatures are closely linked to changes in Zn nucleation,as observed through in situ atomic force microscopy.Consequently,elevated temperature in a ZFB promotes preferentially vertical deposition of Zn at the membrane/electrode interface,extending into the membrane.As a result,this significantly hinders ion transport across the membrane and substantially increases the risk of short-circuiting.This process is the primary factor contributing to the reduced lifespan of ZFBs at high temperatures.展开更多
It is highly challenging to precisely compare the impacts of anthropogenic pollutants on the photooxidation of isomeric volatile organic compounds with respect to molecular compositions and particle number/mass concen...It is highly challenging to precisely compare the impacts of anthropogenic pollutants on the photooxidation of isomeric volatile organic compounds with respect to molecular compositions and particle number/mass concentrations of secondary organic aerosols(SOAs).In this study,we conducted a series of well-defined indoor chamber experiments to compare the effects of NO_(x)(NO and NO_(2))on the photooxidation of isomeric monoterpenes ofβ-pinene and limonene.For the photooxidation ofβ-pinene with NO_(x),the increase of the initial concentrations of NO([NO]_(0))shows a monotonous suppression of the particle mass concentration,whereas the increase of[NO_(2)]_(0) shows a monotonous enhancement of the particle mass concentration.For the photooxidation of limonene with NO_(x),the increase of[NO]_(0) exhibits a monotonous suppression of the particle mass concentration,whereas the increase of[NO_(2)]_(0) shows a parabolic trend of the particle mass concentration.Utilizing a newly developed vacuum ultraviolet free electron laser(VUV-FEL),the online threshold photoionization mass spectrometry reveals a series of novel compounds at molecular weight(MW)=232 and 306 for theβ-pinene+NO_(x) system and MW=187,261,280,and 306 for the limonene+NO_(x) system.The molecular structures and formation pathways of these species were inferred,which led to the prediction of the diversity and difference of SOA products(i.e.,ester and peroxide accretion products)formed from different monoterpene precursors.To improve the predictions of future air quality,it is recommended that climate models should incorporate the NO_(x)-driven diurnal photooxidation of monoterpenes for SOA formation mechanisms.展开更多
Two-dimensional(2D)heterostructures compris-ing of differently stacking atomic layers are attrac-tive owing to its flexible composition as well as the emerging new physicochemical properties.Howev-er,so far many 2D ve...Two-dimensional(2D)heterostructures compris-ing of differently stacking atomic layers are attrac-tive owing to its flexible composition as well as the emerging new physicochemical properties.Howev-er,so far many 2D vertical heterojunctions are constructed through transfer methods,inevitably introducing interfacial impurities and thus hindering detailed atomic-level studies.In this work,we have developed a clean two-step fabrication strat-egy by combining ultrahigh vacuum(UHV)molecular beam epitaxy(MBE)growth with am-bient chemical vapor deposition(CVD).We first-ly grew single crystalline graphene film on a SiC substrate under UHV condition,and then synthesized MoS_(2)films on the graphene-SiC sur-face through CVD under inert atmosphere,thus successfully realized the construction of a well-defined MoS_(2)-graphene/SiC heterojunction with clean surface.Particularly,we observed the MoS_(2)can not only grow into monolayer flakes but also form spiral structures,the latter showing layer-by-layer stacks with reduced bandgap down to~1.0 eV.展开更多
The catalytic performance of supported metal catalysts is highly dependent on the interfacial contact between the metal centers and support materials,which could dynamically adapt to the chemical environment in the re...The catalytic performance of supported metal catalysts is highly dependent on the interfacial contact between the metal centers and support materials,which could dynamically adapt to the chemical environment in the reactions.Herein,the well-known Ru/TiO_(x)interface of the Ru/TiO_(2)catalyst is shown to be transformed into Ru/TiO_(x)N_(y)during the NH_(3)decomposition,which is derived from the nitridation of the support by N^(*)species.Through a series of characterizations and density functional theory(DFT)calculations,it is found that such a nitrogenous interface primarily blocks the cleavage of N-H bonds with a higher energy barrier,leading to the deactivation of Ru/TiO_(2)in NH_(3)decomposition.Nevertheless,the Ru/TiO_(x)interface can be easily restored by oxidation and a subsequent H2 reduction,contributing to the recovery of the catalytic activity toward NH_(3)decomposition.Our study provides a new insight into the deactivation mechanism of Ru/TiO_(2)in NH_(3)decomposition and highlights the significance of the dynamic evolution of the metal-support interfaces in the reactions.展开更多
