Experts and officials shared their insights on poverty reduction cooperation and sustainable development during the 2025 International Seminar on Global Poverty Reduction Partnerships.
Controllable synthesis of ultrathin metallene nanosheets and rational design of their spatial arrangement in favor of electrochemical catalysis are critical for their renewable energy applications.Here,a biomimetic de...Controllable synthesis of ultrathin metallene nanosheets and rational design of their spatial arrangement in favor of electrochemical catalysis are critical for their renewable energy applications.Here,a biomimetic design of“Trunk-Branch-Leaf”strategy is proposed to prepare the ultrathin edge-riched Zn-ene“leaves”with a thickness of~2.5 nm,adjacent Zn-ene cross-linked with each other,which are supported by copper nanoneedle“branches”on copper mesh“trunks,”named as Zn-ene/Cu-CM.The resulting superstructure enables the formation of an interconnected network and multiple channels,which can be used as an electrocatalytic CO_(2) reduction reaction(CO_(2)RR)electrode to allow a fast charge and mass transfer as well as a large electrolyte reservoir.By virtue of the distinctive structure,the obtained Zn-ene/Cu-CM electrode exhibits excellent selectivity and activity toward CO production with a maximum Faradaic efficiency of 91.3%and incredible partial current density up to 40 mA cm^(−2),outperforming most of the state-of-the-art Zn-based electrodes for CO_(2) reduction.The phenolphthalein color probe combined with in situ attenuated total reflection-infrared spectroscopy uncovered the formation of the localized pseudo-alkaline microenvironment at the interface of the Zn-ene/Cu-CM electrode.Theoretical calculations confirmed that the localized pH as the origin is responsible for the adsorption of CO_(2) at the interface and the generation of *COOH and *CO intermediates.This study offers valuable insights into developing efficient electrodes through synergistic regulation of reaction microenvironments and active sites,thereby facilitating the electrolysis of practical CO_(2) conversion.展开更多
The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a serie...The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a series of RuCo/C catalysts were synthesized by NaBH4 reduction method under the premise that the total metal mass percentage was 20%.X-ray diffraction(XRD)patterns and scanning electron microscopy(SEM)confirmed the formation of single-phase nanoparticles with an average size of 33 nm.Cyclic voltammograms(CV)and linear sweep voltammograms(LSV)tests indicated that RuCo(2:1)/C catalyst had the optimal ORR properties.Additionally,the RuCo(2:1)/C catalyst remarkably sustained 98.1% of its activity even after 3000 cycles,surpassing the performance of Pt/C(84.8%).Analysis of the elemental state of the catalyst surface after cycling using X-ray photoelectron spectroscopy(XPS)revealed that the Ru^(0) percentage of RuCo(2:1)/C decreased by 2.2%(from 66.3% to 64.1%),while the Pt^(0) percentage of Pt/C decreased by 7.1%(from 53.3% to 46.2%).It is suggested that the synergy between Ru and Co holds the potential to pave the way for future low-cost and highly stable ORR catalysts,offering significant promise in the context of PEMFCs.展开更多
Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-...Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-doped carbon(Fe/SNC)via in situ incorporation of 2-aminothiazole molecules into zeolitic imidazolate framework-8(ZIF-8)through coordination between metal ions and organic ligands.Sulfur and nitrogen doping in carbon supports effectively modulates the electronic structure of the catalyst,increases the Brunauer-Emmett-Teller surface area,and exposes more Fe-N_(x)active centers.Fe-loaded,S and N co-doped carbon with Fe/S molar ratio of 1:10(Fe/SNC-10)exhibits a half-wave potential of 0.902 V vs.RHE.After 5000 cycles of cyclic voltammetry,its half-wave potential decreases by only 20 mV vs.RHE,indicating excellent stability.Due to sulfur s lower electronegativity,the electronic structure of the Fe-N_(x)active center is modulated.Additionally,the larger atomic radius of sulfur introduces defects into the carbon support.As a result,Fe/SNC-10 demonstrates superior ORR activity and stability in alkaline solution compared with Fe-loaded N-doped carbon(Fe/NC).Furthermore,the zinc-air battery assembled with the Fe/SNC-10 catalyst shows enhanced performance relative to those assembled with Fe/NC and Pt/C catalysts.This work offers a novel design strategy for advanced energy storage and conversion applications.展开更多
Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespr...Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespread attention for CO_(2)RR due to their high catalytic activity,selectivity,excellent stability,and low cost.However,they still need to be further improved to meet the needs of industrial applications.This review article comprehensively summarizes the recent advances in regulation strategies of Bi-based catalysts and can be divided into six categories:(1)defect engineering,(2)atomic doping engineering,(3)organic framework engineering,(4)inorganic heterojunction engineering,(5)crystal face engineering,and(6)alloying and polarization engineering.Meanwhile,the corresponding catalytic mechanisms of each regulation strategy will also be discussed in detail,aiming to enable researchers to understand the structure-property relationship of the improved Bibased catalysts fundamentally.Finally,the challenges and future opportunities of the Bi-based catalysts in the photoelectrocatalytic CO_(2)RR application field will also be featured from the perspectives of the(1)combination or synergy of multiple regulatory strategies,(2)revealing formation mechanism and realizing controllable synthesis,and(3)in situ multiscale investigation of activation pathways and uncovering the catalytic mechanisms.On the one hand,through the comparative analysis and mechanism explanation of the six major regulatory strategies,a multidimensional knowledge framework of the structure-activity relationship of Bi-based catalysts can be constructed for researchers,which not only deepens the atomic-level understanding of catalytic active sites,charge transport paths,and the adsorption behavior of intermediate products,but also provides theoretical guiding principles for the controllable design of new catalysts;on the other hand,the promising collaborative regulation strategies,controllable synthetic paths,and the in situ multiscale characterization techniques presented in this work provides a paradigm reference for shortening the research and development cycle of high-performance catalysts,conducive to facilitating the transition of photoelectrocatalytic CO_(2)RR technology from the laboratory routes to industrial application.展开更多
Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction...Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction(ORR)and chlorideinduced degradation over conventional catalysts.In this study,we proposed a universal synthetic strategy to construct heteroatom axially coordinated Fe–N_(4) single-atom seawater catalyst materials(Cl–Fe–N_(4) and S–Fe–N_(4)).X-ray absorption spectroscopy confirmed their five-coordinated square pyramidal structure.Systematic evaluation of catalytic activities revealed that compared with S–Fe–N_(4),Cl–Fe–N_(4) exhibits smaller electrochemical active surface area and specific surface area,yet demonstrates higher limiting current density(5.8 mA cm^(−2)).The assembled zinc-air batteries using Cl–Fe–N_(4) showed superior power density(187.7 mW cm^(−2) at 245.1 mA cm^(−2)),indicating that Cl axial coordination more effectively enhances the intrinsic ORR activity.Moreover,Cl–Fe–N_(4) demonstrates stronger Cl−poisoning resistance in seawater environments.Chronoamperometry tests and zinc-air battery cycling performance evaluations confirmed its enhanced stability.Density functional theory calculations revealed that the introduction of heteroatoms in the axial direction regulates the electron center of Fe single atom,leading to more active reaction intermediates and increased electron density of Fe single sites,thereby enhancing the reduction in adsorbed intermediates and hence the overall ORR catalytic activity.展开更多
Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when ta...Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when tackling high-dimensional optimization challenges.To effectively address these challenges,this study introduces cooperative metaheuristics integrating dynamic dimension reduction(DR).Building upon particle swarm optimization(PSO)and differential evolution(DE),the proposed cooperative methods C-PSO and C-DE are developed.In the proposed methods,the modified principal components analysis(PCA)is utilized to reduce the dimension of design variables,thereby decreasing computational costs.The dynamic DR strategy implements periodic execution of modified PCA after a fixed number of iterations,resulting in the important dimensions being dynamically identified.Compared with the static one,the dynamic DR strategy can achieve precise identification of important dimensions,thereby enabling accelerated convergence toward optimal solutions.Furthermore,the influence of cumulative contribution rate thresholds on optimization problems with different dimensions is investigated.Metaheuristic algorithms(PSO,DE)and cooperative metaheuristics(C-PSO,C-DE)are examined by 15 benchmark functions and two engineering design problems(speed reducer and composite pressure vessel).Comparative results demonstrate that the cooperative methods achieve significantly superior performance compared to standard methods in both solution accuracy and computational efficiency.Compared to standard metaheuristic algorithms,cooperative metaheuristics achieve a reduction in computational cost of at least 40%.The cooperative metaheuristics can be effectively used to tackle both high-dimensional unconstrained and constrained optimization problems.展开更多
Accelerated industrialization combined with over-applied nitrogen fertilizers results in serious nitrate pollution insurface and ground water,disrupting the balance of the global nitrogen cycle.Electrochemical nitrate...Accelerated industrialization combined with over-applied nitrogen fertilizers results in serious nitrate pollution insurface and ground water,disrupting the balance of the global nitrogen cycle.Electrochemical nitrate reduction(eNO_(3)RR)emerges as an attractive strategy to simultaneously enable nitrate removal and decentralized ammo-nia fabrication,restoring the globally perturbed nitrogen cycle.However,complex deoxygenation-hydrogenationprocesses and sluggish proton-electron transfer kinetics significantly hinder practical application of eNO_(3)RR.In this study,we developed carbon-coated Cu-Ni bimetallic catalysts derived from metal-organic frameworks(MOFs)to facilitate eNO_(3)RR.The unique structural features of catalyst promote enhanced synergy between Cuand Ni,effectively addressing critical challenges in nitrate reduction.Comprehensive structural and electrochem-ical analysis demonstrate that electrochemical nitrate-to-nitrite conversion mainly takes place on active Cu sites,the introduction of Ni could efficiently accelerate the generation of aquatic active hydrogen,promoting the hy-drogenation of oxynitrides during eNO_(3)RR.In addition,Ni introduction could push up the d-band center of thecatalyst,thus enhancing the adsorption and activation of nitrate and the corresponding intermediates.Detailedreaction pathways for nitrate-to-ammonia conversion are illuminated by rotating disk electrode(RDE),in-situFourier-transform infrared spectroscopy,in-situ Raman spectrum and electrochemical impedance spectroscopy(EIS).Benefiting from the synergistic effect of Cu and Ni,optimum catalyst exhibited excellent nitrate reductionperformance.This work provides a new idea for elucidating the underlying eNO_(3)RR reaction mechanisms andcontributes a promising strategy for designing efficient bimetallic electrocatalysts.展开更多
Fe reducing bacteria(FRB),through extracellular electron transfer(EET)pathway,can reduce Fe(III)nanoparticles,thereby affecting the migration,transformation,and degradation of pollutants.However,the interaction of Fe(...Fe reducing bacteria(FRB),through extracellular electron transfer(EET)pathway,can reduce Fe(III)nanoparticles,thereby affecting the migration,transformation,and degradation of pollutants.However,the interaction of Fe(III)nanoparticles with the most commonly identified FRB,Geobacter sulfurreducens PCA,remains poorly understood.Herein,we demonstrated that the synergistic role of outer membrane proteins and periplasmic proteins in the EET process for-Fe_(2)O_(3),Fe3O4,and𝛽α-FeOOH nanoparticles by construction of multiple gene knockout strain.oxpG(involved in the type II secretion system)and omcST(outer membrane c-type cytochrome)medi-ated pathways accounted for approximately 67%of the total reduction of𝛼α-Fe_(2)O_(3) nanoparticles.The residual reduction of𝛼α-Fe_(2)O_(3) nanoparticles in∆oxpG-omcST strain was likely caused by redox-active substances in cell supernatant.Conversely,the reduction of dissolved Fe(III)was almost unaffected in∆oxpG-omcST strain at the same concentration.However,at high dissolved Fe(III)concentration,the reduction significantly decreased due to the formation of Fe(III)nanoparticles,suggesting that this EET process is specific to Fe(III)nanoparticles.Overall,our study provided a more comprehensive understanding for the EET pathways between G.sulfurreducens PCA and different Fe(III)species,enriching our knowledge on the role of microorganisms in iron biogeochemical cycles and remediation strategies of pollutants.展开更多
This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solito...This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solitons propagating against a Painlevé wave background,in analogy to the established notion of elliptic solitons,which refers to solitons on an elliptic wave background.By employing a novel symmetry decomposition method aided by nonlocal residual symmetries,we explicitly construct (extended) Painlevé Ⅱ solitons for the Korteweg-de Vries equation and (extended) Painlevé Ⅳ solitons for the Boussinesq equation.展开更多
It is an important way to realize low carbon in China’s iron and steel industry by hydrogen-rich blast furnace smelting process.Sinter is the main blast furnace burden,and its reduction characteristics have a signifi...It is an important way to realize low carbon in China’s iron and steel industry by hydrogen-rich blast furnace smelting process.Sinter is the main blast furnace burden,and its reduction characteristics have a significant influence on ironmaking.The reduction behaviors,including reduction index(RI)and low-temperature reduction disintegration index(RDI),and the reduction mechanism of sinter in hydrogen-rich blast furnace were investigated.The results show that RI increased from 82.85 to 95.53 wt.%with an increase in H_(2)content from 0 to 30 vol.%,and the main phase of the reduction product was metallic iron.In the research of RDI,when the H_(2)content was increased from 0 to 20 vol.%,RDI+3.15 increased from 69.61 to 75.38 wt.%,and the main reaction was the reduction of hematite to magnetite.At 600-950℃,the reduction of sinter in CO and hydrogen-rich atmospheres(H_(2):CO=2)was both controlled by the first-order reaction model,and the apparent activation energy was 33.64 and 44.57 kJ/mol,respectively.展开更多
