Metal halide perovskites(MHPs)with striking electrical and optical properties have appeared at the forefront of semiconductor materials for photocatalytic redox reactions but still suffer from some intrinsic drawbacks...Metal halide perovskites(MHPs)with striking electrical and optical properties have appeared at the forefront of semiconductor materials for photocatalytic redox reactions but still suffer from some intrinsic drawbacks such as inferior stability,severe charge-carrier recombination,and limited active sites.Heterojunctions have recently been widely constructed to improve light absorption,passivate surface for enhanced stability,and promote charge-carrier dynamics of MHPs.However,little attention has been paid to the review of MHPs-based heterojunctions for photocatalytic redox reactions.Here,recent advances of MHPs-based heterojunctions for photocatalytic redox reactions are highlighted.The structure,synthesis,and photophysical properties of MHPs-based heterojunctions are first introduced,including basic principles,categories(such as Schottky junction,type-I,type-II,Z-scheme,and S-scheme junction),and synthesis strategies.MHPs-based heterojunctions for photocatalytic redox reactions are then reviewed in four categories:H2evolution,CO_(2)reduction,pollutant degradation,and organic synthesis.The challenges and prospects in solar-light-driven redox reactions with MHPs-based heterojunctions in the future are finally discussed.展开更多
The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for so...The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for solving environmental and energy issues.In 1972,TiO_(2) was applied for decomposing water into H_(2) and O_(2) via photocatalysis.Owing to its the low visible-light utilization,fast charge recombination,and high energy barrier for water oxidation,overall photocatalytic water-splitting efficiency is extremely low.Because H_(2) is more economically valuable than O_(2),sacrificial agent-assisted photocatalytic H_(2) evolution has been extensively investigated.Because the sacrificial agent can quickly consume photoexcited holes and effectively reduce the water oxidation energy barrier,photocatalytic H_(2) evolution efficiency can be increased by 3-4 orders of magnitude compared to photocatalytic water splitting.However,the overuse of sacrificial agents contributes to wasted photoexcited holes and expensive processes,while presenting potential environmental issues.Recently,overall charge utilization and improved redox efficiency have been achieved by coupling photocatalytic reduction with oxidation reactions.Moreover,overall charge utilization can boost charge separation and increase photocatalyst durability.However,the photocatalytic mechanism of the overall redox reactions remains unclear,owing to the complex reaction processes and design difficulties.Herein,the basic principles of photocatalysis are discussed from the perspective of light harvesting,photoexcited charge separation,thermodynamics,and redox reaction kinetics.Photocatalytic redox reactions,including overall water photodecomposition,photocatalytic H_(2) evolution coupled with organic oxidation,photocatalytic CO_(2) reduction coupled with organic oxidation,photocatalytic H_(2)O_(2) production coupled with organic oxidation,photocatalytic N_(2) reduction coupled with N_(2) oxidation,and photocatalytic organic reduction coupled with organic oxidation,can be systematically classified according to the coupling of photocatalytic oxidation reactions with photocatalytic reduction reactions.Subsequently,the design of photocatalytic redox reactions is considered in terms of the modulation of photocatalyst materials,reaction conditions,and diversity of reactants and products.In addition,the vital role of density functional theory(DFT)calculations for unveiling photoexcited charge transfer,rate-determining steps,and redox reaction barriers are discussed in the context of the work function,electron density difference,Bader charge,and variation in the intermediate adsorption free energy profiles.The activity and mechanism of various photocatalytic redox reactions were elaborately analyzed through in situ characterizations and DFT calculations using representative cases.Finally,the overall photocatalytic redox reactions were summarized with a focus on the construction of an S-scheme heterojunction photocatalyst,reasonable loading of cocatalysts,photocatalyst morphology regulation,novel photocatalyst development,reasonable selection of the oxidation half-reaction and reduction half-reaction for coupling,and combined in situ characterization and DFT calculations.This work provides a reference for promising design strategies and insight into the mechanism of overall photocatalytic redox reactions.展开更多
Preparation of electromagnetic(EM)wave-absorbing composites by interface engineering has been the main strategy to obtain high-performance absorbers.However,the conventional strategy is tedious and time-consuming,whic...Preparation of electromagnetic(EM)wave-absorbing composites by interface engineering has been the main strategy to obtain high-performance absorbers.However,the conventional strategy is tedious and time-consuming,which hinders the scalable synthesis of stable EM wave-absorbing composites.Herein,interface engineering by a redox reaction between transition metal elements in Co-based spinel ferrites was employed to create EM wave-absorbing composites to solve the above problem.Among serial M Co_(2)O_(4)(M=Ni,Cu,and Zn)spinel ferrites,redox reactions during synthesis only occurred between Cu and Co elements,thus leading to the presence of multiple crystal phases on final samples.With the aid of increased polyethylene glycol(PEG)molecular weight(MW),more heterogenous interfaces between CuO and CuCo_(2)O_(4)phases as well as induced crystal defects were generated.Under synergetic interface engineering by means of PEG-assisted redox reaction,interfacial polarization,and defect-induced polarization loss were markedly enhanced on a CuCo_(2)O_(4)-based sample that was prepared with PEG MW of 100 K.The effective absorption bandwidth of the corresponding sample could reach 6.48 GHz(11.52–18 GHz)with a thickness of 2.28 mm.In short,this work provides a novel strategy for designing EM wave absorbing composites by interface engineering through redox reaction instead of the conventional composition coupling process.展开更多
The cleavage and formation of the di sulfide bond of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) were examined in an aqueous solution of pH value from 0 to 14 with and without polyaniline (PAn), The redox reaction of DMcT...The cleavage and formation of the di sulfide bond of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) were examined in an aqueous solution of pH value from 0 to 14 with and without polyaniline (PAn), The redox reaction of DMcT was accelerated by PAn in acidic condition. The cell using this anodic material was set-up and characterized in aqueous electrolyte.展开更多