In this work,we investigate disordered Dirac fermions from the perspective of quantum entanglement,which provides a different angle compared to the ordinary perturbative renormalization group(RG)analysis.We consider D...In this work,we investigate disordered Dirac fermions from the perspective of quantum entanglement,which provides a different angle compared to the ordinary perturbative renormalization group(RG)analysis.We consider Dirac fermions subjected to random hopping and random flux,which respectively fall into the chiral Gaussian orthogonal ensemble(cGOE)and chiral Gaussian unitary ensemble(cGUE)universality classes.Existing studies based on perturbative calculations suggest that both types of randomness are marginal.Here,through numerical simulations of the corresponding lattice models,we find that these two different types of randomness exhibit distinct entanglement features,signaling completely different properties in contrast to the perturbative RG analysis.In particular,although the entropy area-law is generally held for both types of randomness,we identify that the subleading term of the entanglement entropy is enhanced by random flux but not by random hopping.This subleading term is known as the entropic F-function in the clean limit without disorder.Our observations indicate that disordered theories in cGOE and cGUE are essentially different,which recalls careful analysis on the RG calculations.展开更多
Historically seen as a limitation,grain boundaries(GBs)within polycrystalline metal halide perovskite(MHP)films are thought to impede charge transport,adversely impacting the efficiency of perovskite solar cells(PSCs)...Historically seen as a limitation,grain boundaries(GBs)within polycrystalline metal halide perovskite(MHP)films are thought to impede charge transport,adversely impacting the efficiency of perovskite solar cells(PSCs).In this study,we employ home-built confo-cal photoluminescence microscopy,combined with photocurrent detec-tion modules,to directly visualize the carrier dynamics in the MHP film of PSCs under real operating conditions.Our findings suggest that GBs in high-efficiency PSCs function as carrier transport channels,where a notable enhancement in photocurrent is observed.Femtosecond transient absorption and Kelvin probe force microscopy measurements further validate the existence of a built-in electric field in the vicinity of GBs,offering additional driving force for charge separation and establishing channels for swift carrier transport along the GBs,thereby expediting subsequent charge collection processes.This study elucidates the pivotal role of GBs in operational PSCs and provides valuable insights for the fabrication of high-efficiency PSCs.展开更多
基金supported by the National Key Re-search and Development Program of China(No.2021YFA1500403)the National Natural Science Foundation of China(No.21773047 and No.U1832180)partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.
文摘ZnO-based catalysts have been widely used in hydrogenation reactions,but less attention has been paid to the electrocatalytic hydrogenation process on ZnO electrodes.In this work,the preparation of hydrogen species and the associ-ated reduction properties under electrochemi-cal processes in aqueous solutions have been in-vestigated on ZnO and Au/ZnO electrodes.The measurements of cyclic voltammetry(CV),X-ray diffraction,and electron paramagnetic resonance(EPR)confirm the formation of hydro-gen species on the interstitial sites(Hi)or on the oxygen vacancy sites(H_(O)).The hydrogena-tion reaction of p-nitrophenol(pNP)at 40μmol/L occurs on both ZnO and Au/ZnO elec-trodes,and the hydrogenation reduction performance of Au/ZnO electrode is better than that of ZnO electrode.CVs show H_(O)species is much more reactive with pNP than Hi species.Compared with the ZnO electrode,the presence of Au on ZnO promotes the formation of H_(O)species and improves the electro-reduction performance to pNP.These results help us to un-derstand the reaction processes related to the electrochemical hydrogenation on ZnO and Au/ZnO surfaces and shed new light on the design of new catalytic hydrogenation systems.