To recover the valuable elements in Bayan Obo tailings,Fe-Si bath smelting reduction was adopted to separate and enrich rare earth elements(REE),niobium and titanium from the REE-Nb-Ti-containing slag.The reduction re...To recover the valuable elements in Bayan Obo tailings,Fe-Si bath smelting reduction was adopted to separate and enrich rare earth elements(REE),niobium and titanium from the REE-Nb-Ti-containing slag.The reduction reaction process of the Fe-Si bath and the migration behavior of valuable elements in the solidification and crystallization process of silicothermic reduction tailings were investigated,and a treatment method for efficiently separating and enriching REE,Nb and Ti was explored.Thermodynamic analysis indicated that at 1600℃,with a 6 wt.%addition of Si as the reducing agent,the niobium oxide in the REE-Nb-Ti-containing slag could be selectively reduced to metallic Nb.In the Fe-Si bath reduction process,the Nb mass fraction in the metal phase increased with prolonged reaction time,peaking at 2.77%,while the Ti mass fraction consistently stayed below 0.12%.Lowering the w(CaO)/w(SiO_(2))enhanced the migration of Nb from slag to metal phase and reduced the Ti impurities.During solidification and crystallization,a significant quantity of perovskite precipitated from reduction tailings,with the REE dissolving into this perovskite.By adjusting the w(CaO)/w(SiO_(2))in tailings to 1.2-1.9 and maintaining a temperature of 1100℃for 4 h,the perovskite area fraction in the final slag could exceed 37%.Finally,a method was proposed to separate and enrich valuable elements in REE-Nb-Ti-containing slags via Fe-Si bath smelting reduction and crystallization control.展开更多
The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large de...The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large deformation during the LCR process and to minimize the thickness of the slab in bending segments,the maximum theoretical reduction amount and the corresponding reduction scheme for the LCR process must be determined.With SPA-H weathering steel as a specific research steel grade,the distributions of tem-perature and deformation fields of a slab with the LCR process were analyzed using a three-dimensional thermal-mechanical finite ele-ment model.High-temperature tensile tests were designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperatures,and a prediction model of the critical strain for two typical cracks,combining the effects of strain rate and temperature,was proposed by incorporating the Zener-Hollomon parameter.The crack risks with different LCR schemes were calculated using the crack risk prediction model,and the maximum theoretical reduction amount for the SPA-H slab with a transverse section of 145 mm×1600 mm was 41.8 mm,with corresponding reduction amounts for Segment 0 to Segment 4 of 15.8,7.3,6.5,6.4,and 5.8 mm,respectively.展开更多
The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path an...The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path and the low reactive species(nitrate and proton)concentration at the catalyst interface inhibit the efficiency of ammonia production from nitrate reduction reaction(NitRR).Herein,we introduce a novel iron-based tandem catalyst encapsulated by reduced graphene oxide(denoted as Fe-rGO),with a superior ammonia production rate of 47.815 mg h^(-1)mg_(ca)^(t-1)and a high Faraday efficiency(FE)of 96.51%at an applied potential of-0.5 V.It also delivers a robust stability with FE above90%under a current density of 250 mA cm^(-2)for 50 h.In situ X-ray absorption spectroscopy reveals that the FeO_(x)is dynamically translated to Fe~0 site concurrently with the enhancement of the NH_(3)production rate,suggesting the Fe^(0) site as hydrogenation active center.The asymmetric distribution of surface charges of rGO not only enriches nitrate ions at the catalytic interface and promotes the hydrogenation process in NitRR,but also protects the iron species and ensures their stability during electrolysis.The Zn-NO_(3)^(-)battery demonstrates an impressive FE of 88.6%,highlighting its exceptional potential for practical applications.展开更多
The solid-state reduction kinetics of pre-oxidized vanadium-titanium magnetite concentrate was studied. The phase and microstructure of the reduction product were characterized by XRD, SEM and EDS methods, based on wh...The solid-state reduction kinetics of pre-oxidized vanadium-titanium magnetite concentrate was studied. The phase and microstructure of the reduction product were characterized by XRD, SEM and EDS methods, based on which the mechanism of the solid-state reduction was investigated. The results showed that using coal as reductant at 950-1100 °C, the solid-state reduction of the pre-oxidized vanadium-titanium magnetite concentrate was controlled by interface chemical reaction and the apparent activation energy was 67.719 k J/mol. The mineral phase transformation during the reduction process can be described as follows： pre-oxidized vanadium-titanium magnetite concentrate → ulvospinel → ilmenite → Fe Ti2O5 →（FenTi1-n）Ti2O5. M3O5-type（M can be Fe, Ti, Mg, Mn, etc） solid solutions would be formed during the reduction process of the pre-oxidized vanadium-titanium magnetite concentrate at 1050 °C for 60 min. The poor reducibility of iron in M3O5 solid solutions is the main reason to limit the reduction property of pre-oxidized vanadium-titanium magnetite concentrate.展开更多
Iron ore pellets,as one of the main charges of blast furnaces,have a greater impact on the CO_(2)emission reduction and stable operation of blast furnaces.The isothermal reduction behavior of the pellets obtained from...Iron ore pellets,as one of the main charges of blast furnaces,have a greater impact on the CO_(2)emission reduction and stable operation of blast furnaces.The isothermal reduction behavior of the pellets obtained from a Chinese steel plant was studied in the gas mixtures of CO and N_(2).The results showed the reduction process is divided into two stages.The reduction in the initial stage(time t≤40 min)is cooperatively controlled by internal diffusion and interface chemical reactions with the activation energy of 30.19 and 16.67 kJ/mol,respectively.The controlling step of the reduction in the final stage(t>40 min)is internal diffusion with the activation energy of 34.60 kJ/mol.The reduction process can be described by two equations obtained from kinetic calculations.The reduction degree can be predicted under different temperatures and time,and the predicted results showed an excellent correlation with the experimental results.The reduction mechanisms were confirmed by the analysis of the scanning electron microscope equipped with an energy dispersive spectrometer and optical microscope.展开更多
Long-bone fractures are common complaints in orthopedic surgery.In recent years,significant progress has been made in robot-assisted fracture-reduction techniques.As a key medical device for diverse fracture morpholog...Long-bone fractures are common complaints in orthopedic surgery.In recent years,significant progress has been made in robot-assisted fracture-reduction techniques.As a key medical device for diverse fracture morphologies and sites,the design of the reduction robot has a profound impact on the reduction outcomes.However,existing reduction robots have practical limitations and cannot simultaneously satisfy clinical requirements in terms of workspace,force/torque,and structural stiffness.To overcome these problems,we first analyze the potential placement areas and performance requirements of reduction robots according to clinical application scenarios.Subsequently,a 3UPS/S-3P hybrid configuration with decoupled rotational and translational degrees of freedom(DOFs)is proposed,and a kinematic model is derived to achieve the motion characteristics of the remote center of motion(RCM).Furthermore,the structural design of a hybrid reduction robot with an integrated distal clamp and proximal fixator was completed,and a mechanical prototype was constructed.The results of the performance evaluations and static analysis demonstrate that the proposed reduction robot has acceptable workspace,force,and torque performance and excellent structural stiffness.Two clinical case simulations further demonstrated the clinical feasibility of the robot.Finally,preliminary experiments on bone models demonstrated the potential effectiveness of the proposed reduction robot in lower-limb fracture reduction.展开更多