Tuning the surface properties of catalysts is an effective method for accelerating water electrolysis.Herein,we propose a directional doping and interfacial coupling strategy to design two surface-functionalized Schot...Tuning the surface properties of catalysts is an effective method for accelerating water electrolysis.Herein,we propose a directional doping and interfacial coupling strategy to design two surface-functionalized Schottky junction catalysts for coordinating the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Directional doping with B/S atoms endows amphiphilic g-C_(3)N_(4)with significant n-/p-type semiconductor properties.Further coupling with Fe_(3)C modulates the energy band levels of B-C_(3)N_(4)and S-C_(3)N_(4),thus resulting in functionalized Schottky junction catalysts with specific surface-adsorption properties.The space-charge region generated by the dual modulation induces a local“OH-and Ht-enriched”environment,thus selectively promoting the kinetic behavior of the OER/HER.Impressively,the designed B-C_(3)N_(4)@Fe_(3)C||S-C_(3)N_(4)@Fe_(3)C pair requires only a low voltage of 1.52 V to achieve efficient water electrolysis at 10 mA cm^(-2).This work highlights the potential of functionalized Schottky junction catalysts for coordinating redox reactions in water electrolysis,thereby resolving the trade-off between catalytic activity and stability.展开更多
Fiber-shaped batteries that feature outstanding flexibility,light weight,and wovenability are extremely attractive for powering smart wearable electronic textiles,which further stimulates their demand in extreme envir...Fiber-shaped batteries that feature outstanding flexibility,light weight,and wovenability are extremely attractive for powering smart wearable electronic textiles,which further stimulates their demand in extreme environments.However,there are rare reports on ultralow-temperature fiber batteries to date.This is mainly attributed to the poor conductivity of electrodes and freezing of electrolytes that restrain their satisfactory flexible operation in cold environments.Herein,we propose a fiber cooper metal battery consisting of a conductive polyaniline cathode,an anti-freezing Cu(BF4)2+H3PO4electrolyte and an acidresistant copper wire anode,which can withstand various deformations at ultralow temperatures.Impressively,enhanced capacity and cyclic stability can be achieved by cryoactivated abundant reactive sites in the polyaniline,while benefiting from redox reactions with rapid kinetics involving protons rather than copper ions.Consequently,this well-designed polyaniline/Cu fiber battery delivers excellent flexibility without obvious capacity decay after being bent at-30℃,as well as a remarkable discharge capacity of 120.1 mA h g-1and a capacity retention of 96.8%after 2000 cycles at-50℃.The fiber batteries integrated into wearable textiles can power various electronic devices.These performances greatly outperform those of most reported works.Overall,this work provides a promising strategy toward applications of cryogenic wearable energy storage devices.展开更多
A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plate...A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plateau at ～4.2 V in the initial charge profile, indicating anionic redox reaction(ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ～210 mAh/g, which is probably derived from the participation of both ARR and Mn/Mnredox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mnhelps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.展开更多
Na-ion batteries(NIBs),as one of the next-generation rechargeable battery systems,hold great potential in large-scale energy storage applications owing to the abundance and costeffectiveness of sodium resources.Despit...Na-ion batteries(NIBs),as one of the next-generation rechargeable battery systems,hold great potential in large-scale energy storage applications owing to the abundance and costeffectiveness of sodium resources.Despite the extensive exploration of electrode materials,the relatively low attainable capacity of NIBs hinders their practical application.In recent years,the anionic redox reaction(ARR)in NIBs has been emerging as a new paradigm to deliver extra capacity and thus offers an opportunity to break through the intrinsic energy density limit.In this review,the fundamental investigation of the ARR mechanism and the latest exploration of cathode materials are summarized,in order to highlight the significance of reversible anionic redox and suggest prospective developing directions.展开更多
The pre-edges of oxygen-K X-ray absorption spectra have been ubiquitous in transition metal(TM)oxide studies in various fields,especially on the fervent topic of oxygen redox states in battery electrodes.However,criti...The pre-edges of oxygen-K X-ray absorption spectra have been ubiquitous in transition metal(TM)oxide studies in various fields,especially on the fervent topic of oxygen redox states in battery electrodes.However,critical debates remain on the use of the O-K pre-edge variations upon electrochemical cycling as evidences of oxygen redox reactions,which has been a popular practice in the battery field.This study presents an investigation of the O-K pre-edge of 55 oxides covering all 3d TMs with different elements,structures,and electrochemical states through combined experimental and theoretical analyses.It is shown unambiguously that the O-K pre-edge variation in battery cathodes is dominated by changing TM-d states.Furthermore,the pre-edge enables a unique opportunity to project the lowest unoccupied TM-d states onto one common energy window,leading to a summary map of the relative energy positions of the low-lying TM states,with higher TM oxidation states at lower energies,corresponding to higher electrochemical potentials.The results naturally clarify some unusual redox reactions,such as Cr^(3+/6+).This work provides a critical clarification on O-K pre-edge interpretation and more importantly a benchmark database of O-K pre-edge for characterizing redox reactions in batteries and other energy materials.展开更多
The redox reaction of gold III chloride in acid solutions has been electro-chemically investigated using a cyclic voltammetry technique. This paper emphasizes the current and potential sites at which gold III chloride...The redox reaction of gold III chloride in acid solutions has been electro-chemically investigated using a cyclic voltammetry technique. This paper emphasizes the current and potential sites at which gold III chloride is reduced in hydrochloric acid that is vital to electrochemical evaluation of gold recovery. The solutions were prepared by reacting HCl with AuCl3 in various concentrations thus 30 and 60 mg/L AuCl3 in 0.1 and 0.5 M HCl, respectively. Solutions of 0.1 and 0.5 M HCl containing 0, 30 and 60 mg/L AuCl3, respectively were tested for possible reduction and oxidation reactions by cyclic voltammogram experiment using a glassy carbon, a saturated calomel and a platinum wire mesh as working, reference and counter electrodes, respectively. The results showed no peak in the case of the absence of AuCl3 in the solutions, but appreciable cathodic and anodic peaks for the reduction and oxidation of various concentrations of AuCl3 in acid solutions. The reaction between AuCl3 and HCl was found to be reversible because the ratio of oxidation peak current and reduction peak current was 1. The concentration of AuCl-4 on the surface of the working electrode at the reduction site for each AuCl3 concentration using Nernst equation was 1.22 × 109 ppm and 2.44 × 109 ppm. The reduction potentials were independent of concentration, while the current was highly dependent of concentration.展开更多
Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batt...Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batteries because of their ultrahigh specific capacity. However, redox reaction mechanisms, especially for the anionic redox reaction of these materials, are still not very clear. Meanwhile, several pivotal challenges associated with the redox reactions mechanisms, such as structural instability and limited cycle life, hinder the practical applications of these high-capacity lithium-rich cathode oxides. Herein, we review the lithium-rich oxides with various crystal structures. The multivalent cationic/anionic redox reaction mechanisms of several representative high capacity lithium-rich cathode oxides are discussed, attempting to understand the origins of the high lithium storage capacities of these materials. In addition, we provide perspectives for the further development of these lithium-rich cathode oxides based on multivalent cationic and anionic redox reactions, focusing on addressing the fundamental problems and promoting their practical applications.展开更多
Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed noble-metal nanoparticles （Au, Pd, Pt...Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed noble-metal nanoparticles （Au, Pd, Pt） were immobilized on MIL-100（Fe） （denoted M@MIL-100（Fe）） using a facile room-temperature photodeposition technique. The resulting M@MIL-100（Fe） （M = Au, Pd, and Pt） nanocomposites exhibited enhanced photoactivities toward photocatalytic degradation of methyl orange （MO） and reduction of heavy-metal Cr（VI） ions under visible-light irradiation （A ≥ 420 nm） compared with blank-MIL-100（Fe）. Combining these results with photoelectrochemical analyses revealed that noble-metal deposition can effectively improve the charge-separation efficiency of MIL-100（Fe） under visible-light irradiation. This phenomenon in turn leads to the enhancement of visible-light-driven photoactivity of M@MIL-100（Fe） toward photocatalytic redox reactions. In particular, the Pt@MIL-100（Fe） with an average Pt particle size of 2 nm exhibited remarkably enhanced photoactivities compared with those of M@MIL-100（Fe） （M = Au and Pd）, which can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of the photogenerated charge carrier. In addition, possible photocatalytic reaction mechanisms are also proposed.展开更多
As one of the high-capacity anodes in lithium-ion batteries(LIBs),silicon oxide(SiOx)has attracted wide attention due to its high theoretical capacity,low cost,and proper working voltage.However,the huge volume change...As one of the high-capacity anodes in lithium-ion batteries(LIBs),silicon oxide(SiOx)has attracted wide attention due to its high theoretical capacity,low cost,and proper working voltage.However,the huge volume change and the intrinsic poor conductivity of SiOx still hinder the practical applications.How to address the issues is the focus of current research.In this work,firstly,hydrogen passivated Si nanosheets(Si6H6)were prepared from Zintl phase CaSi2,then,two-dimensional Ag nanoparticle modified SiOVC nanocomposite was prepared via a facile complex redox reaction between SieH6 and AgN03-aniline complexing agent.In this design,aniline was served as carbon sources,and Si6H6could be transformed to SiOx by AgN03 in mild solution condition.The obtained Ag modified SiOVC(SiOx/C-Ag)electrode exhibited high specific capacity(550 mAh·g^(-1)at 0.6 A·g^(-1)),superior rate,and cycling performance when served as anode for LIBs.展开更多
The anionic redox reaction(ARR)is a promising charge contributor to improve the reversible capacity of layeredoxide cathodes for Na-ion batteries;however,some practical bottlenecks still need to be eliminated,includin...The anionic redox reaction(ARR)is a promising charge contributor to improve the reversible capacity of layeredoxide cathodes for Na-ion batteries;however,some practical bottlenecks still need to be eliminated,including a low capacity retention,large voltage hysteresis,and low rate capability.Herein,we proposed a high-Na content honeycomb-ordered cathode,P2–Na_(5/6)[Li_(1/6)Cu_(1/6)Mn_(2/3)]O_(2)(P2-NLCMO),with combined cationic/anionic redox.Neutron powder diffraction and X-ray diffraction of P2-NLCMO suggested P2-type stacking with rarely found P6322 symmetry.In addition,advanced spectroscopy techniques and density functional theory calculations confirmed the synergistic stabilizing relationship between the Li/Cu dual honeycomb centers,achieving fully active Cu^(3+)/Cu^(2+) redox and stabilized ARR with interactively suppressed local distortion.With a meticulously regulated charge/discharge protocol,both the cycling and rate capability of P2-NLCMO were significantly.展开更多
The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries.However,the activation of anionic redox reaction...The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries.However,the activation of anionic redox reaction in layered oxides has significant voltage hysteresis and decay that reduce battery performance and limit commercialization.Here,we critically review the up-todate development of anionic redox reaction in layered oxide cathodes,summarize the proposed reaction mechanism,and unveil their connection to voltage hysteresis and decay based on the state-of-the-art progress.In addition,advances associated with various modification approaches to mitigate the voltage hysteresis/decay in layered transition metal oxide cathodes are also included.Finally,we conclude with an appraisal of further research directions including rational design of high-performance layered oxide cathodes with reversible anionic redox reactions and suppressed voltage hysteresis/decay.Findings will be of immediate benefit to the development of layered oxide cathodes for high performance rechargeable batteries.展开更多
Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chem...Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chemical properties,resulting from irreversible oxygen redox reactions and phase transition processes at high voltages,and thus hinder their large-scale application.This work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_(0.7)5Li_(0.25-2/3x)CuxMn_(0.75-1/3x)O_(2)via Cu doping.Ex-situ XPS demonstrates that Cu doping reduces the amount of Mn^(3+)that triggers the Jahn-Teller effect during the cycling.In addition,the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen,and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between O-O.Meanwhile,in-situ XRD results verify that the Na_(0.7)5Li_(0.19)Cu_(0.09)Mn_(0.7)2O_(2)maintains the P2 phase structure during charging and discharging,resulting in a near-zero strain characteristic of 1.9%.Therefore,the optimized cathode delivers a high reversible capacity of 194.9 mAh g−1 at 0.1 C and excellent capacity retention of 88.6%after 100 cycles at 5 C.The full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg−1.Our research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.展开更多
