The hydrogen-based reduction and electric smelting technology is a green and low-carbon process for treating low-grade ore and complex symbiotic iron ore.In this study,the hydrogen-based reduction of boron-bearing iro...The hydrogen-based reduction and electric smelting technology is a green and low-carbon process for treating low-grade ore and complex symbiotic iron ore.In this study,the hydrogen-based reduction of boron-bearing iron concentrate and the low-temperature separation compared with the high-temperature melting separation of slag and iron from a boron-bearing iron concentrate were studied.The metallization rate of the boron-bearing iron concentrate reached 99.63%after hydrogen-based reduction at 1050℃,and the metallic iron was interwoven with olivine(Mg_(2)SiO_(4))in the reduced ore.In addition,the high-temperature melting separation of iron and slag could be accomplished at 1550℃for 60 min,where boron was mainly distributed in the form of a glass phase in the slag with a mass fraction of B_(2)O_(3)of 22.69%,and 0.35%of boron(mass fraction)was melted into liquid iron.By contrast,iron and slag were efficiently separated at a lower temperature(1300℃)for 10 min and enhanced by super-gravity.Almost all the boron content was enriched into a suanite phase in the slag with a considerably high mass fraction of B_(2)O_(3)(35.61%)and a high recovery ratio(99.37%),and the mass fraction of boron decreased to 0.15%in iron.Compared with high-temperature melting separation,low-temperature separation combined with hydrogen-based reduction greatly improved the enrichment of boron in slag and prevented the melting of boron into iron.展开更多
The steel industry’s transition to hydrogen-based ironmaking necessitates a deeper understanding of magnetite ore reduction,a crucial yet underexplored pathway for decarbonization.This study systematically investigat...The steel industry’s transition to hydrogen-based ironmaking necessitates a deeper understanding of magnetite ore reduction,a crucial yet underexplored pathway for decarbonization.This study systematically investigates the combined effects of particle size and gangue composition on hydrogen-based reduction behavior of four industrial magnetite ore concentrates with varying CaO and MgO con-tents.Thermogravimetric analysis at 973 K,interrupted reduction experiments,and post-reduction characterization steps are used to eval-uate reduction extent and phase transformations across different particle size fractions and bulk ores.The finer fractions generally exhibit faster and more complete reduction.However,this trend is overridden by gangue effects in certain ores.Magnetite ores with MgO as gangue tend to form magnesio-wustite solid solution(Mg,Fe)O during reduction,resulting in dense microstructures that impede hydrogen diffusion and limit reduction progress.In contrast,magnetite ores with CaO as gangue facilitate the formation of intermediate calcium fer-rites,which promote porous morphology and enhanced reducibility.Notably,even the finer particles of ore containing MgO show a lower reduction degree than the coarser particles of the ore containing CaO as gangue.This highlights the dominant role of gangue composition in governing reduction kinetics,intermediate phase formation and final product morphology.These findings contribute to the growing knowledge necessary to enable fossil-free ironmaking by emphasizing the importance of considering both granulometric characteristics and heterogeneity when evaluating magnetite ores for hydrogen-based reduction.展开更多
Iron tailings are a common solid waste resource,posing serious environmental and spatial challenges.This study proposed a novel hydrogen-based reduction roasting(HRR)technology for the processing of iron tailings usin...Iron tailings are a common solid waste resource,posing serious environmental and spatial challenges.This study proposed a novel hydrogen-based reduction roasting(HRR)technology for the processing of iron tailings using a combined beneficiation and metallurgy approach.Pilot-cale experiment results indicated that under the gas composition of CO:H_(2)=1:3,and optimal roasting conditions at a reduction temperature of 520℃,the majority of weakly magnetic hematite transforms into strongly magnetic magnetite during the reduction process.Combining roasting products with a magnetic separation-grinding-magnetic selection process yields a final iron concentrate with a grade of 56.68%iron and a recovery rate of 86.54%.Theoretical calculations suggested the annual production value can reach 29.7 million USD and a reduction of 20.79 tons of CO_(2) emissions per year.This highlights that the use of HRR in conjunction with traditional beneficiation processes can effectively achieve comprehensive utilization of iron tailings,thereby reducing environmental impact.展开更多