Electrochemical nitrate reduction(eNO_(3)RR)and nitric oxide reduction(eNORR)to ammonia have emerged as promising and sustainable alternatives to the traditional Haber-Bosch method for ammonia production,particularly ...Electrochemical nitrate reduction(eNO_(3)RR)and nitric oxide reduction(eNORR)to ammonia have emerged as promising and sustainable alternatives to the traditional Haber-Bosch method for ammonia production,particularly within the recently proposed reverse artificial nitrogen cycle route:N_(2)→NO_(x)→NH_(3).Notably,experimental studies have demonstrated that eNORR exhibits superior performance over eNO_(3)RR on Cu6Sn5 catalysts.However,the fundamental mechanisms underlying this difference remain poorly understood.Herein,we performed systematic theoretical calculations to explore the reaction pathways,electronic structure effects,and potential-dependent Faradic efficiency associated with ammonia production via these two distinct electrochemical pathways(eNORR and eNO_(3)RR)on Cu6Sn5.By implementing an advanced‘adaptive electric field controlled constant potential(EFC-CP)’methodology combined with microkinetic modeling,we successfully reproduced the experimental observations and identified the key factors affecting ammonia production in both reaction pathways.It was found that eNORR outperforms eNO_(3)RR because it circumvents the ^(*)NO_(2) dissociation and ^(*)NO_(2) desorption steps,leading to distinct surface coverage of key intermediates between the two pathways.Furthermore,the reaction rates were found to exhibit a pronounced dependence on the surface coverage of ^(*)NO in eNORR and ^(*)NO_(2) in eNO_(3)RR.Specifically,the facile desorption of ^(*)NO_(2) on the Cu6Sn5 surface in eNO_(3)RR limits the attainable surface coverage of ^(*)NO,thereby impeding its performance.In contrast,the eNORR can maintain a high surface coverage of adsorbed ^(*)NO species,contributing to its enhanced ammonia production performance.These fundamental insights provide valuable guidance for the rational design of catalysts and the optimization of reaction routes,facilitating the development of more efficient,sustainable,and scalable techniques for ammonia production.展开更多
To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that th...To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that the MgO addition decreased the reduction swelling index(RSI)and reduction degree of pellets in both CO and H_(2)atmospheres.During the stepwise reduction process of Fe2O3→Fe3O4→FeO,the reduction behaviour of pellets in CO and H_(2)was similar,while the reduction rate of pellets in H_(2)atmosphere was almost twice as high as that in CO atmosphere.During the stepwise reduction process of FeO→Fe,the RSI of pellets showed a logarithmic increase in CO atmosphere and a linear decrease in H_(2)atmosphere.As investigated by first-principles calculations,C and Fe mainly formed chemical bonds,and the CO reduction process released energy,promoting the formation of iron whiskers.However,H and Fe produced weak physical adsorption,and the H_(2)reduction process was endothermic,inhibiting the generation of iron whiskers.With Mg2+doping in FexO,the nucleation region of iron whiskers expanded in CO reduction process,and the morphology of iron whiskers transformed from“slender”to“stocky,”reducing RSI of the pellets.展开更多
Microwave pre-oxidation and biomass reduction were adopted to enhance the separation of titanium and iron in vanadium-titanium magnetite.The effects of microwave pre-oxidation temperature and time,as well as biomass r...Microwave pre-oxidation and biomass reduction were adopted to enhance the separation of titanium and iron in vanadium-titanium magnetite.The effects of microwave pre-oxidation temperature and time,as well as biomass reduction temperature and time,were investigated.The results showed that the average particle size of vanadium-titanium magnetite decreased,and the specific surface area increased with the increase in pre-oxidation temperature and time.The reaction pathway(Fe_(3-x)TixO_(4)→Fe_(2-x)TixO_(3)→Fe_(2)TiO_(5))was proved in microwave pre-oxidation process.The results of biomass reduction roasting showed that biomass reduction could effectively reduce ferric oxide to metallic iron while Ti was enriched in a solid solution of magnesium anosovite,which was beneficial to the subsequent grinding and acid leaching separation.The combined process of microwave pre-oxidation and biomass reduction achieved a high separation efficiency of titanium and iron in vanadium-titanium magnetite without forming complex titanium minerals.The titanium grade in the vanadium-titanium-rich material was 32.10%,and the recovery rate was 91.51%.The iron grade in the iron concentrate(metallic iron)was 90.90%,the recovery rate was 93.47%,and metallization rate was 93.87%.展开更多
文摘Experts and officials shared their insights on poverty reduction cooperation and sustainable development during the 2025 International Seminar on Global Poverty Reduction Partnerships.
基金supports of the National Natural Science Foundation of China(NSFC)(52021004,52394202)key project of the Joint Fund for Innovation and Development of Chongqing Natural Science Foundation(CSTB2022NSCQ-LZX0013)+1 种基金the National Natural Science Foundation of China(NSFC)(52301232,and 52476056)the Natural Science Foundation of Chongqing Province(2024NSCQ-MSX1109).
文摘Controllable synthesis of ultrathin metallene nanosheets and rational design of their spatial arrangement in favor of electrochemical catalysis are critical for their renewable energy applications.Here,a biomimetic design of“Trunk-Branch-Leaf”strategy is proposed to prepare the ultrathin edge-riched Zn-ene“leaves”with a thickness of~2.5 nm,adjacent Zn-ene cross-linked with each other,which are supported by copper nanoneedle“branches”on copper mesh“trunks,”named as Zn-ene/Cu-CM.The resulting superstructure enables the formation of an interconnected network and multiple channels,which can be used as an electrocatalytic CO_(2) reduction reaction(CO_(2)RR)electrode to allow a fast charge and mass transfer as well as a large electrolyte reservoir.By virtue of the distinctive structure,the obtained Zn-ene/Cu-CM electrode exhibits excellent selectivity and activity toward CO production with a maximum Faradaic efficiency of 91.3%and incredible partial current density up to 40 mA cm^(−2),outperforming most of the state-of-the-art Zn-based electrodes for CO_(2) reduction.The phenolphthalein color probe combined with in situ attenuated total reflection-infrared spectroscopy uncovered the formation of the localized pseudo-alkaline microenvironment at the interface of the Zn-ene/Cu-CM electrode.Theoretical calculations confirmed that the localized pH as the origin is responsible for the adsorption of CO_(2) at the interface and the generation of *COOH and *CO intermediates.This study offers valuable insights into developing efficient electrodes through synergistic regulation of reaction microenvironments and active sites,thereby facilitating the electrolysis of practical CO_(2) conversion.