Sulfur redox reactions render lithium–sulfur(Li–S)batteries with an energy density of>500Whkg−1 but suffer a low practical capacity and fast capacity fade due to sluggish sulfur redox reaction(SRR)kinetics,which ...Sulfur redox reactions render lithium–sulfur(Li–S)batteries with an energy density of>500Whkg−1 but suffer a low practical capacity and fast capacity fade due to sluggish sulfur redox reaction(SRR)kinetics,which lies in the complex reaction process that involves a series of reaction intermediates and proceeds via a cascade reaction.Here,we present a Pt–Cu dual-atom catalyst(Pt/Cu-NG)as an electrocatalyst for sulfur redox reactions.Pt/Cu-NG enabled the rapid conversion of soluble polysulfide intermediates into insoluble Li2S2/Li2S,and consequently,it prevented the accumulation and shuttling of lithium polysulfides,thus outperforming the corresponding single-atom catalysts(SACs)with individual Pt or Cu sites.Operando X-ray absorption spectroscopy and density functional theory calculations revealed that a synergistic effect between the paired Pt and Cu atoms modifies the electronic structure of the Pt site through d-orbital interactions,resulting in an optimal moderate interaction of the metal atom with the different sulfide species.This optimal interaction enhanced charge transfer kinetics and promoted sulfur redox reactions.Our work thus provides important insights on the atomic scale into the synergistic effects operative in dual-atom catalysts and will thus pave the way to electrocatalysts with enhanced efficiency for high-performance Li–S batteries.展开更多
Great efforts have been made in investigating the neurotoxicity of dopamine(DA)in the presence of manganous ions.In contrast,here,we probe the possibility of DA-based cancer chemotherapy by leveraging intratumoral red...Great efforts have been made in investigating the neurotoxicity of dopamine(DA)in the presence of manganous ions.In contrast,here,we probe the possibility of DA-based cancer chemotherapy by leveraging intratumoral redox reactions of DA for producing cytotoxic species in situ.For this purpose,we have constructed a Mn-engineered,DA-loaded nanomedicine.Based on the unique size effect of the nanocarrier,this nanomedicine will not enter the central nervous system but can effectively accumulate in the tumor region,after which the nanocarrier can degrade to release Mn^(2+)and DA in response to the mild acidic intracelluar microenvironment of cancer cells.DA can chelate Mn^(2+)to form a binary coordination complex,where the strong metal-ligand interaction significantly promotes electron delocalization and elevates the reducibility of Mn center,favoring two sequential one-electron oxygen reduction reactions forming H_(2)O_(2),which can be further converted into highly oxidizing ·OH under the cocatalysis by Mn^(2+)and intracellular Fe^(2+).Additionally,as a twoelectron oxidation product of DA ligand,DA-oquinone is potent in exhausting cellular sulfhydryl and depleting reduced glutathione,inhibiting the intrinsic antioxidative mechanism of cancer cells,finally triggering severe oxidative damages in a synergistic manner.It is expected that such a strategy of nanotechnology-mediated metal-ligand coordination and subsequent nontoxicity-to-toxicity transition of DA in tumor may provide a promising prospect for future chemotherapy design.展开更多
Subject Code:H30 With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Hu Youcai(胡友财),Prof.Yu Shishan(庾石山)and Prof.Tang Yi(唐奕)from the St...Subject Code:H30 With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Hu Youcai(胡友财),Prof.Yu Shishan(庾石山)and Prof.Tang Yi(唐奕)from the State Key Laboratory of Bioactive Substance and Function of Natural Medicines,Institute展开更多
CONSPECTUS:Lithium−sulfur(Li-S)batteries have emerged as a promising energy storage technology driven by their potential to reach very high theoretical specific energy densities of up to 2600 Wh·kg^(−1).This rema...CONSPECTUS:Lithium−sulfur(Li-S)batteries have emerged as a promising energy storage technology driven by their potential to reach very high theoretical specific energy densities of up to 2600 Wh·kg^(−1).This remarkably high energy density directly results from the reversible,multi-electron-transfer reactions between sulfur and lithium metal taking place during the charge and discharge cycles.However,the charge/discharge processes of Li-S batteries are invariably accompanied by changes in both the composition and the structure of the sulfur species in the cathode,all of which result in sluggish and incomplete sulfur transformation.It has been demonstrated that the application of electrocatalysts is an effective strategy to accelerate the sulfur reduction reaction(SRR).Recognizing this challenge,researchers worldwide have tried to develop efficient catalysts to accelerate the kinetics of the SRR and boost the overall performance of Li-S batteries.However,this goal necessitates an in-depth understanding of the intricate catalytic processes in the Li-S battery cathode.The effective characterization of the catalysts and a thorough investigation of the SRR process are essential steps to unraveling the underlying catalytic mechanism of sulfur reduction and to compare the performances of the different electrocatalysts.Nonetheless,this pursuit is hindered by the inherent complexity of the SRR process,which remains uniquely specific to the Li-S system under study.Throughout the SRR process,a multitude of intermediate products are created through catalytic conversions between liquid−solid and solid−solid phases.This complexity is markedly different from established heterogeneous catalytic processes,such as water-splitting reactions,where reactants,products,and reaction phases are relatively simple.Given these challenges,our response has been to design a series of catalysts with controlled structures to gain an in-depth understanding of the intricate reaction processes within Li-S catalysis.In this Account,we have undertaken a comprehensive analysis of the structure−function relationships governing the active sites of electrocatalysts in SRR.Our work thus encompasses three aspects-catalytic sites:their geometry and evolution during the reaction,catalytic mechanisms:a key factor that determines SRR kinetics,and catalytic materials:intelligent design toward optimized performance.Also presented in this Account is a brief discussion covering the broader domain of other electrocatalysts and sulfurbased electrochemical systems.Drawing upon the insights obtained from these works,we present future perspectives on potential opportunities and hurdles in the wider application of sulfur cathode electrocatalysts.展开更多
基金financially supported by National Natural Science Foundation of China(No.22302155)the Fundamental Research Funds of the Center Universities(No.D5000240188)the research program of ZJUT(YJY-ZS-20240001)。
文摘Metal halide perovskites(MHPs)with striking electrical and optical properties have appeared at the forefront of semiconductor materials for photocatalytic redox reactions but still suffer from some intrinsic drawbacks such as inferior stability,severe charge-carrier recombination,and limited active sites.Heterojunctions have recently been widely constructed to improve light absorption,passivate surface for enhanced stability,and promote charge-carrier dynamics of MHPs.However,little attention has been paid to the review of MHPs-based heterojunctions for photocatalytic redox reactions.Here,recent advances of MHPs-based heterojunctions for photocatalytic redox reactions are highlighted.The structure,synthesis,and photophysical properties of MHPs-based heterojunctions are first introduced,including basic principles,categories(such as Schottky junction,type-I,type-II,Z-scheme,and S-scheme junction),and synthesis strategies.MHPs-based heterojunctions for photocatalytic redox reactions are then reviewed in four categories:H2evolution,CO_(2)reduction,pollutant degradation,and organic synthesis.The challenges and prospects in solar-light-driven redox reactions with MHPs-based heterojunctions in the future are finally discussed.