基金supported by the National Natural Science Foundation of China(no.21872132,21832004,91545124)the 973 Program from the Ministry of Science and Technology of China(no.2015CB932301)。
文摘Differential electrochemical mass spectrometry(DEMS)is one of the most powerful techniques for both the mechanistic and kinetic study of complicated electrocatalytic reactions.It can provide information on the nature and yields of the products generated,their production rate,and the structure-activity relationship between the electrocatalysts and the target reactions.The precise calibration of the mass signal is a prerequisite for the accurate evaluation of reaction kinetics.In this work,we use the oxidation reactions of CO and HCOOH to demonstrate how certain conditions,such as the flow rate and solution composition,affect the collection efficiency and ionization probability of the species to be detected.These parameters can affect the determination of the mass calibration constant and the accuracy of the subsequent quantitative DEMS analysis.We show the relationship between the mass calibration constant and the flow rate,and provide strategies for eliminating this and the related problems.
文摘Since the 1980s,single-crystal Pt electrodes with well-defined surface structures have been deemed stable under mild electrochemical conditions(e.g.,in the potential region of electric double layers,underpotential deposition of hydrogen,or mild hydrogen evolution/OH adsorption)and have served as model electrodes for unraveling the structure-performance relation in electrocatalysis.With the advancement of in situ electrochemical microscopy/spectroscopy techniques,subtle surface restructuring under mild electrochemical conditions has been achieved in the last decade.Surface restructuring can considerably modify electrocatalytic properties by generating/destroying highly active sites,thereby interfering with the deduction of the structure-performance relation.In this review,we summarize recent progress in the restructuring of well-defined Pt(-based)electrode surfaces under mild electrochemical conditions.The importance of the meticulous structural characterization of Pt electrodes before,during,and after electrochemical measurements is demonstrated using CO adsorption/oxidation,hydrogen adsorption/evolution,and oxygen reduction as examples.The implications of present findings for correctly identifying the reaction mechanisms and kinetics of other electrocatalytic systems are also briefly discussed.
基金supported by the National Science Foundation 9(NSF, No. DMR-1352328)supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, under Contract No. DE-SC0012704
文摘Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water（H2 O） reduction. Surprisingly, no significant increase of the hydrogen（H2） production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.
基金supported by the Educational Commission of Anhui Province of China (No.KJ2018A0491)financial support of Anhui Natural Science Foundation (No.1908085MB50)
文摘The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is observed,which involves two components,^(3)nπ^(∗) and^(3)ππ^(∗) states.The ^(3)ππ^(∗) component contributes more to the^(3)TX^(∗) when increasing the solvent polarity.The self-quenching rate constant ksq of^(3)TX^(∗)is decreased in the order of CH_(3)CN,CH_(3)CN/CH_(3)OH(1:1),and CH_(3)CN/H_(2)O(1:1),which might be caused by the exciplex formed from hydrogen bond interaction.In the presence of diphenylamine(DPA),the quenching of^(3)TX^(∗)happens efficiently via electron transfer,producing the TX^(⋅−) anion and DPA^(⋅+) cation radicals.Because of insignificant solvent effects on the electron transfer,the electron affinity of the ^(3)nπ^(∗) state is proved to be approximately equal to that of the ^(3)ππ^(∗) state.However,a solvent dependence is found in the dynamic decay of TX^(⋅−) anion radical.In the strongly acid aqueous acetonitrile(pH=3.0),a dynamic equilibrium between protonated and unprotonated TX is definitely observed.Once photolysis,^(3)TXH^(+∗) is produced,which contributes to the new band at 520 nm.
基金This work was supported by the Educational Com-mission of Anhui Province of China(No.KJ2018A0491 and KJ2019A0736)the National Natural Science Foun-dation of China(No.21873089)the Natural Science Foundation of Anhui Province(No.1908085MB50).