基金Funded by the 111 Project(No.B17034)Open Project of Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle(No.ZDSYS202212)+1 种基金Innovative Research Team Development Program of Ministry of Education of China(No.IRT_17R83)the Science and Technology Project of China Southern Power Grid Co.,Ltd.(No.GDKJXM20222546)。
文摘The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a series of RuCo/C catalysts were synthesized by NaBH4 reduction method under the premise that the total metal mass percentage was 20%.X-ray diffraction(XRD)patterns and scanning electron microscopy(SEM)confirmed the formation of single-phase nanoparticles with an average size of 33 nm.Cyclic voltammograms(CV)and linear sweep voltammograms(LSV)tests indicated that RuCo(2:1)/C catalyst had the optimal ORR properties.Additionally,the RuCo(2:1)/C catalyst remarkably sustained 98.1% of its activity even after 3000 cycles,surpassing the performance of Pt/C(84.8%).Analysis of the elemental state of the catalyst surface after cycling using X-ray photoelectron spectroscopy(XPS)revealed that the Ru^(0) percentage of RuCo(2:1)/C decreased by 2.2%(from 66.3% to 64.1%),while the Pt^(0) percentage of Pt/C decreased by 7.1%(from 53.3% to 46.2%).It is suggested that the synergy between Ru and Co holds the potential to pave the way for future low-cost and highly stable ORR catalysts,offering significant promise in the context of PEMFCs.
基金financial support of the National Natural Science Foundation of China(No.52472271)the National Key Research and Development Program of China(No.2023YFE0115800)。
文摘Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-doped carbon(Fe/SNC)via in situ incorporation of 2-aminothiazole molecules into zeolitic imidazolate framework-8(ZIF-8)through coordination between metal ions and organic ligands.Sulfur and nitrogen doping in carbon supports effectively modulates the electronic structure of the catalyst,increases the Brunauer-Emmett-Teller surface area,and exposes more Fe-N_(x)active centers.Fe-loaded,S and N co-doped carbon with Fe/S molar ratio of 1:10(Fe/SNC-10)exhibits a half-wave potential of 0.902 V vs.RHE.After 5000 cycles of cyclic voltammetry,its half-wave potential decreases by only 20 mV vs.RHE,indicating excellent stability.Due to sulfur s lower electronegativity,the electronic structure of the Fe-N_(x)active center is modulated.Additionally,the larger atomic radius of sulfur introduces defects into the carbon support.As a result,Fe/SNC-10 demonstrates superior ORR activity and stability in alkaline solution compared with Fe-loaded N-doped carbon(Fe/NC).Furthermore,the zinc-air battery assembled with the Fe/SNC-10 catalyst shows enhanced performance relative to those assembled with Fe/NC and Pt/C catalysts.This work offers a novel design strategy for advanced energy storage and conversion applications.
基金supports from the National Natural Science Foundation of China(Grant Nos.12305372 and 22376217)the National Key Research&Development Program of China(Grant Nos.2022YFA1603802 and 2022YFB3504100)+1 种基金the projects of the key laboratory of advanced energy materials chemistry,ministry of education(Nankai University)key laboratory of Jiangxi Province for persistent pollutants prevention control and resource reuse(2023SSY02061)are gratefully acknowledged.
文摘Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespread attention for CO_(2)RR due to their high catalytic activity,selectivity,excellent stability,and low cost.However,they still need to be further improved to meet the needs of industrial applications.This review article comprehensively summarizes the recent advances in regulation strategies of Bi-based catalysts and can be divided into six categories:(1)defect engineering,(2)atomic doping engineering,(3)organic framework engineering,(4)inorganic heterojunction engineering,(5)crystal face engineering,and(6)alloying and polarization engineering.Meanwhile,the corresponding catalytic mechanisms of each regulation strategy will also be discussed in detail,aiming to enable researchers to understand the structure-property relationship of the improved Bibased catalysts fundamentally.Finally,the challenges and future opportunities of the Bi-based catalysts in the photoelectrocatalytic CO_(2)RR application field will also be featured from the perspectives of the(1)combination or synergy of multiple regulatory strategies,(2)revealing formation mechanism and realizing controllable synthesis,and(3)in situ multiscale investigation of activation pathways and uncovering the catalytic mechanisms.On the one hand,through the comparative analysis and mechanism explanation of the six major regulatory strategies,a multidimensional knowledge framework of the structure-activity relationship of Bi-based catalysts can be constructed for researchers,which not only deepens the atomic-level understanding of catalytic active sites,charge transport paths,and the adsorption behavior of intermediate products,but also provides theoretical guiding principles for the controllable design of new catalysts;on the other hand,the promising collaborative regulation strategies,controllable synthetic paths,and the in situ multiscale characterization techniques presented in this work provides a paradigm reference for shortening the research and development cycle of high-performance catalysts,conducive to facilitating the transition of photoelectrocatalytic CO_(2)RR technology from the laboratory routes to industrial application.
基金funded by the Innovative Research Group Project of the National Natural Science Foundation of China(52121004)the Research Development Fund(No.RDF-21-02-060)by Xi’an Jiaotong-Liverpool University+1 种基金support received from the Suzhou Industrial Park High Quality Innovation Platform of Functional Molecular Materials and Devices(YZCXPT2023105)the XJTLU Advanced Materials Research Center(AMRC).
文摘Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction(ORR)and chlorideinduced degradation over conventional catalysts.In this study,we proposed a universal synthetic strategy to construct heteroatom axially coordinated Fe–N_(4) single-atom seawater catalyst materials(Cl–Fe–N_(4) and S–Fe–N_(4)).X-ray absorption spectroscopy confirmed their five-coordinated square pyramidal structure.Systematic evaluation of catalytic activities revealed that compared with S–Fe–N_(4),Cl–Fe–N_(4) exhibits smaller electrochemical active surface area and specific surface area,yet demonstrates higher limiting current density(5.8 mA cm^(−2)).The assembled zinc-air batteries using Cl–Fe–N_(4) showed superior power density(187.7 mW cm^(−2) at 245.1 mA cm^(−2)),indicating that Cl axial coordination more effectively enhances the intrinsic ORR activity.Moreover,Cl–Fe–N_(4) demonstrates stronger Cl−poisoning resistance in seawater environments.Chronoamperometry tests and zinc-air battery cycling performance evaluations confirmed its enhanced stability.Density functional theory calculations revealed that the introduction of heteroatoms in the axial direction regulates the electron center of Fe single atom,leading to more active reaction intermediates and increased electron density of Fe single sites,thereby enhancing the reduction in adsorbed intermediates and hence the overall ORR catalytic activity.