文摘The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for solving environmental and energy issues.In 1972,TiO_(2) was applied for decomposing water into H_(2) and O_(2) via photocatalysis.Owing to its the low visible-light utilization,fast charge recombination,and high energy barrier for water oxidation,overall photocatalytic water-splitting efficiency is extremely low.Because H_(2) is more economically valuable than O_(2),sacrificial agent-assisted photocatalytic H_(2) evolution has been extensively investigated.Because the sacrificial agent can quickly consume photoexcited holes and effectively reduce the water oxidation energy barrier,photocatalytic H_(2) evolution efficiency can be increased by 3-4 orders of magnitude compared to photocatalytic water splitting.However,the overuse of sacrificial agents contributes to wasted photoexcited holes and expensive processes,while presenting potential environmental issues.Recently,overall charge utilization and improved redox efficiency have been achieved by coupling photocatalytic reduction with oxidation reactions.Moreover,overall charge utilization can boost charge separation and increase photocatalyst durability.However,the photocatalytic mechanism of the overall redox reactions remains unclear,owing to the complex reaction processes and design difficulties.Herein,the basic principles of photocatalysis are discussed from the perspective of light harvesting,photoexcited charge separation,thermodynamics,and redox reaction kinetics.Photocatalytic redox reactions,including overall water photodecomposition,photocatalytic H_(2) evolution coupled with organic oxidation,photocatalytic CO_(2) reduction coupled with organic oxidation,photocatalytic H_(2)O_(2) production coupled with organic oxidation,photocatalytic N_(2) reduction coupled with N_(2) oxidation,and photocatalytic organic reduction coupled with organic oxidation,can be systematically classified according to the coupling of photocatalytic oxidation reactions with photocatalytic reduction reactions.Subsequently,the design of photocatalytic redox reactions is considered in terms of the modulation of photocatalyst materials,reaction conditions,and diversity of reactants and products.In addition,the vital role of density functional theory(DFT)calculations for unveiling photoexcited charge transfer,rate-determining steps,and redox reaction barriers are discussed in the context of the work function,electron density difference,Bader charge,and variation in the intermediate adsorption free energy profiles.The activity and mechanism of various photocatalytic redox reactions were elaborately analyzed through in situ characterizations and DFT calculations using representative cases.Finally,the overall photocatalytic redox reactions were summarized with a focus on the construction of an S-scheme heterojunction photocatalyst,reasonable loading of cocatalysts,photocatalyst morphology regulation,novel photocatalyst development,reasonable selection of the oxidation half-reaction and reduction half-reaction for coupling,and combined in situ characterization and DFT calculations.This work provides a reference for promising design strategies and insight into the mechanism of overall photocatalytic redox reactions.
基金supported by the National Natural Science Foundation of China(No.22372074)the Yunnan Fundamental Research Projects(No.202101AV070008)+2 种基金the Major Basic Research Project of Science and Technology of Yunnan(No.202302AG050007)Yunnan Innovation Team of Graphene Mechanism Research and Application Industrialization(No.202305AS350017)Graphene Application and Engineering Research Center of Education Department of Yunnan Providence(No.KKPP202351001).
文摘Preparation of electromagnetic(EM)wave-absorbing composites by interface engineering has been the main strategy to obtain high-performance absorbers.However,the conventional strategy is tedious and time-consuming,which hinders the scalable synthesis of stable EM wave-absorbing composites.Herein,interface engineering by a redox reaction between transition metal elements in Co-based spinel ferrites was employed to create EM wave-absorbing composites to solve the above problem.Among serial M Co_(2)O_(4)(M=Ni,Cu,and Zn)spinel ferrites,redox reactions during synthesis only occurred between Cu and Co elements,thus leading to the presence of multiple crystal phases on final samples.With the aid of increased polyethylene glycol(PEG)molecular weight(MW),more heterogenous interfaces between CuO and CuCo_(2)O_(4)phases as well as induced crystal defects were generated.Under synergetic interface engineering by means of PEG-assisted redox reaction,interfacial polarization,and defect-induced polarization loss were markedly enhanced on a CuCo_(2)O_(4)-based sample that was prepared with PEG MW of 100 K.The effective absorption bandwidth of the corresponding sample could reach 6.48 GHz(11.52–18 GHz)with a thickness of 2.28 mm.In short,this work provides a novel strategy for designing EM wave absorbing composites by interface engineering through redox reaction instead of the conventional composition coupling process.
文摘The cleavage and formation of the di sulfide bond of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) were examined in an aqueous solution of pH value from 0 to 14 with and without polyaniline (PAn), The redox reaction of DMcT was accelerated by PAn in acidic condition. The cell using this anodic material was set-up and characterized in aqueous electrolyte.
基金supported by the National Natural Science Foundation of China(No.51672208)the Key Science and Technology Innovation Team of Shaanxi Province(2022TD-34)Open foundation Project of Key Laboratory of Plateau Green Building and Ecological Community of Qinghai Province(KLKF-2019-002)。
文摘Tuning the surface properties of catalysts is an effective method for accelerating water electrolysis.Herein,we propose a directional doping and interfacial coupling strategy to design two surface-functionalized Schottky junction catalysts for coordinating the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Directional doping with B/S atoms endows amphiphilic g-C_(3)N_(4)with significant n-/p-type semiconductor properties.Further coupling with Fe_(3)C modulates the energy band levels of B-C_(3)N_(4)and S-C_(3)N_(4),thus resulting in functionalized Schottky junction catalysts with specific surface-adsorption properties.The space-charge region generated by the dual modulation induces a local“OH-and Ht-enriched”environment,thus selectively promoting the kinetic behavior of the OER/HER.Impressively,the designed B-C_(3)N_(4)@Fe_(3)C||S-C_(3)N_(4)@Fe_(3)C pair requires only a low voltage of 1.52 V to achieve efficient water electrolysis at 10 mA cm^(-2).This work highlights the potential of functionalized Schottky junction catalysts for coordinating redox reactions in water electrolysis,thereby resolving the trade-off between catalytic activity and stability.