文摘pH dependent uorescence emission of a thioxanthone-based probe has been re-ported recently.The potential deter-minant factors of pH dependence may provide important clues to design novel thioxanthone-based probes in the fu-ture.pH dependence of photochemical kinetics of thioxanthone itself was inves-tigated in this work using nanosecond time-resolved laser ash photolysis.The nanosecond time-resolved transient absorption spectra and kinetics of TX in aqueous acetonitrile were recorded,as well as for a model reaction system including TX with diphenylamine(DPA)as a co-initiator.Besides the well-known absorption peak of ^(3)TX*,other peaks at 417,518,673 and 780 nm,have been reliably attributed to major intermediates in the overall reaction between TX and DPA with photolysis,which has been con rmed to occur along a multistep process.In the strong acidic solution(pH≈3.0),TX and protonated TX ions(TXH^(+))coexist due to protonated equilibrium.Consequently,high proton concentration promotes the predominant decay pathway after photolysis from electron transfer to proton affnity.Subsequently,the di erent primary products,^(3)TXH^(+*)or TX^(·-),proceed di erent secondary reaction channels.In addition,within the wide pH range from weak acid(pH=5.0)to alkaline solution(pH=13.0),the overall reaction mechanism and rates do not show visible changes.
基金supported by the National Natural Science Foundation of China(No.22172152,No.21872130)the National Key R&D Program of China(No.2021YFA1502801).
文摘Researching the dispersion as well as the stability of metals on the oxide surfaces is essentially important for understanding the interaction mecha-nisms at the metal/oxide interfaces and thus optimizing the activities of the heterogeneous catalysts.Here in this work,we have investigated the growth behavior of Pd particles on the polar surfaces of ZnO with scanning tunneling microscopy(STM).By systematically varying the coverages as well as the annealing temperatures,we found that at room temperature Pd tends to form three-dimensional(3D)round particles on the ZnO(000)surface but grow into monolayer two-dimensional(2D)hexagonal islands on the ZnO(0001)surface.During annealing processes,the Pd particles on ZnO(000)aggregate gently while maintaining the 3D morphology in the mild temperature range but then quickly transform in-to tall hexagonal islands at elevated temperatures.In contrast,the segregation of Pd islands on ZnO(0001)occurs gradually along with the temperature rising without changing the 2D morphology.These results directly reflect the different interaction strengths of Pd on the dis-tinct ZnO polar surfaces.They also provide important input for understanding the facet-de-pendent catalytic mechanisms of the Pd/ZnO catalytic systems.
基金supported by the National Natural Science Foundation of China(No.U21A20288)。
文摘Developing greener lignocellulose pretreatment method is one of the important issues in the biomass refining process.This work aims to investigate a recyclable Cu_(2)O/H_(2)O_(2)catalytic pretreatment method for improving synthesis efficiency of aviation fuel from lignocellulosic biomass.The Cu_(2)O/H_(2)O_(2)catalytic pretreatment dramatically facilitated the preparation of ethanol intermediate and bioaviation fuel.Lignocellulosic biomass pretreated by Cu_(2)O/H_(2)O_(2)showed higher ethanol yield(33.8%).For the synthesis process of aviation fuel,ethanol conversion of 93.1%and aviation fuel selectivity of 70.8%were achieved.On the basis of catalyst characterization,biomass characterization and free radical detection,probable function and mechanism of Cu_(2)O/H_(2)O_(2)catalytic pretreatment were proposed.The cuprous oxide catalyst promoted the formation of hydroxyl radicals,thereby facilitating depolymerization of lignocellulose.Ulteriorly,Cu_(2)O/H_(2)O_(2)catalytic pretreatment enhanced the saccharification of lignocellulosic biomass,which was beneficial for the formation of ethanol intermediate and the production of biofuel.
基金supported by the National Natural Science Foundation of China(No.22172151)。
文摘Phosphoric acid/phosphate solu-tions are commonly used as buffer solutions in the fundamental stud-ies in electrochemistry.Informa-tion on the nature of adsorbed(bi)phosphate as well as the do-main structures is of great impor-tance in unveiling the impact on electrochemical processes occur-ring at electrode electrolyte interface.In this work,the pH effect on the adsorption of phosphate related species on Pd(111)electrode has been investigated by cyclic voltammetry over a broad pH range from 1 to 14.Af-ter carefully analyzing the related onset desorption potential of(bi)phosphate adsorbate to the thermodynamic equilibrium potential of the corresponding electrode reactions,three dif-ferent phosphate related adsorbates have been identified,which are highly pH-dependent.Our analysis reveals that the dominant phosphate anions in bulk solution undergo deprotona-tion upon adsorption.At pH<1.5,the main adsorbate on Pd(111)is;H_(2)PO_(4)^(λ_(1)^(-))in solutions with 1.5<pH<7,the main adsorbate changes into.HPO_(4)^(λ_2^(-))At higher pHs,PO_(4)^(λ_(3)^(-))on electrode surface dominates.The exact charging value ofλ_(i),which represents the true va-lence of the(bi)phosphate adsorbate,could be determined using theoretical calculations.In addition,our results can not rule out the possibility of co-adsorbed H_(3)PO_(4)molecules on Pd(111)at pH<1.5,which needs to be proved by infrared spectroscopy in the future.