基金funded by National Natural Science Foundation of China(Nos.12402142,11832013 and 11572134)Natural Science Foundation of Hubei Province(No.2024AFB235)+1 种基金Hubei Provincial Department of Education Science and Technology Research Project(No.Q20221714)the Opening Foundation of Hubei Key Laboratory of Digital Textile Equipment(Nos.DTL2023019 and DTL2022012).
文摘Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when tackling high-dimensional optimization challenges.To effectively address these challenges,this study introduces cooperative metaheuristics integrating dynamic dimension reduction(DR).Building upon particle swarm optimization(PSO)and differential evolution(DE),the proposed cooperative methods C-PSO and C-DE are developed.In the proposed methods,the modified principal components analysis(PCA)is utilized to reduce the dimension of design variables,thereby decreasing computational costs.The dynamic DR strategy implements periodic execution of modified PCA after a fixed number of iterations,resulting in the important dimensions being dynamically identified.Compared with the static one,the dynamic DR strategy can achieve precise identification of important dimensions,thereby enabling accelerated convergence toward optimal solutions.Furthermore,the influence of cumulative contribution rate thresholds on optimization problems with different dimensions is investigated.Metaheuristic algorithms(PSO,DE)and cooperative metaheuristics(C-PSO,C-DE)are examined by 15 benchmark functions and two engineering design problems(speed reducer and composite pressure vessel).Comparative results demonstrate that the cooperative methods achieve significantly superior performance compared to standard methods in both solution accuracy and computational efficiency.Compared to standard metaheuristic algorithms,cooperative metaheuristics achieve a reduction in computational cost of at least 40%.The cooperative metaheuristics can be effectively used to tackle both high-dimensional unconstrained and constrained optimization problems.
基金supported by the Natural Science Foundation of China(No.52101279)the Key Scientific Research Foundation of Education department of Hunan Province(No.24A0003)the Scientific Research Project of Education Department of Hunan Province(No.21B000)and the Fundamental Research Funds for the Central Universities of Central South University.
文摘Accelerated industrialization combined with over-applied nitrogen fertilizers results in serious nitrate pollution insurface and ground water,disrupting the balance of the global nitrogen cycle.Electrochemical nitrate reduction(eNO_(3)RR)emerges as an attractive strategy to simultaneously enable nitrate removal and decentralized ammo-nia fabrication,restoring the globally perturbed nitrogen cycle.However,complex deoxygenation-hydrogenationprocesses and sluggish proton-electron transfer kinetics significantly hinder practical application of eNO_(3)RR.In this study,we developed carbon-coated Cu-Ni bimetallic catalysts derived from metal-organic frameworks(MOFs)to facilitate eNO_(3)RR.The unique structural features of catalyst promote enhanced synergy between Cuand Ni,effectively addressing critical challenges in nitrate reduction.Comprehensive structural and electrochem-ical analysis demonstrate that electrochemical nitrate-to-nitrite conversion mainly takes place on active Cu sites,the introduction of Ni could efficiently accelerate the generation of aquatic active hydrogen,promoting the hy-drogenation of oxynitrides during eNO_(3)RR.In addition,Ni introduction could push up the d-band center of thecatalyst,thus enhancing the adsorption and activation of nitrate and the corresponding intermediates.Detailedreaction pathways for nitrate-to-ammonia conversion are illuminated by rotating disk electrode(RDE),in-situFourier-transform infrared spectroscopy,in-situ Raman spectrum and electrochemical impedance spectroscopy(EIS).Benefiting from the synergistic effect of Cu and Ni,optimum catalyst exhibited excellent nitrate reductionperformance.This work provides a new idea for elucidating the underlying eNO_(3)RR reaction mechanisms andcontributes a promising strategy for designing efficient bimetallic electrocatalysts.
基金supported by the National Key Research and Development Project(No.2020YFA0907500)the National Natural Science Foundation of China(No.22476206)+1 种基金the supports from the National Young Top-Notch Talents(No.W03070030)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202011).
文摘Fe reducing bacteria(FRB),through extracellular electron transfer(EET)pathway,can reduce Fe(III)nanoparticles,thereby affecting the migration,transformation,and degradation of pollutants.However,the interaction of Fe(III)nanoparticles with the most commonly identified FRB,Geobacter sulfurreducens PCA,remains poorly understood.Herein,we demonstrated that the synergistic role of outer membrane proteins and periplasmic proteins in the EET process for-Fe_(2)O_(3),Fe3O4,and𝛽α-FeOOH nanoparticles by construction of multiple gene knockout strain.oxpG(involved in the type II secretion system)and omcST(outer membrane c-type cytochrome)medi-ated pathways accounted for approximately 67%of the total reduction of𝛼α-Fe_(2)O_(3) nanoparticles.The residual reduction of𝛼α-Fe_(2)O_(3) nanoparticles in∆oxpG-omcST strain was likely caused by redox-active substances in cell supernatant.Conversely,the reduction of dissolved Fe(III)was almost unaffected in∆oxpG-omcST strain at the same concentration.However,at high dissolved Fe(III)concentration,the reduction significantly decreased due to the formation of Fe(III)nanoparticles,suggesting that this EET process is specific to Fe(III)nanoparticles.Overall,our study provided a more comprehensive understanding for the EET pathways between G.sulfurreducens PCA and different Fe(III)species,enriching our knowledge on the role of microorganisms in iron biogeochemical cycles and remediation strategies of pollutants.
基金supported by the National Natural Science Foundations of China (Grant Nos.12235007,12001424,12271324,and 12501333)the Natural Science Basic research program of Shaanxi Province (Grant Nos.2021JZ-21 and 2024JC-YBQN-0069)+3 种基金the China Postdoctoral Science Foundation (Grant Nos.2020M673332 and 2024M751921)the Fundamental Research Funds for the Central Universities (Grant No.GK202304028)the 2023 Shaanxi Province Postdoctoral Research Project (Grant No.2023BSHEDZZ186)Xi’an University,Xi’an Science and Technology Plan Wutongshu Technology Transfer Action Innovation Team(Grant No.25WTZD07)。
文摘This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solitons propagating against a Painlevé wave background,in analogy to the established notion of elliptic solitons,which refers to solitons on an elliptic wave background.By employing a novel symmetry decomposition method aided by nonlocal residual symmetries,we explicitly construct (extended) Painlevé Ⅱ solitons for the Korteweg-de Vries equation and (extended) Painlevé Ⅳ solitons for the Boussinesq equation.
基金supported by National Natural Science Foundation of China(Nos.52274343 and 52474370)the China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202102).