The novel process of hydrogen-based shaft furnaces(HSFs)has attracted considerable attention because of their significant reduction of CO_(2)emissions.In this study,the interaction of H_(2)and CO with Fe_(tet1)-and Fe...The novel process of hydrogen-based shaft furnaces(HSFs)has attracted considerable attention because of their significant reduction of CO_(2)emissions.In this study,the interaction of H_(2)and CO with Fe_(tet1)-and Fe_(oct2)-terminated Fe_(3)O_(4)(111)surfaces under HSF conditions,including their adsorption and reduction behaviors,was investigated using the density functional theory method.The results indicated that the H_(2)molecule adsorbed onto the Fe_(tet1)-terminated surface with an adsorption energy(AE)of-1.36 eV,whereas the CO molecule preferentially adsorbed on the Fe_(oct2)-terminated surface with an AE of-1.56 eV.Both H_(2)and CO can readily undergo reduction on the Fe_(tet1)-terminated surface(corresponding to energy barriers of 0.83 eV and 2.23 eV,respectively),but kinetically the reaction of H2is more favorable than that of CO.With regard to the thermodynamics at 400-1400 K,the H_(2)was easy to be adsorbed,while the CO would like to react on the Fe_(tet1)-terminated surface.These thermodynamically tendencies were reversed on the Fe_(oct2)-terminated surface.The thermodynamic disadvantage of the reaction of H_(2)on the Fe_(tet1)-terminated surface was offset by an increase in the temperature.Furthermore,the adsorption of H2 and CO on the Fe_(tet1)-terminated surface was competitive,whereas the adsorption of them on the Fe_(oct2)-terminated surface was synergistic.Therefore,iron ores with a higher proportion of Fe_(tet1)-terminated surface can be applied for the HSF process.In conjunction with the increases in the reduction temperature and the ratio of H_(2)in the reducing gas would promote efficient HSF smelting.These observations provide effective guidance for optimizing the practical operation parameters and advancing the development of the HSF process.展开更多
The sticking behavior of pellets affects the continuity of production in hydrogen-based shaft furnace.The coupling influences of V_(2)O_(5) and reduction temperature on reduction sticking behavior and mechanism evolut...The sticking behavior of pellets affects the continuity of production in hydrogen-based shaft furnace.The coupling influences of V_(2)O_(5) and reduction temperature on reduction sticking behavior and mechanism evolution of pellets under hydrogen atmosphere are investigated.The increase in V_(2)O_(5) addition aggravated the reduction sticking behavior,which is attributed to the combined functions of the development of unique interwoven structure in the metallic iron interconnections at the reduction sticking interface and the deterioration of reduction swelling behavior of pellets.In addition,the strength of metallic iron interconnections enhanced and reduction sticking behavior aggravated with the increase in reduction temperature.Importantly,compared to other reduction temperatures,the reduction sticking behavior of pellets was most significantly aggravated with the increase in V_(2)O_(5) addition at 1000℃.And the values of sticking index increased from 10.22%to 15.36% as the V_(2)O_(5) addition increased from 0 to 1.00 wt.%at 1000℃.展开更多
In order to explore the reduction pathways of zinc oxide in LiCl molten salt and the optimal process,experiments were conducted in an alumina crucible using metallic lithium as the reducing agent and lithium chloride ...In order to explore the reduction pathways of zinc oxide in LiCl molten salt and the optimal process,experiments were conducted in an alumina crucible using metallic lithium as the reducing agent and lithium chloride molten salt as the reaction medium at 923 K.The study assessed the effects of lithium thermochemical reduction and electrolytic reduction of ZnO.The volatilization behavior of metal oxides in molten salts,the equivalent of a reducing agent,reduction time,amount of molten salt,stirring time,and the method of reduction feed were investigated for their impacts on the reduction yield and product composition.X-ray powder diffraction(XRD)analysis of the products showed that lithium reduction of ZnO not only produced metallic Zn but also formed a LiZn alloy.Electrolytic reduction can be used to obtain the metallic Zn product by controlling the potential below-2.2 V(vs Ag/Ag^(+)).Moreover,sintered oxides and higher electrode potentials could enhance the efficiency of electrolysis.Under the optimal reaction conditions determined experimentally,the lithium reduction experiment achieved a yield of 77.2%after a 12-h test,and the electrolytic reduction reached a yield of 85.4%after a 6-h test.展开更多
This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the correspo...This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4.展开更多
Experts and officials shared their insights on poverty reduction cooperation and sustainable development during the 2025 International Seminar on Global Poverty Reduction Partnerships.