基金supported by Ministry of Science and Technology of China(2022YFA1303100)the National Natural Science Foundation of China(No.32090040)。
文摘Nucleotide binding domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3)is an NLR-protein family member that can be activated by diverse exogenous and endogenous stimuli but without direct binding of any of these pathogen ligands.Biological studies show that inactive NLRP3 is usually in an as-sembly state and its activation requires a kinase protein,NEK7.However,our re-cent computational studies as well as other biological investigations have demonstrated that NEK7 does not play a significant role in the activation of NLRP3 assembly and activation.In-stead,biological studies suggest that NEK7 is essential in the dissociation of inactive NLRP3 assemblies.Despite extensive research,the dissociation mechanism of the inactive NLRP3 as-sembly remains largely elusive.In this work,an improved MM-PBSA method is applied to the protein-protein binding free energies in the inactive NLRP3 decamer.Combined with the po-tential mean force(PMF)computation for the 0°→5°conformational change,the standard free-energy change,ΔG^(0)is calculated for NEK7-driven association of the inactive NLRP3 de-camer.Our calculations show that in the absence of NEK7,the dissociation of the inactive NLRP3 decamer is an energetically unfavorable process(ΔG^(0)=99.69 kcal/mol),whereas upon NEK7 binding,the overall standard free energy differenceΔG^(0)=-24.21 kcal/mol is obtained for the inactive NLRP3 decamer dissociation.The free-energy difference calcula-tions in this work also disclose an energetically optimized dissociation pathway,along which the inactive NLRP3 decamer is disunited by a one-by-one dissociation mechanism.
基金the support by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)the National Natural Science Foundation of China(Nos.22325304,22221003 and 22033007)。
文摘Recursively embedded atom neural network(REANN)is a general-purpose atomistic machine learning software package for representing potential energy and other physical properties.The original REANN 1.0 architecture is a physically inspired invariant message passing neural network,which was designed for systems with a limited number of elements.It is efficient but hardly transferable to more complex multi-element systems.In this work,we release REANN 2.0 aimed at multi-element systems and universal potentials,which integrates element embedding and equivariant representation.Compared to the first version,REANN 2.0 demonstrates enhanced ele-ment transferability and higher accuracy across various periodic systems with higher efficiency.Built upon this framework,a pre-trained REANN-MPtrj model without fine-tuning accurately predicts the lithium-ion diffusion dynamics in a benchmark solid-state electrolyte Li_(3)YCl_(6).We hope this open-source software package will facilitate the development of computationally efficient universal potentials in the future.
基金financially supported by the National Natural Science Foundation of China(Nos.22273098,52033001 and 22303032)the Key Project of Anhui Province Science and Technology Innovation Platform(No.S202305a12020030)+1 种基金the Science and Technology Program Project of Zhejiang Province,China(No.2025ZY01057)partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘Strong polyelectrolyte brushes(SPBs)play an important role in enabling material surface functionalization due to their unique stimuli-responsive properties.Although the unexpected pH responsiveness of SPBs has been revealed in the past ten years,it is still unclear if the pH-responsive properties of SPBs are affected by the brush thickness.In this study,we employed the positively charged poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride(PMETAC)and negatively charged sodium poly(styrenesulfonate)(NaPSS)brushes as model systems to explore the effect of thickness on the pH-responsive properties of SPBs.The results demonstrate that the pH-responsive properties of SPBs manifest different dependences on the brush thickness.Specifically,for both PMETAC and NaPSS brushes,the pH-responsive hydration and stiffness are influenced by the thickness,and the pH-responsive wettability and adhesion are almost unaffected by the thickness.This work not only provides a clear understanding of the relationship between the brush thickness and the pH responsiveness of SPBs,but also offers a new method to control the pH-responsive properties of SPBs.