文摘It is an important way to realize low carbon in China’s iron and steel industry by hydrogen-rich blast furnace smelting process.Sinter is the main blast furnace burden,and its reduction characteristics have a significant influence on ironmaking.The reduction behaviors,including reduction index(RI)and low-temperature reduction disintegration index(RDI),and the reduction mechanism of sinter in hydrogen-rich blast furnace were investigated.The results show that RI increased from 82.85 to 95.53 wt.%with an increase in H_(2)content from 0 to 30 vol.%,and the main phase of the reduction product was metallic iron.In the research of RDI,when the H_(2)content was increased from 0 to 20 vol.%,RDI+3.15 increased from 69.61 to 75.38 wt.%,and the main reaction was the reduction of hematite to magnetite.At 600-950℃,the reduction of sinter in CO and hydrogen-rich atmospheres(H_(2):CO=2)was both controlled by the first-order reaction model,and the apparent activation energy was 33.64 and 44.57 kJ/mol,respectively.
基金supported by the National Key R&D Program of China(No.2021YFC2901200)National Natural Science Foundation of China(Nos.52174383 and 52374412)Liaoning Provincial Natural Science Foundation of China(No.2022-YQ-09).
文摘To recover the valuable elements in Bayan Obo tailings,Fe-Si bath smelting reduction was adopted to separate and enrich rare earth elements(REE),niobium and titanium from the REE-Nb-Ti-containing slag.The reduction reaction process of the Fe-Si bath and the migration behavior of valuable elements in the solidification and crystallization process of silicothermic reduction tailings were investigated,and a treatment method for efficiently separating and enriching REE,Nb and Ti was explored.Thermodynamic analysis indicated that at 1600℃,with a 6 wt.%addition of Si as the reducing agent,the niobium oxide in the REE-Nb-Ti-containing slag could be selectively reduced to metallic Nb.In the Fe-Si bath reduction process,the Nb mass fraction in the metal phase increased with prolonged reaction time,peaking at 2.77%,while the Ti mass fraction consistently stayed below 0.12%.Lowering the w(CaO)/w(SiO_(2))enhanced the migration of Nb from slag to metal phase and reduced the Ti impurities.During solidification and crystallization,a significant quantity of perovskite precipitated from reduction tailings,with the REE dissolving into this perovskite.By adjusting the w(CaO)/w(SiO_(2))in tailings to 1.2-1.9 and maintaining a temperature of 1100℃for 4 h,the perovskite area fraction in the final slag could exceed 37%.Finally,a method was proposed to separate and enrich valuable elements in REE-Nb-Ti-containing slags via Fe-Si bath smelting reduction and crystallization control.
基金supported by the National Natural Science Foundation of China(No.52474355)the Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project),China(Nos.2022JH25/10200003 and 2023JH2/101800058).
文摘The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large deformation during the LCR process and to minimize the thickness of the slab in bending segments,the maximum theoretical reduction amount and the corresponding reduction scheme for the LCR process must be determined.With SPA-H weathering steel as a specific research steel grade,the distributions of tem-perature and deformation fields of a slab with the LCR process were analyzed using a three-dimensional thermal-mechanical finite ele-ment model.High-temperature tensile tests were designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperatures,and a prediction model of the critical strain for two typical cracks,combining the effects of strain rate and temperature,was proposed by incorporating the Zener-Hollomon parameter.The crack risks with different LCR schemes were calculated using the crack risk prediction model,and the maximum theoretical reduction amount for the SPA-H slab with a transverse section of 145 mm×1600 mm was 41.8 mm,with corresponding reduction amounts for Segment 0 to Segment 4 of 15.8,7.3,6.5,6.4,and 5.8 mm,respectively.
基金supported by the National Natural Science Foundation of China(12205300(H.S.),12405377(M.H.L))the Postdoctoral Science Foundation of China(2024M763694(M.H.L))+3 种基金the Natural Science Foundation of Hunan Province(2024JJ4027(H.S.))the Postdoctoral Fellowship Program of CPSF under Grant Number GZB20240859(M.H.L)financial support from the Hunan Normal University Program(grant05311204666)financial support from the 2024 Large Instrument Testing Open Fund of Hunan Normal University(24CSY033,24CSY086)。
文摘The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path and the low reactive species(nitrate and proton)concentration at the catalyst interface inhibit the efficiency of ammonia production from nitrate reduction reaction(NitRR).Herein,we introduce a novel iron-based tandem catalyst encapsulated by reduced graphene oxide(denoted as Fe-rGO),with a superior ammonia production rate of 47.815 mg h^(-1)mg_(ca)^(t-1)and a high Faraday efficiency(FE)of 96.51%at an applied potential of-0.5 V.It also delivers a robust stability with FE above90%under a current density of 250 mA cm^(-2)for 50 h.In situ X-ray absorption spectroscopy reveals that the FeO_(x)is dynamically translated to Fe~0 site concurrently with the enhancement of the NH_(3)production rate,suggesting the Fe^(0) site as hydrogenation active center.The asymmetric distribution of surface charges of rGO not only enriches nitrate ions at the catalytic interface and promotes the hydrogenation process in NitRR,but also protects the iron species and ensures their stability during electrolysis.The Zn-NO_(3)^(-)battery demonstrates an impressive FE of 88.6%,highlighting its exceptional potential for practical applications.
基金Project(NCET-10-0834)supported by the Program for New Century Excellent Talents in University,China
文摘The solid-state reduction kinetics of pre-oxidized vanadium-titanium magnetite concentrate was studied. The phase and microstructure of the reduction product were characterized by XRD, SEM and EDS methods, based on which the mechanism of the solid-state reduction was investigated. The results showed that using coal as reductant at 950-1100 °C, the solid-state reduction of the pre-oxidized vanadium-titanium magnetite concentrate was controlled by interface chemical reaction and the apparent activation energy was 67.719 k J/mol. The mineral phase transformation during the reduction process can be described as follows： pre-oxidized vanadium-titanium magnetite concentrate → ulvospinel → ilmenite → Fe Ti2O5 →（FenTi1-n）Ti2O5. M3O5-type（M can be Fe, Ti, Mg, Mn, etc） solid solutions would be formed during the reduction process of the pre-oxidized vanadium-titanium magnetite concentrate at 1050 °C for 60 min. The poor reducibility of iron in M3O5 solid solutions is the main reason to limit the reduction property of pre-oxidized vanadium-titanium magnetite concentrate.