基金the financial support from the National Natural Science Foundation of China(52273171 and 21875055)the Shenzhen Research Foundation Project(GXWD20201230155427003)。
文摘Fiber-shaped batteries that feature outstanding flexibility,light weight,and wovenability are extremely attractive for powering smart wearable electronic textiles,which further stimulates their demand in extreme environments.However,there are rare reports on ultralow-temperature fiber batteries to date.This is mainly attributed to the poor conductivity of electrodes and freezing of electrolytes that restrain their satisfactory flexible operation in cold environments.Herein,we propose a fiber cooper metal battery consisting of a conductive polyaniline cathode,an anti-freezing Cu(BF4)2+H3PO4electrolyte and an acidresistant copper wire anode,which can withstand various deformations at ultralow temperatures.Impressively,enhanced capacity and cyclic stability can be achieved by cryoactivated abundant reactive sites in the polyaniline,while benefiting from redox reactions with rapid kinetics involving protons rather than copper ions.Consequently,this well-designed polyaniline/Cu fiber battery delivers excellent flexibility without obvious capacity decay after being bent at-30℃,as well as a remarkable discharge capacity of 120.1 mA h g-1and a capacity retention of 96.8%after 2000 cycles at-50℃.The fiber batteries integrated into wearable textiles can power various electronic devices.These performances greatly outperform those of most reported works.Overall,this work provides a promising strategy toward applications of cryogenic wearable energy storage devices.
基金supported by funding from Science and Technology Project of the State Grid Corporation of China("research on key technology of low-strain layered oxides for long-life Na-ion batteries",No.DG71-16-027)
文摘A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plateau at ～4.2 V in the initial charge profile, indicating anionic redox reaction(ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ～210 mAh/g, which is probably derived from the participation of both ARR and Mn/Mnredox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mnhelps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51725206 and 52002394)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21070500).
文摘Na-ion batteries(NIBs),as one of the next-generation rechargeable battery systems,hold great potential in large-scale energy storage applications owing to the abundance and costeffectiveness of sodium resources.Despite the extensive exploration of electrode materials,the relatively low attainable capacity of NIBs hinders their practical application.In recent years,the anionic redox reaction(ARR)in NIBs has been emerging as a new paradigm to deliver extra capacity and thus offers an opportunity to break through the intrinsic energy density limit.In this review,the fundamental investigation of the ARR mechanism and the latest exploration of cathode materials are summarized,in order to highlight the significance of reversible anionic redox and suggest prospective developing directions.
基金supported by the LDRD program at the LBNL and facilitated by a User Program at The Molecular Foundry(TMF)provided by the TMF clusters(managed by the High Performance Computing Services Group,at LBNL)+3 种基金by the National Energy Research Scientific Computing Center(NERSC)supported by the Office of Science of the US DOE under Contract No.DE-AC02-05CH11231support from EERE VTO under the Applied Battery Materials Program of the US DOE with Contract No.DE-AC02-05CH11231supported by the DOE VTO at Argonne National Laboratory
文摘The pre-edges of oxygen-K X-ray absorption spectra have been ubiquitous in transition metal(TM)oxide studies in various fields,especially on the fervent topic of oxygen redox states in battery electrodes.However,critical debates remain on the use of the O-K pre-edge variations upon electrochemical cycling as evidences of oxygen redox reactions,which has been a popular practice in the battery field.This study presents an investigation of the O-K pre-edge of 55 oxides covering all 3d TMs with different elements,structures,and electrochemical states through combined experimental and theoretical analyses.It is shown unambiguously that the O-K pre-edge variation in battery cathodes is dominated by changing TM-d states.Furthermore,the pre-edge enables a unique opportunity to project the lowest unoccupied TM-d states onto one common energy window,leading to a summary map of the relative energy positions of the low-lying TM states,with higher TM oxidation states at lower energies,corresponding to higher electrochemical potentials.The results naturally clarify some unusual redox reactions,such as Cr^(3+/6+).This work provides a critical clarification on O-K pre-edge interpretation and more importantly a benchmark database of O-K pre-edge for characterizing redox reactions in batteries and other energy materials.
文摘The redox reaction of gold III chloride in acid solutions has been electro-chemically investigated using a cyclic voltammetry technique. This paper emphasizes the current and potential sites at which gold III chloride is reduced in hydrochloric acid that is vital to electrochemical evaluation of gold recovery. The solutions were prepared by reacting HCl with AuCl3 in various concentrations thus 30 and 60 mg/L AuCl3 in 0.1 and 0.5 M HCl, respectively. Solutions of 0.1 and 0.5 M HCl containing 0, 30 and 60 mg/L AuCl3, respectively were tested for possible reduction and oxidation reactions by cyclic voltammogram experiment using a glassy carbon, a saturated calomel and a platinum wire mesh as working, reference and counter electrodes, respectively. The results showed no peak in the case of the absence of AuCl3 in the solutions, but appreciable cathodic and anodic peaks for the reduction and oxidation of various concentrations of AuCl3 in acid solutions. The reaction between AuCl3 and HCl was found to be reversible because the ratio of oxidation peak current and reduction peak current was 1. The concentration of AuCl-4 on the surface of the working electrode at the reduction site for each AuCl3 concentration using Nernst equation was 1.22 × 109 ppm and 2.44 × 109 ppm. The reduction potentials were independent of concentration, while the current was highly dependent of concentration.
基金supported by the National Key Research and Development Program of China (2016YFA202500)the “One Hundred Talent Project” of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (11675255)
文摘Lithium-rich cathode oxides with capability to realize multivalent cationic and anionic redox reactions have attracted much attention as promising candidate electrode materials for high energy density lithium ion batteries because of their ultrahigh specific capacity. However, redox reaction mechanisms, especially for the anionic redox reaction of these materials, are still not very clear. Meanwhile, several pivotal challenges associated with the redox reactions mechanisms, such as structural instability and limited cycle life, hinder the practical applications of these high-capacity lithium-rich cathode oxides. Herein, we review the lithium-rich oxides with various crystal structures. The multivalent cationic/anionic redox reaction mechanisms of several representative high capacity lithium-rich cathode oxides are discussed, attempting to understand the origins of the high lithium storage capacities of these materials. In addition, we provide perspectives for the further development of these lithium-rich cathode oxides based on multivalent cationic and anionic redox reactions, focusing on addressing the fundamental problems and promoting their practical applications.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21273036 and 21177024） and Science ＆ Technology Plan Project of Fujian Province （No. 2014Y2003）.