The recycling of neptunium(Np)from nuclear wastes is crucial for the sustainable development of nuclear energy,yet it is still a challenging task owing to the complexity of Np chemistry.Precise control of oxidation st...The recycling of neptunium(Np)from nuclear wastes is crucial for the sustainable development of nuclear energy,yet it is still a challenging task owing to the complexity of Np chemistry.Precise control of oxidation state is highly desirable for the effective recovery of Np.In this study,we report an innovative strategy for Np recovery through in-situ coordination and reduction of Np(Ⅴ)in a biphasic extraction system.By leveraging the synergistic effects of coordination by a P=O donating ligand(trialkyl phosphine oxide,TRPO)and reduction by hydroquinone(HQ)in the organic phase,efficient Np(Ⅴ)-to-Np(Ⅳ)conversion and high distribution ratio(D)of Np were achieved in a single extraction contact.The reduction mechanism of Np was elucidated through spectroscopic and theoretical analyses.This work enriches the redox chemistry of Np and provides a novel pathway for Np recovery in advanced nuclear fuel cycles.展开更多
In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry bet...In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH3 partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.展开更多
The demand for ^(238)Pu(nuclear battery heat source)drives the separation of its precursor,^(237)Np,from spent nuclear fuel(SNF).However,the co-existence of multi-valence states(IV/V/VI)of Np and similar redox behavio...The demand for ^(238)Pu(nuclear battery heat source)drives the separation of its precursor,^(237)Np,from spent nuclear fuel(SNF).However,the co-existence of multi-valence states(IV/V/VI)of Np and similar redox behavior with Pu(IV)hinder the effective separation of Np.N-Butyraldehyde(n-C_(3)H_(7)CHO)selectively reduces Np(VI)to Np(V)without reducing Pu(IV).Herein,we examined the reduction mechanisms of Np(VI)and Pu(IV)by n-C_(3)H_(7)CHO using relativistic density functional theory.Based on the results of the potential energy profiles,the reductions of both Np(VI)and Pu(IV)by n-C_(3)H_(7)CHO are thermodynamically feasible,whereas only the former is kinetically achievable.It uncovers that n-C_(3)H_(7)CHO can only reduce Np(VI)to Np(V)owing to kinetically controlled selective reduction.The analyses of spin density and bond distance indicate that the reduction nature for the first Np(VI)/Pu(IV)belongs to hydrogen atom transfer,whereas that for the second one involves outer-sphere electron transfer.Localized molecular orbitals(LMOs)analysis discloses the bonding evolution during the reduction process of Np(VI)/Pu(IV).This study elucidates the reason behind the kinetically controlled selective reduction of Np(VI)/Pu(IV)by n-C_(3)H_(7)CHO at the molecular level and offers in-depth perspectives on the isolation of specific metal ions from the view of kinetic control.展开更多
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
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
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
Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural ga...Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural gases.We used the GC-Py-GC-IRMS method to study TSR and obtained a novel finding related to intramolecular carbon isotope fractionation in natural propane.The results show that theΔC-T(δ^(13)C_(central)-13 C_(terminal))andδ^(13)C_(central)values significantly increased to 44.7‰and 11.9‰,respectively,with increasing TSR alteration.In contrast,the 13 C_(terminal)values of propane remained largely unaltered by the TSR reaction.This difference in position-specific isotope fractionation can be attributed to the central carbon’s reactivity being higher than that of terminal carbon during TSR.In sum,the results indicate that theδ^(13)C_(terminal)values of propane can serve as robust indicators for source rock identification of natural gas altered by post-generation reactions such as TSR and anaerobic microbial oxidation.展开更多
The hydrogen reduction kinetics of tungsten trioxide(WO_(3))was investigated via non-isothermal thermogravimetric analysis.Under the local gas-solid reduction conditions,the particle morphology of tungsten powders was...The hydrogen reduction kinetics of tungsten trioxide(WO_(3))was investigated via non-isothermal thermogravimetric analysis.Under the local gas-solid reduction conditions,the particle morphology of tungsten powders was found to be consistent with that of raw material WO_(3).The removal of oxygen from tungsten oxide during hydrogen reduction led to the formation of porous structures between the reduced particles,which were obviously different from the polyhedral single-crystal configuration of tungsten powders obtained via chemical vapor deposition.Moreover,the two-stage hydrogen reduction mechanisms of WO_(3) under the local gas-solid reduction conditions can be described using the composite autocatalytic function.The activation energies of the first and second stages of the hydrogen reduction of WO_(3) were determined to be 121 and 135 kJ/mol,respectively.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
Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchan...Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.展开更多
The rapid recombination of photogenerated charge carriers and the poor stability of metal sulfides remain bottlenecks limiting their practical applications. In this study, sulfur vacancies were introduced into an S-sc...The rapid recombination of photogenerated charge carriers and the poor stability of metal sulfides remain bottlenecks limiting their practical applications. In this study, sulfur vacancies were introduced into an S-scheme AgIn_(5)S_(8)/Bi_(2)S_(3) heterojunction via an in situ hydrothermal method. The sulfur vacancies induced charge density redistribution within the heterojunction and generated efficient active sites for electrons, thereby creating a localized electron-rich environment. The synergistic effects of the sulfur vacancies, internal electric field, and defect energy levels accelerated the separation and transfer of photogenerated charge carriers via the S-scheme pathway, thereby enhancing the visible-light photocatalytic performance, by achieving a Cr(Ⅵ) reduction efficiency of 99.6%. More importantly, the long-term stability and excellent anti-interference capability of the S-scheme AgIn_(5)S_(8)/Bi_(2)S_(3) heterojunction demonstrate its practical application potential, achieving 98.9% Cr(Ⅵ) removal from real electroplating wastewater and meeting discharge standards. This work provides a theoretical basis for constructing highly-catalytic S-scheme heterojunctions and serves as a promising solution for Cr(VI)-containing electroplating wastewater treatment.展开更多
Exploring high-performance electrocatalysts for the nitrate reduction reaction(NO_(3)RR)is crucial for environmental nitrate removal and ammonia synthesis.Single-atom collaboration with cluster can provide sufficient ...Exploring high-performance electrocatalysts for the nitrate reduction reaction(NO_(3)RR)is crucial for environmental nitrate removal and ammonia synthesis.Single-atom collaboration with cluster can provide sufficient active sites for catalysts to promote NO_(3)RR,yet the unclear synergistic effect between the two hinders their rational design.Herein,a series of Ir_(3)clusters and metal single atoms co-embedded in graphitic carbon nitride(g-CN)catalysts(Ir_(3)M1)were constructed,and the synergistic effects of Ir_(3)clusters and M1 single atoms on the NO_(3)RR catalytic mechanism and activity were systematically explored using density functional theory(DFT)calculations combined with machine learning.Comprehensive evaluations of structural stability and catalytic activity demonstrate that the synergy between single atoms and clusters effectively balances the adsorption energies of key intermediates,yielding exceptional catalytic performance(the limiting potential of Ir_(3)Ti_(1)can reach−0.22 V).Machine learning models further clarify the synergistic mechanism,where the geometric configurations of clusters serve as critical features for modulating the catalytic activity of single-atom sites,whereas the electronic structures of single atoms directly govern the reactivity of cluster sites.This DFT-machine learning approach provides theoretical guidelines for catalyst design and a predictive framework for efficient NO_(3)RR electrocatalysts.展开更多
文摘The hydrogen-based reduction and electric smelting technology is a green and low-carbon process for treating low-grade ore and complex symbiotic iron ore.In this study,the hydrogen-based reduction of boron-bearing iron concentrate and the low-temperature separation compared with the high-temperature melting separation of slag and iron from a boron-bearing iron concentrate were studied.The metallization rate of the boron-bearing iron concentrate reached 99.63%after hydrogen-based reduction at 1050℃,and the metallic iron was interwoven with olivine(Mg_(2)SiO_(4))in the reduced ore.In addition,the high-temperature melting separation of iron and slag could be accomplished at 1550℃for 60 min,where boron was mainly distributed in the form of a glass phase in the slag with a mass fraction of B_(2)O_(3)of 22.69%,and 0.35%of boron(mass fraction)was melted into liquid iron.By contrast,iron and slag were efficiently separated at a lower temperature(1300℃)for 10 min and enhanced by super-gravity.Almost all the boron content was enriched into a suanite phase in the slag with a considerably high mass fraction of B_(2)O_(3)(35.61%)and a high recovery ratio(99.37%),and the mass fraction of boron decreased to 0.15%in iron.Compared with high-temperature melting separation,low-temperature separation combined with hydrogen-based reduction greatly improved the enrichment of boron in slag and prevented the melting of boron into iron.