基金support from the National Natural Science Foundation of China(No.52174300)Natural Science Foundation of Chongqing,China(Nos.cstc2020jcyj-msxmX0583 and cstc2021jcyj-msxmX1004)+1 种基金Chongqing Talent Plan Project(No.cstc2021ycjh-bgzxm0211)Chongqing Doctoral"Through Train"Project(No.sl202100000343).T。
文摘Iron ore pellets,as one of the main charges of blast furnaces,have a greater impact on the CO_(2)emission reduction and stable operation of blast furnaces.The isothermal reduction behavior of the pellets obtained from a Chinese steel plant was studied in the gas mixtures of CO and N_(2).The results showed the reduction process is divided into two stages.The reduction in the initial stage(time t≤40 min)is cooperatively controlled by internal diffusion and interface chemical reactions with the activation energy of 30.19 and 16.67 kJ/mol,respectively.The controlling step of the reduction in the final stage(t>40 min)is internal diffusion with the activation energy of 34.60 kJ/mol.The reduction process can be described by two equations obtained from kinetic calculations.The reduction degree can be predicted under different temperatures and time,and the predicted results showed an excellent correlation with the experimental results.The reduction mechanisms were confirmed by the analysis of the scanning electron microscope equipped with an energy dispersive spectrometer and optical microscope.
基金Supported by National Natural Science Foundation of China(Grant Nos.52405001,52175001,62373010,82472537)China Postdoctoral Science Foundation(Grant No.2024M760166)+2 种基金Postdoctoral Fellowship Program of CPSF(Grant No.GZC20230186)Shenzhen Municipal Science,Technology,and Innovation Commission(Grant No.SGDX20220530111005036)Beijing Natural Science Foundation(Grant Nos.3222002,3232004,L222061).
文摘Long-bone fractures are common complaints in orthopedic surgery.In recent years,significant progress has been made in robot-assisted fracture-reduction techniques.As a key medical device for diverse fracture morphologies and sites,the design of the reduction robot has a profound impact on the reduction outcomes.However,existing reduction robots have practical limitations and cannot simultaneously satisfy clinical requirements in terms of workspace,force/torque,and structural stiffness.To overcome these problems,we first analyze the potential placement areas and performance requirements of reduction robots according to clinical application scenarios.Subsequently,a 3UPS/S-3P hybrid configuration with decoupled rotational and translational degrees of freedom(DOFs)is proposed,and a kinematic model is derived to achieve the motion characteristics of the remote center of motion(RCM).Furthermore,the structural design of a hybrid reduction robot with an integrated distal clamp and proximal fixator was completed,and a mechanical prototype was constructed.The results of the performance evaluations and static analysis demonstrate that the proposed reduction robot has acceptable workspace,force,and torque performance and excellent structural stiffness.Two clinical case simulations further demonstrated the clinical feasibility of the robot.Finally,preliminary experiments on bone models demonstrated the potential effectiveness of the proposed reduction robot in lower-limb fracture reduction.
文摘Electrochemical nitrate reduction(eNO_(3)RR)and nitric oxide reduction(eNORR)to ammonia have emerged as promising and sustainable alternatives to the traditional Haber-Bosch method for ammonia production,particularly within the recently proposed reverse artificial nitrogen cycle route:N_(2)→NO_(x)→NH_(3).Notably,experimental studies have demonstrated that eNORR exhibits superior performance over eNO_(3)RR on Cu6Sn5 catalysts.However,the fundamental mechanisms underlying this difference remain poorly understood.Herein,we performed systematic theoretical calculations to explore the reaction pathways,electronic structure effects,and potential-dependent Faradic efficiency associated with ammonia production via these two distinct electrochemical pathways(eNORR and eNO_(3)RR)on Cu6Sn5.By implementing an advanced‘adaptive electric field controlled constant potential(EFC-CP)’methodology combined with microkinetic modeling,we successfully reproduced the experimental observations and identified the key factors affecting ammonia production in both reaction pathways.It was found that eNORR outperforms eNO_(3)RR because it circumvents the ^(*)NO_(2) dissociation and ^(*)NO_(2) desorption steps,leading to distinct surface coverage of key intermediates between the two pathways.Furthermore,the reaction rates were found to exhibit a pronounced dependence on the surface coverage of ^(*)NO in eNORR and ^(*)NO_(2) in eNO_(3)RR.Specifically,the facile desorption of ^(*)NO_(2) on the Cu6Sn5 surface in eNO_(3)RR limits the attainable surface coverage of ^(*)NO,thereby impeding its performance.In contrast,the eNORR can maintain a high surface coverage of adsorbed ^(*)NO species,contributing to its enhanced ammonia production performance.These fundamental insights provide valuable guidance for the rational design of catalysts and the optimization of reaction routes,facilitating the development of more efficient,sustainable,and scalable techniques for ammonia production.
基金support from the National Natural Science Foundation of China(52174290).
文摘To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that the MgO addition decreased the reduction swelling index(RSI)and reduction degree of pellets in both CO and H_(2)atmospheres.During the stepwise reduction process of Fe2O3→Fe3O4→FeO,the reduction behaviour of pellets in CO and H_(2)was similar,while the reduction rate of pellets in H_(2)atmosphere was almost twice as high as that in CO atmosphere.During the stepwise reduction process of FeO→Fe,the RSI of pellets showed a logarithmic increase in CO atmosphere and a linear decrease in H_(2)atmosphere.As investigated by first-principles calculations,C and Fe mainly formed chemical bonds,and the CO reduction process released energy,promoting the formation of iron whiskers.However,H and Fe produced weak physical adsorption,and the H_(2)reduction process was endothermic,inhibiting the generation of iron whiskers.With Mg2+doping in FexO,the nucleation region of iron whiskers expanded in CO reduction process,and the morphology of iron whiskers transformed from“slender”to“stocky,”reducing RSI of the pellets.
基金This work was financially supported by the Hunan Province Key Research and Development Project(2023SK2079)and“Xiaohe”Young Talent Innovation Project in Changsha in 2023.
文摘Microwave pre-oxidation and biomass reduction were adopted to enhance the separation of titanium and iron in vanadium-titanium magnetite.The effects of microwave pre-oxidation temperature and time,as well as biomass reduction temperature and time,were investigated.The results showed that the average particle size of vanadium-titanium magnetite decreased,and the specific surface area increased with the increase in pre-oxidation temperature and time.The reaction pathway(Fe_(3-x)TixO_(4)→Fe_(2-x)TixO_(3)→Fe_(2)TiO_(5))was proved in microwave pre-oxidation process.The results of biomass reduction roasting showed that biomass reduction could effectively reduce ferric oxide to metallic iron while Ti was enriched in a solid solution of magnesium anosovite,which was beneficial to the subsequent grinding and acid leaching separation.The combined process of microwave pre-oxidation and biomass reduction achieved a high separation efficiency of titanium and iron in vanadium-titanium magnetite without forming complex titanium minerals.The titanium grade in the vanadium-titanium-rich material was 32.10%,and the recovery rate was 91.51%.The iron grade in the iron concentrate(metallic iron)was 90.90%,the recovery rate was 93.47%,and metallization rate was 93.87%.