文摘Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed noble-metal nanoparticles （Au, Pd, Pt） were immobilized on MIL-100（Fe） （denoted M@MIL-100（Fe）） using a facile room-temperature photodeposition technique. The resulting M@MIL-100（Fe） （M = Au, Pd, and Pt） nanocomposites exhibited enhanced photoactivities toward photocatalytic degradation of methyl orange （MO） and reduction of heavy-metal Cr（VI） ions under visible-light irradiation （A ≥ 420 nm） compared with blank-MIL-100（Fe）. Combining these results with photoelectrochemical analyses revealed that noble-metal deposition can effectively improve the charge-separation efficiency of MIL-100（Fe） under visible-light irradiation. This phenomenon in turn leads to the enhancement of visible-light-driven photoactivity of M@MIL-100（Fe） toward photocatalytic redox reactions. In particular, the Pt@MIL-100（Fe） with an average Pt particle size of 2 nm exhibited remarkably enhanced photoactivities compared with those of M@MIL-100（Fe） （M = Au and Pd）, which can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of the photogenerated charge carrier. In addition, possible photocatalytic reaction mechanisms are also proposed.
基金supported by the National Key Research and Development Program of China(Nos.2017YFA0208200 and 2016YFB0700600)the Fundamental Research Funds for the Central Universities of China(No.0205-14380219)+4 种基金the National Natural Science Foundation of China(Nos.22022505,51772258,21872069,and 51761135104)the Natural Science Foundation of Jiangsu Province(Nos.BK20181056,BK20180008,and BK20191042)Jiangsu Postdoctoral Science Fundation(No.2020Z258)Jiangsu Province Cultivation Base for State Key Laboratory of Photovoltaic Science and Technology(No.SKLPST201901)Funding for school-level research projects of Yancheng Institute of Technology(No.xjr2019006).
文摘As one of the high-capacity anodes in lithium-ion batteries(LIBs),silicon oxide(SiOx)has attracted wide attention due to its high theoretical capacity,low cost,and proper working voltage.However,the huge volume change and the intrinsic poor conductivity of SiOx still hinder the practical applications.How to address the issues is the focus of current research.In this work,firstly,hydrogen passivated Si nanosheets(Si6H6)were prepared from Zintl phase CaSi2,then,two-dimensional Ag nanoparticle modified SiOVC nanocomposite was prepared via a facile complex redox reaction between SieH6 and AgN03-aniline complexing agent.In this design,aniline was served as carbon sources,and Si6H6could be transformed to SiOx by AgN03 in mild solution condition.The obtained Ag modified SiOVC(SiOx/C-Ag)electrode exhibited high specific capacity(550 mAh·g^(-1)at 0.6 A·g^(-1)),superior rate,and cycling performance when served as anode for LIBs.
基金supported by the National Natural Science Foundation(NSFC)of China(52002394)Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020006).
文摘The anionic redox reaction(ARR)is a promising charge contributor to improve the reversible capacity of layeredoxide cathodes for Na-ion batteries;however,some practical bottlenecks still need to be eliminated,including a low capacity retention,large voltage hysteresis,and low rate capability.Herein,we proposed a high-Na content honeycomb-ordered cathode,P2–Na_(5/6)[Li_(1/6)Cu_(1/6)Mn_(2/3)]O_(2)(P2-NLCMO),with combined cationic/anionic redox.Neutron powder diffraction and X-ray diffraction of P2-NLCMO suggested P2-type stacking with rarely found P6322 symmetry.In addition,advanced spectroscopy techniques and density functional theory calculations confirmed the synergistic stabilizing relationship between the Li/Cu dual honeycomb centers,achieving fully active Cu^(3+)/Cu^(2+) redox and stabilized ARR with interactively suppressed local distortion.With a meticulously regulated charge/discharge protocol,both the cycling and rate capability of P2-NLCMO were significantly.
基金the support of China Scholarship Council(No.202108430035)G.M.L.acknowledges the Australian Institute of Nuclear Science and Engineering(AINSE)Limited for financial assistance in the form of a Post Graduate Research Award(PGRA)supported by the Australian Research Council(Nos.DP200101862,DP210101486,and FL210100050).
文摘The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries.However,the activation of anionic redox reaction in layered oxides has significant voltage hysteresis and decay that reduce battery performance and limit commercialization.Here,we critically review the up-todate development of anionic redox reaction in layered oxide cathodes,summarize the proposed reaction mechanism,and unveil their connection to voltage hysteresis and decay based on the state-of-the-art progress.In addition,advances associated with various modification approaches to mitigate the voltage hysteresis/decay in layered transition metal oxide cathodes are also included.Finally,we conclude with an appraisal of further research directions including rational design of high-performance layered oxide cathodes with reversible anionic redox reactions and suppressed voltage hysteresis/decay.Findings will be of immediate benefit to the development of layered oxide cathodes for high performance rechargeable batteries.
基金financially supported by the National Natural Science Foundation of China(22271211)the Natural Science Foundation of Shanxi Province(20210302123107 and 202202060301018)。
文摘Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chemical properties,resulting from irreversible oxygen redox reactions and phase transition processes at high voltages,and thus hinder their large-scale application.This work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_(0.7)5Li_(0.25-2/3x)CuxMn_(0.75-1/3x)O_(2)via Cu doping.Ex-situ XPS demonstrates that Cu doping reduces the amount of Mn^(3+)that triggers the Jahn-Teller effect during the cycling.In addition,the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen,and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between O-O.Meanwhile,in-situ XRD results verify that the Na_(0.7)5Li_(0.19)Cu_(0.09)Mn_(0.7)2O_(2)maintains the P2 phase structure during charging and discharging,resulting in a near-zero strain characteristic of 1.9%.Therefore,the optimized cathode delivers a high reversible capacity of 194.9 mAh g−1 at 0.1 C and excellent capacity retention of 88.6%after 100 cycles at 5 C.The full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg−1.Our research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.