文摘The steel industry’s transition to hydrogen-based ironmaking necessitates a deeper understanding of magnetite ore reduction,a crucial yet underexplored pathway for decarbonization.This study systematically investigates the combined effects of particle size and gangue composition on hydrogen-based reduction behavior of four industrial magnetite ore concentrates with varying CaO and MgO con-tents.Thermogravimetric analysis at 973 K,interrupted reduction experiments,and post-reduction characterization steps are used to eval-uate reduction extent and phase transformations across different particle size fractions and bulk ores.The finer fractions generally exhibit faster and more complete reduction.However,this trend is overridden by gangue effects in certain ores.Magnetite ores with MgO as gangue tend to form magnesio-wustite solid solution(Mg,Fe)O during reduction,resulting in dense microstructures that impede hydrogen diffusion and limit reduction progress.In contrast,magnetite ores with CaO as gangue facilitate the formation of intermediate calcium fer-rites,which promote porous morphology and enhanced reducibility.Notably,even the finer particles of ore containing MgO show a lower reduction degree than the coarser particles of the ore containing CaO as gangue.This highlights the dominant role of gangue composition in governing reduction kinetics,intermediate phase formation and final product morphology.These findings contribute to the growing knowledge necessary to enable fossil-free ironmaking by emphasizing the importance of considering both granulometric characteristics and heterogeneity when evaluating magnetite ores for hydrogen-based reduction.
基金National Natural Science Foundation of China(52104249)Liaoning Joint Fund General Support Program Project(2023-MSBA-126)the Fundamental Research Funds for the Central Universities(N2401019).
文摘Iron tailings are a common solid waste resource,posing serious environmental and spatial challenges.This study proposed a novel hydrogen-based reduction roasting(HRR)technology for the processing of iron tailings using a combined beneficiation and metallurgy approach.Pilot-cale experiment results indicated that under the gas composition of CO:H_(2)=1:3,and optimal roasting conditions at a reduction temperature of 520℃,the majority of weakly magnetic hematite transforms into strongly magnetic magnetite during the reduction process.Combining roasting products with a magnetic separation-grinding-magnetic selection process yields a final iron concentrate with a grade of 56.68%iron and a recovery rate of 86.54%.Theoretical calculations suggested the annual production value can reach 29.7 million USD and a reduction of 20.79 tons of CO_(2) emissions per year.This highlights that the use of HRR in conjunction with traditional beneficiation processes can effectively achieve comprehensive utilization of iron tailings,thereby reducing environmental impact.