基金supports from the National Natural Science Foundation of China(No.22173089,No.21827804,and No.22103075)the National Key R&D Program of China(No.2021YFA0716801 and No.2017YFA0303502).
文摘A plasma injection ion source has been de-veloped for the photoelectron velocity imag-ing studies of metal-containing anions.The source employs a pulse discharge nozzle for generating a plasma beam that perpendicu-larly crosses the master supersonic jet beam from a home-made pulsed piezo valve.The discharge nozzle is designed for high voltage gas discharge with efficient metal sputtering of the cathode,and thus plays a role in met-al atom and ion source.Supersonically jet-cooled anions can be produced in the master gas jet via reactions of the plasma products.The source is integrated into a photoelectron ve-locity imaging spectrometer.Test mass spectrometry experiments show that the ion source can efficiently produce transition metal containing anions,such as FeO_(m)^(-),CuO_(m)^(-),CuC_(n)^(-),CuC_(n)O_(m)^(-).The photoelectron imaging results by photodetachment of O-show that the pho-toelectron energy resolution of the whole instrument isΔE/E≈2.3%,and the results of FeO^(-)indicate that internal temperatures of anions from the source could be efficiently cooled down.
基金supported by the National Natural Science Foundation of China(No.21825302)the Strate-gic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)USTC-SCC,SCCAS,Tianjin,and Shanghai Supercomputer Centers.
文摘Ammonia(NH_(3))plays an important role in the world economy and its demand is steadily rising alongside the progress of modern society.The electrocatalytic nitrogen reduction reaction(NRR)is presently regarded as a high-po-tential method for the synthesis of NH_(3).Nev-ertheless,the development of efficient NRR electrocatalysts remains a challenging task.In this study,various transition metal(TM)sin-gle atoms(TM=Sc-Zn,Y-Cd except Tc,and Ta-Pt)anchored onγ-graphyne(γ-GY)are sys-tematically investigated as NRR electrocatalysts using density functional theory(DFT)cal-culations.According to several criteria regarding the adsorption stability of isolated TM sin-gle atoms onγ-graphyne,the adsorption properties of N_(2) on these TM single atoms,the ad-sorption competition between N_(2) and H,and the free energy change in the initial protonation process for N_(2),we find that Os@γ-GY and Re@γ-GY may be suitable electrocatalysts for NRR,and analyze the reasons why the two types of single atoms can well adsorb and activate N_(2) molecules.From the reaction pathways of NRR catalyzed by the two single-atom systems,we further find that NRR is hindered by the step of*NH_(2) hydrogenation to*NH_(3) on Re@γ-GY but can proceed well on Os@γ-GY.Thus,Os@γ-GY behaves best in catalyzing NRR among theγ-GY anchored single atom systems studied.This work has the potential to offer valuable recommendations for the development of novel and highly effective NRR electrocat-alysts.
基金financially supported by National Key R&D Program of China (2022YFA1504500)National Natural Science Foundation of China (22372158, 21825203, 22332006, 22288201, 22209179, 22478379 and 22379142)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB0600300)
文摘A thorough understanding of the growth behaviors of Zn anode at various temperatures is essential for improving the lifespan of Zn-based flow batteries(ZFBs).However,the impact of temperature on Zn deposition in ZFBs has not been thoroughly investigated.In this work,we find that at low temperatures(0–40°C)Zn deposit presents a dense and smooth morphology with minimal side reactions,such as hydrogen evolution and aqueous corrosion.Above 60°C,Zn begins to grow vertically on the substrate,forming larger particles and intensifying side reactions.These differences in Zn growth behaviors at varying temperatures are closely linked to changes in Zn nucleation,as observed through in situ atomic force microscopy.Consequently,elevated temperature in a ZFB promotes preferentially vertical deposition of Zn at the membrane/electrode interface,extending into the membrane.As a result,this significantly hinders ion transport across the membrane and substantially increases the risk of short-circuiting.This process is the primary factor contributing to the reduced lifespan of ZFBs at high temperatures.