基金This work was supported by the Natural Science Foundation of China(22125902,21975243,U2032202,and U1932201)the National Program for Support of Topnotch Young Professionals,the DNL Cooperation Fund,CAS(DNL202020)+2 种基金the Anhui Science Fund for Distinguished Young Scholars(2208085J15)the National Key R&D Program of China(2022YFA1504101)Users with Excellence Program of Hefei Science Center CAS(2021HSC-UE002).
文摘Sulfur redox reactions render lithium–sulfur(Li–S)batteries with an energy density of>500Whkg−1 but suffer a low practical capacity and fast capacity fade due to sluggish sulfur redox reaction(SRR)kinetics,which lies in the complex reaction process that involves a series of reaction intermediates and proceeds via a cascade reaction.Here,we present a Pt–Cu dual-atom catalyst(Pt/Cu-NG)as an electrocatalyst for sulfur redox reactions.Pt/Cu-NG enabled the rapid conversion of soluble polysulfide intermediates into insoluble Li2S2/Li2S,and consequently,it prevented the accumulation and shuttling of lithium polysulfides,thus outperforming the corresponding single-atom catalysts(SACs)with individual Pt or Cu sites.Operando X-ray absorption spectroscopy and density functional theory calculations revealed that a synergistic effect between the paired Pt and Cu atoms modifies the electronic structure of the Pt site through d-orbital interactions,resulting in an optimal moderate interaction of the metal atom with the different sulfide species.This optimal interaction enhanced charge transfer kinetics and promoted sulfur redox reactions.Our work thus provides important insights on the atomic scale into the synergistic effects operative in dual-atom catalysts and will thus pave the way to electrocatalysts with enhanced efficiency for high-performance Li–S batteries.
基金the National Natural Science Foundation of China(grant no.21835007)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(grant no.ZDBS-LY-SLH029)Shanghai Municipal Government S&T Project(grant no.17JC1404701).
文摘Great efforts have been made in investigating the neurotoxicity of dopamine(DA)in the presence of manganous ions.In contrast,here,we probe the possibility of DA-based cancer chemotherapy by leveraging intratumoral redox reactions of DA for producing cytotoxic species in situ.For this purpose,we have constructed a Mn-engineered,DA-loaded nanomedicine.Based on the unique size effect of the nanocarrier,this nanomedicine will not enter the central nervous system but can effectively accumulate in the tumor region,after which the nanocarrier can degrade to release Mn^(2+)and DA in response to the mild acidic intracelluar microenvironment of cancer cells.DA can chelate Mn^(2+)to form a binary coordination complex,where the strong metal-ligand interaction significantly promotes electron delocalization and elevates the reducibility of Mn center,favoring two sequential one-electron oxygen reduction reactions forming H_(2)O_(2),which can be further converted into highly oxidizing ·OH under the cocatalysis by Mn^(2+)and intracellular Fe^(2+).Additionally,as a twoelectron oxidation product of DA ligand,DA-oquinone is potent in exhausting cellular sulfhydryl and depleting reduced glutathione,inhibiting the intrinsic antioxidative mechanism of cancer cells,finally triggering severe oxidative damages in a synergistic manner.It is expected that such a strategy of nanotechnology-mediated metal-ligand coordination and subsequent nontoxicity-to-toxicity transition of DA in tumor may provide a promising prospect for future chemotherapy design.
文摘Subject Code:H30 With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Hu Youcai(胡友财),Prof.Yu Shishan(庾石山)and Prof.Tang Yi(唐奕)from the State Key Laboratory of Bioactive Substance and Function of Natural Medicines,Institute
基金financial support from the Natural Science Foundation of China(22125902,21975243,and U2032202)the Anhui Science Fund for Distinguished Young Scholars(2208085J15)+2 种基金the National Key R&D Program of China(2022YFA1504101)Users with Excellence Program of Hefei Science Center CAS(2021HSC-UE002)the USTC Research Funds of the Double First-Class Initiative(YD2060002030).
文摘CONSPECTUS:Lithium−sulfur(Li-S)batteries have emerged as a promising energy storage technology driven by their potential to reach very high theoretical specific energy densities of up to 2600 Wh·kg^(−1).This remarkably high energy density directly results from the reversible,multi-electron-transfer reactions between sulfur and lithium metal taking place during the charge and discharge cycles.However,the charge/discharge processes of Li-S batteries are invariably accompanied by changes in both the composition and the structure of the sulfur species in the cathode,all of which result in sluggish and incomplete sulfur transformation.It has been demonstrated that the application of electrocatalysts is an effective strategy to accelerate the sulfur reduction reaction(SRR).Recognizing this challenge,researchers worldwide have tried to develop efficient catalysts to accelerate the kinetics of the SRR and boost the overall performance of Li-S batteries.However,this goal necessitates an in-depth understanding of the intricate catalytic processes in the Li-S battery cathode.The effective characterization of the catalysts and a thorough investigation of the SRR process are essential steps to unraveling the underlying catalytic mechanism of sulfur reduction and to compare the performances of the different electrocatalysts.Nonetheless,this pursuit is hindered by the inherent complexity of the SRR process,which remains uniquely specific to the Li-S system under study.Throughout the SRR process,a multitude of intermediate products are created through catalytic conversions between liquid−solid and solid−solid phases.This complexity is markedly different from established heterogeneous catalytic processes,such as water-splitting reactions,where reactants,products,and reaction phases are relatively simple.Given these challenges,our response has been to design a series of catalysts with controlled structures to gain an in-depth understanding of the intricate reaction processes within Li-S catalysis.In this Account,we have undertaken a comprehensive analysis of the structure−function relationships governing the active sites of electrocatalysts in SRR.Our work thus encompasses three aspects-catalytic sites:their geometry and evolution during the reaction,catalytic mechanisms:a key factor that determines SRR kinetics,and catalytic materials:intelligent design toward optimized performance.Also presented in this Account is a brief discussion covering the broader domain of other electrocatalysts and sulfurbased electrochemical systems.Drawing upon the insights obtained from these works,we present future perspectives on potential opportunities and hurdles in the wider application of sulfur cathode electrocatalysts.