基金financially supported by the Key Program of National Natural Science Foundation of China(No.U23A20608)the Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project),China(No.2023JH2/101800058)+3 种基金the Science&Technology Plan Project of Hebei Province,China(No.23314601L)the Project of Hydrogen-Based Shaft Furnace Reduction-Electric Furnace Melting And Separation Technology Research and Application for High-Titanium Magnetite Iron Ore(No.HG2023239)the General Program of National Natural Science Foundation of China(No.52274253)the Special Project for Major Scientific and Technological Achievements Transformation in Hebei Province,China(No.23284101Z)。
文摘The novel process of hydrogen-based shaft furnaces(HSFs)has attracted considerable attention because of their significant reduction of CO_(2)emissions.In this study,the interaction of H_(2)and CO with Fe_(tet1)-and Fe_(oct2)-terminated Fe_(3)O_(4)(111)surfaces under HSF conditions,including their adsorption and reduction behaviors,was investigated using the density functional theory method.The results indicated that the H_(2)molecule adsorbed onto the Fe_(tet1)-terminated surface with an adsorption energy(AE)of-1.36 eV,whereas the CO molecule preferentially adsorbed on the Fe_(oct2)-terminated surface with an AE of-1.56 eV.Both H_(2)and CO can readily undergo reduction on the Fe_(tet1)-terminated surface(corresponding to energy barriers of 0.83 eV and 2.23 eV,respectively),but kinetically the reaction of H2is more favorable than that of CO.With regard to the thermodynamics at 400-1400 K,the H_(2)was easy to be adsorbed,while the CO would like to react on the Fe_(tet1)-terminated surface.These thermodynamically tendencies were reversed on the Fe_(oct2)-terminated surface.The thermodynamic disadvantage of the reaction of H_(2)on the Fe_(tet1)-terminated surface was offset by an increase in the temperature.Furthermore,the adsorption of H2 and CO on the Fe_(tet1)-terminated surface was competitive,whereas the adsorption of them on the Fe_(oct2)-terminated surface was synergistic.Therefore,iron ores with a higher proportion of Fe_(tet1)-terminated surface can be applied for the HSF process.In conjunction with the increases in the reduction temperature and the ratio of H_(2)in the reducing gas would promote efficient HSF smelting.These observations provide effective guidance for optimizing the practical operation parameters and advancing the development of the HSF process.
基金supported by the authors are especially grateful to the National Natural Science Foundation of China(Grant No.51904063)the Key Program of National Natural Science Foundation of China(No.U23A20608)+6 种基金Fundamental Research Funds for the Central Universities(N2025023,N2225046)Postdoctoral Followship Program of CPSF(GZC20230392)Science&Technology Plan Project of Liaoning Province(2022JH24/10200027)Science&Technology Plan Project of Hebei Province(23314601L)Science and Technology Program of Liaoning of China(2023JH2/101700304)China Postdoctoral Science Foundation(2023M740551)Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project)(2023JH2/101800058).
文摘The sticking behavior of pellets affects the continuity of production in hydrogen-based shaft furnace.The coupling influences of V_(2)O_(5) and reduction temperature on reduction sticking behavior and mechanism evolution of pellets under hydrogen atmosphere are investigated.The increase in V_(2)O_(5) addition aggravated the reduction sticking behavior,which is attributed to the combined functions of the development of unique interwoven structure in the metallic iron interconnections at the reduction sticking interface and the deterioration of reduction swelling behavior of pellets.In addition,the strength of metallic iron interconnections enhanced and reduction sticking behavior aggravated with the increase in reduction temperature.Importantly,compared to other reduction temperatures,the reduction sticking behavior of pellets was most significantly aggravated with the increase in V_(2)O_(5) addition at 1000℃.And the values of sticking index increased from 10.22%to 15.36% as the V_(2)O_(5) addition increased from 0 to 1.00 wt.%at 1000℃.
文摘In order to explore the reduction pathways of zinc oxide in LiCl molten salt and the optimal process,experiments were conducted in an alumina crucible using metallic lithium as the reducing agent and lithium chloride molten salt as the reaction medium at 923 K.The study assessed the effects of lithium thermochemical reduction and electrolytic reduction of ZnO.The volatilization behavior of metal oxides in molten salts,the equivalent of a reducing agent,reduction time,amount of molten salt,stirring time,and the method of reduction feed were investigated for their impacts on the reduction yield and product composition.X-ray powder diffraction(XRD)analysis of the products showed that lithium reduction of ZnO not only produced metallic Zn but also formed a LiZn alloy.Electrolytic reduction can be used to obtain the metallic Zn product by controlling the potential below-2.2 V(vs Ag/Ag^(+)).Moreover,sintered oxides and higher electrode potentials could enhance the efficiency of electrolysis.Under the optimal reaction conditions determined experimentally,the lithium reduction experiment achieved a yield of 77.2%after a 12-h test,and the electrolytic reduction reached a yield of 85.4%after a 6-h test.
文摘This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4.