基金supported by the National Natural Science Foundation of China(Nos.22125303,92361302,92061203,22103082,22273101,22288201,and 21327901)the National Key Research and Development Program of China(No.2021YFA1400501)+3 种基金the Innovation Program for Quantum Science and Technology(No.2021ZD0303304)Dalian Institute of Chemical Physics(No.DICPI202437)Chinese Academy of Sciences(No.GJJSTD20220001)the International Partnership Program of CAS(No.121421KYSB20170012)。
文摘It is highly challenging to precisely compare the impacts of anthropogenic pollutants on the photooxidation of isomeric volatile organic compounds with respect to molecular compositions and particle number/mass concentrations of secondary organic aerosols(SOAs).In this study,we conducted a series of well-defined indoor chamber experiments to compare the effects of NO_(x)(NO and NO_(2))on the photooxidation of isomeric monoterpenes ofβ-pinene and limonene.For the photooxidation ofβ-pinene with NO_(x),the increase of the initial concentrations of NO([NO]_(0))shows a monotonous suppression of the particle mass concentration,whereas the increase of[NO_(2)]_(0) shows a monotonous enhancement of the particle mass concentration.For the photooxidation of limonene with NO_(x),the increase of[NO]_(0) exhibits a monotonous suppression of the particle mass concentration,whereas the increase of[NO_(2)]_(0) shows a parabolic trend of the particle mass concentration.Utilizing a newly developed vacuum ultraviolet free electron laser(VUV-FEL),the online threshold photoionization mass spectrometry reveals a series of novel compounds at molecular weight(MW)=232 and 306 for theβ-pinene+NO_(x) system and MW=187,261,280,and 306 for the limonene+NO_(x) system.The molecular structures and formation pathways of these species were inferred,which led to the prediction of the diversity and difference of SOA products(i.e.,ester and peroxide accretion products)formed from different monoterpene precursors.To improve the predictions of future air quality,it is recommended that climate models should incorporate the NO_(x)-driven diurnal photooxidation of monoterpenes for SOA formation mechanisms.
基金support from the Natural Science Foundation of Jiangsu Province(No.BK20210124)the National Natural Science Foun-dation of China(No.12204512,No.22172152,No.21872130,No.22372193)+3 种基金the National Key Re-search and Development Program of China(No.2021YFA1502801)the joint funds from the Hefei National Synchrotron Radiation Laboratory(No.KY2060000202)We also acknowledge financial support from the CAS Project for Young Scientists in Basic Research(No.YSBR-049)the Fundamental Re-search Funds for the Central Universities(No.WK3510000013,WK2060000066).
文摘Two-dimensional(2D)heterostructures compris-ing of differently stacking atomic layers are attrac-tive owing to its flexible composition as well as the emerging new physicochemical properties.Howev-er,so far many 2D vertical heterojunctions are constructed through transfer methods,inevitably introducing interfacial impurities and thus hindering detailed atomic-level studies.In this work,we have developed a clean two-step fabrication strat-egy by combining ultrahigh vacuum(UHV)molecular beam epitaxy(MBE)growth with am-bient chemical vapor deposition(CVD).We first-ly grew single crystalline graphene film on a SiC substrate under UHV condition,and then synthesized MoS_(2)films on the graphene-SiC sur-face through CVD under inert atmosphere,thus successfully realized the construction of a well-defined MoS_(2)-graphene/SiC heterojunction with clean surface.Particularly,we observed the MoS_(2)can not only grow into monolayer flakes but also form spiral structures,the latter showing layer-by-layer stacks with reduced bandgap down to~1.0 eV.