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the financial support from the National Natural Science Foundation of China(22325603)the financial support from the National Natural Science Foundation of China(22376116)+3 种基金the financial support from the National Natural Science Foundation of China(22076130)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST)(2023QNRC001)the Fundamental Research Funds for the Central Universities(20826041D4117)the Natural Science Foundation of Sichuan(2025ZNSFSC0109)。
文摘The recycling of neptunium(Np)from nuclear wastes is crucial for the sustainable development of nuclear energy,yet it is still a challenging task owing to the complexity of Np chemistry.Precise control of oxidation state is highly desirable for the effective recovery of Np.In this study,we report an innovative strategy for Np recovery through in-situ coordination and reduction of Np(Ⅴ)in a biphasic extraction system.By leveraging the synergistic effects of coordination by a P=O donating ligand(trialkyl phosphine oxide,TRPO)and reduction by hydroquinone(HQ)in the organic phase,efficient Np(Ⅴ)-to-Np(Ⅳ)conversion and high distribution ratio(D)of Np were achieved in a single extraction contact.The reduction mechanism of Np was elucidated through spectroscopic and theoretical analyses.This work enriches the redox chemistry of Np and provides a novel pathway for Np recovery in advanced nuclear fuel cycles.
基金supported by the Natural Science Foundation(NSF)of China(Nos.22205015,22175020,and 22235001)the National Postdoctoral Program for Innovative Talents(No.BX20220032)+2 种基金the China Postdoctoral Science Foundation Funded Project(No.2022BG013)the Fundamental Research Funds for the Central Universities(Nos.00007709,00007770,and FRFBR-23-02B)University of Science and Technology Beijing is gratefully acknowledged.
文摘In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH3 partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.
基金supported by the National Natural Science Foundation of China(Nos.22376197,U2441225,22076188).
文摘The demand for ^(238)Pu(nuclear battery heat source)drives the separation of its precursor,^(237)Np,from spent nuclear fuel(SNF).However,the co-existence of multi-valence states(IV/V/VI)of Np and similar redox behavior with Pu(IV)hinder the effective separation of Np.N-Butyraldehyde(n-C_(3)H_(7)CHO)selectively reduces Np(VI)to Np(V)without reducing Pu(IV).Herein,we examined the reduction mechanisms of Np(VI)and Pu(IV)by n-C_(3)H_(7)CHO using relativistic density functional theory.Based on the results of the potential energy profiles,the reductions of both Np(VI)and Pu(IV)by n-C_(3)H_(7)CHO are thermodynamically feasible,whereas only the former is kinetically achievable.It uncovers that n-C_(3)H_(7)CHO can only reduce Np(VI)to Np(V)owing to kinetically controlled selective reduction.The analyses of spin density and bond distance indicate that the reduction nature for the first Np(VI)/Pu(IV)belongs to hydrogen atom transfer,whereas that for the second one involves outer-sphere electron transfer.Localized molecular orbitals(LMOs)analysis discloses the bonding evolution during the reduction process of Np(VI)/Pu(IV).This study elucidates the reason behind the kinetically controlled selective reduction of Np(VI)/Pu(IV)by n-C_(3)H_(7)CHO at the molecular level and offers in-depth perspectives on the isolation of specific metal ions from the view of kinetic control.
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supported by the Helium Enrichment and Detection in Natural Gas Reservoirs Related to Oil and Gas Fields project(Grant No.2025ZD1010500)the Deep Earth Probe and Mineral Resources Exploration―National Science and Technology Major Project.-。
文摘Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural gases.We used the GC-Py-GC-IRMS method to study TSR and obtained a novel finding related to intramolecular carbon isotope fractionation in natural propane.The results show that theΔC-T(δ^(13)C_(central)-13 C_(terminal))andδ^(13)C_(central)values significantly increased to 44.7‰and 11.9‰,respectively,with increasing TSR alteration.In contrast,the 13 C_(terminal)values of propane remained largely unaltered by the TSR reaction.This difference in position-specific isotope fractionation can be attributed to the central carbon’s reactivity being higher than that of terminal carbon during TSR.In sum,the results indicate that theδ^(13)C_(terminal)values of propane can serve as robust indicators for source rock identification of natural gas altered by post-generation reactions such as TSR and anaerobic microbial oxidation.
基金supported by the National Key Research&Development Program of China(No.2022YFC2904905)the National Natural Science Foundation of China(No.52274400)+1 种基金the Project of Zhongyuan Critical Metals Laboratory,China(No.GJJSGFZD202302)the Science and Technology Project of Henan Province,China(No.232102230044)。
文摘The hydrogen reduction kinetics of tungsten trioxide(WO_(3))was investigated via non-isothermal thermogravimetric analysis.Under the local gas-solid reduction conditions,the particle morphology of tungsten powders was found to be consistent with that of raw material WO_(3).The removal of oxygen from tungsten oxide during hydrogen reduction led to the formation of porous structures between the reduced particles,which were obviously different from the polyhedral single-crystal configuration of tungsten powders obtained via chemical vapor deposition.Moreover,the two-stage hydrogen reduction mechanisms of WO_(3) under the local gas-solid reduction conditions can be described using the composite autocatalytic function.The activation energies of the first and second stages of the hydrogen reduction of WO_(3) were determined to be 121 and 135 kJ/mol,respectively.
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financially supported the National Key R&D Program of China (No.2022YFA1502902)the National Natural Science Foundation of China (NSFC,Nos.22475152 and U21A20286)the 111 Project of China (No.D17003)。
文摘Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.
基金supported by the National Natural Science Foundation of China (Grant No.52470078)the Natural Science Foundation of Jiangxi Province (Grant No.20252BAC250042)the Key Laboratory of Jiangxi Province for Persistent Pollutants Prevention Control and Resource Reuse (Grant No.2023SSY02061)。
文摘The rapid recombination of photogenerated charge carriers and the poor stability of metal sulfides remain bottlenecks limiting their practical applications. In this study, sulfur vacancies were introduced into an S-scheme AgIn_(5)S_(8)/Bi_(2)S_(3) heterojunction via an in situ hydrothermal method. The sulfur vacancies induced charge density redistribution within the heterojunction and generated efficient active sites for electrons, thereby creating a localized electron-rich environment. The synergistic effects of the sulfur vacancies, internal electric field, and defect energy levels accelerated the separation and transfer of photogenerated charge carriers via the S-scheme pathway, thereby enhancing the visible-light photocatalytic performance, by achieving a Cr(Ⅵ) reduction efficiency of 99.6%. More importantly, the long-term stability and excellent anti-interference capability of the S-scheme AgIn_(5)S_(8)/Bi_(2)S_(3) heterojunction demonstrate its practical application potential, achieving 98.9% Cr(Ⅵ) removal from real electroplating wastewater and meeting discharge standards. This work provides a theoretical basis for constructing highly-catalytic S-scheme heterojunctions and serves as a promising solution for Cr(VI)-containing electroplating wastewater treatment.
基金the financial support from the Shandong Province colleges and universities youth innovation technology plan innovation team project(2022KJ285)the Natural Science Foundation of Shandong Province(ZR2022QE076)+1 种基金the National Natural Science Foundation of China(52202092)the Science and Technology Support Plan for Youth Innovation of Colleges and Universities of Shandong Province of China(2023KJ104).
文摘Exploring high-performance electrocatalysts for the nitrate reduction reaction(NO_(3)RR)is crucial for environmental nitrate removal and ammonia synthesis.Single-atom collaboration with cluster can provide sufficient active sites for catalysts to promote NO_(3)RR,yet the unclear synergistic effect between the two hinders their rational design.Herein,a series of Ir_(3)clusters and metal single atoms co-embedded in graphitic carbon nitride(g-CN)catalysts(Ir_(3)M1)were constructed,and the synergistic effects of Ir_(3)clusters and M1 single atoms on the NO_(3)RR catalytic mechanism and activity were systematically explored using density functional theory(DFT)calculations combined with machine learning.Comprehensive evaluations of structural stability and catalytic activity demonstrate that the synergy between single atoms and clusters effectively balances the adsorption energies of key intermediates,yielding exceptional catalytic performance(the limiting potential of Ir_(3)Ti_(1)can reach−0.22 V).Machine learning models further clarify the synergistic mechanism,where the geometric configurations of clusters serve as critical features for modulating the catalytic activity of single-atom sites,whereas the electronic structures of single atoms directly govern the reactivity of cluster sites.This DFT-machine learning approach provides theoretical guidelines for catalyst design and a predictive framework for efficient NO_(3)RR electrocatalysts.