基金supported by the National Key R&D Program of China(2022YFB4300700)National Natural Science Foundation of China(22008230,22208021,21925803)+6 种基金China Postdoctoral Science Foundation funded project(2020M670807)the Doctoral Scientific Research Foundation of Liaoning Province(2022-BS-014)the Innovation Research Fund Project of Dalian Institute of Chemical Physics(DICP I202224)CAS Specific Research Assistant Funding Programthe fund of the State Key Laboratory of Catalysis in Dalian Institute of Chemical Physics(N-22-08)the Youth Innovation Promotion Association CAS(Y2022061)the Young Topnotch Talents of Liaoning Province(XLYC2203108)。
文摘The catalytic performance of supported metal catalysts is highly dependent on the interfacial contact between the metal centers and support materials,which could dynamically adapt to the chemical environment in the reactions.Herein,the well-known Ru/TiO_(x)interface of the Ru/TiO_(2)catalyst is shown to be transformed into Ru/TiO_(x)N_(y)during the NH_(3)decomposition,which is derived from the nitridation of the support by N^(*)species.Through a series of characterizations and density functional theory(DFT)calculations,it is found that such a nitrogenous interface primarily blocks the cleavage of N-H bonds with a higher energy barrier,leading to the deactivation of Ru/TiO_(2)in NH_(3)decomposition.Nevertheless,the Ru/TiO_(x)interface can be easily restored by oxidation and a subsequent H2 reduction,contributing to the recovery of the catalytic activity toward NH_(3)decomposition.Our study provides a new insight into the deactivation mechanism of Ru/TiO_(2)in NH_(3)decomposition and highlights the significance of the dynamic evolution of the metal-support interfaces in the reactions.
基金supported by the National Key Research and Development Program(Grant No.2022YFA1402204)the National Natural Science Foundation[Grant Nos.22373095(QL),52471020(WC),and 12474144(WZ)]+2 种基金the Innovation Program for Quantum Science and Technology[Grant No.2021ZD0303306(QL)]the Fundamental Research Funds for the Central Universities[Grant No.JZ2025HGQA0310(WC)]the Science Research Foundation for High-Level Talents of Anhui University of Science and Technology[Grant No.YJ20240002(WL)].
文摘In this work,we investigate disordered Dirac fermions from the perspective of quantum entanglement,which provides a different angle compared to the ordinary perturbative renormalization group(RG)analysis.We consider Dirac fermions subjected to random hopping and random flux,which respectively fall into the chiral Gaussian orthogonal ensemble(cGOE)and chiral Gaussian unitary ensemble(cGUE)universality classes.Existing studies based on perturbative calculations suggest that both types of randomness are marginal.Here,through numerical simulations of the corresponding lattice models,we find that these two different types of randomness exhibit distinct entanglement features,signaling completely different properties in contrast to the perturbative RG analysis.In particular,although the entropy area-law is generally held for both types of randomness,we identify that the subleading term of the entanglement entropy is enhanced by random flux but not by random hopping.This subleading term is known as the entropic F-function in the clean limit without disorder.Our observations indicate that disordered theories in cGOE and cGUE are essentially different,which recalls careful analysis on the RG calculations.
基金supported by the CAS Projects for Young Scientists in Basic Research(YSBR-007)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0970302)+4 种基金the National Natural Science Foundation of China(22233005,52272193)the DICP funding(I202315),the Natural Science Foundation of Liaoning(2024JH3/50100010)the LiaoNing Revitalization Talents Program(XLYC2203043)the Dalian Science and Technology Innovation Fund(2024RJ006)the Fundamental Research Funds for the Central Universities(DUT-22LAB602).
文摘Historically seen as a limitation,grain boundaries(GBs)within polycrystalline metal halide perovskite(MHP)films are thought to impede charge transport,adversely impacting the efficiency of perovskite solar cells(PSCs).In this study,we employ home-built confo-cal photoluminescence microscopy,combined with photocurrent detec-tion modules,to directly visualize the carrier dynamics in the MHP film of PSCs under real operating conditions.Our findings suggest that GBs in high-efficiency PSCs function as carrier transport channels,where a notable enhancement in photocurrent is observed.Femtosecond transient absorption and Kelvin probe force microscopy measurements further validate the existence of a built-in electric field in the vicinity of GBs,offering additional driving force for charge separation and establishing channels for swift carrier transport along the GBs,thereby expediting subsequent charge collection processes.This study elucidates the pivotal role of GBs in operational PSCs and provides valuable insights for the fabrication of high-efficiency PSCs.
