In this work, Temperature-Programmed Reduction Processes of iron oxide and 12 other kinds of promoted iron oxides were investigated. It is suggested that the reduction activation energy can be expressed as a normal di...In this work, Temperature-Programmed Reduction Processes of iron oxide and 12 other kinds of promoted iron oxides were investigated. It is suggested that the reduction activation energy can be expressed as a normal distribution. The distribution parameters were obtained by kinetic data fitting, which depends on the chemical and geometric characteristics of both the iron oxide and the promoter.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
The effect of local polymer injection on a flat-plate turbulent boundary layer was investigated experimentally,with a particular focus on the distinct mechanisms of drag reduction in the low-drag reduction(LDR)and hig...The effect of local polymer injection on a flat-plate turbulent boundary layer was investigated experimentally,with a particular focus on the distinct mechanisms of drag reduction in the low-drag reduction(LDR)and high-drag reduction(HDR)states.High-resolution measurements of the near-wall flow field were achieved using particle tracking velocimetry(PTV),while large-field measurements covering the entire boundary layer were obtained through particle image velocimetry(PIV).It is found that in the LDR state,the mean shear and turbulence intensity in the near-wall region are mildly suppressed.The influence of polymer solution is limited to the near-wall region and does not affect the self-sustaining cycle of wall-bounded turbulence.Conversely,in the HDR state,the polymer solution effectively disrupts the self-sustaining process of wall-bounded turbulence by suppressing the lifting of the low-speed streaks.Consequently,the turbulence production is attenuated.The buffer layer is extended,and the slope of the log-law region also becomes larger when polymer concentration or the Weissenberg number increases.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
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
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
Iron and steel industry is one of the main sources of air pollution emissions in China.The sintering process is an important link in the blast furnace ironmaking process,but it is also accompanied by a large number of...Iron and steel industry is one of the main sources of air pollution emissions in China.The sintering process is an important link in the blast furnace ironmaking process,but it is also accompanied by a large number of pollutants.Under the background of ultra-low emissions,iron and steel enterprises urgently need to upgrade their existing processes to address the existing process in practical application problems.In this study,a steel group in Gansu Province was taken as an example.By comparing and analyzing the pollutant emission characteristics before and after the ultra-low emission retrofit,the collaborative control effect of the combined process on SO_(2),NO_(x),particulate matter,and dioxins after the new retrofit was systematically evaluated.The results show that after the retrofit,the concentrations of particulate matter,SO_(2) and NO_(x) have dropped to near-zero levels,and the dioxin removal efficiency has reached 98.87%,with all indicators being better than the national ultra-low emission standards.The study confirms that the optimal combination of multi-pollutant collaborative treatment technologies is the key to achieving efficient emission reduction,among which selective catalytic reduction technology has a particularly significant synergistic removal effect on NO_(x) and dioxins.This study provides an important technical reference and practical basis for the ultra-low emission retrofit of the steel industry,and has important guiding significance for promoting the green retrofit of the industry.Its ultra-low emission retrofit is of great significance for achieving green and low-carbon development.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
Lewis acid(LA)and Lewis base(LB)sites on catalyst surfaces play a pivotal role in catalytic reactions.By precisely modulating the type,density,and spatial distribution of these Lewis acid/base sites,catalytic performa...Lewis acid(LA)and Lewis base(LB)sites on catalyst surfaces play a pivotal role in catalytic reactions.By precisely modulating the type,density,and spatial distribution of these Lewis acid/base sites,catalytic performance indicators such as catalytic activity,selectivity,and stability can be effectively optimized.As a result,they become essential parameters that must be considered in the design and development of high-efficiency catalysts.This study proposes a surface engineering method to accurately control the concentration of surface LA and LB sites in defect-laden In_(2)O_(3-x)(OH)_(y)(denoted as N-n%-IO),establishing three types of LB/LA stoichiometric ratios with different photocatalytic CO_(2)hydrogenation performances.It is demonstrated that the LB-rich system(LB/LA>1)shows suppressed activity.In contrast,the balanced stoichiometric ratio system(LB/LA=1)attains an optimal methanol yield(179.79μmol g^(-1)h^(-1))and selectivity(43.67%),while the LA-rich system(LB/LA<1)exhibits the best CO production rate(1913.76μmol g^(-1)h^(-1))and selectivity(94.96%).Systematic experiments disclose that the balanced LB/LA system with adjacent surface frustrated Lewis pairs(SFLPs)can effectively facilitate the adsorption/activation of reactants,stabilize intermediates,and regulate the dynamic behavior of photo-generated carriers.However,the imbalanced LB/LA systems either lack necessary active sites or can only follow an oxygen vacancy-mediated pathway during photocatalytic CO_(2)hydrogenation.This work offers a comprehensive understanding of the crucial functions of surface Lewis acid/base sites in the product distribution of solar-driven CO_(2)reduction.展开更多
文摘In this work, Temperature-Programmed Reduction Processes of iron oxide and 12 other kinds of promoted iron oxides were investigated. It is suggested that the reduction activation energy can be expressed as a normal distribution. The distribution parameters were obtained by kinetic data fitting, which depends on the chemical and geometric characteristics of both the iron oxide and the promoter.
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supported by the National Natural Science Foundation of China(Grant Nos.12125204,12388101,12502257,12472227)the Project 111 of China(Grant No.B17037)。
文摘The effect of local polymer injection on a flat-plate turbulent boundary layer was investigated experimentally,with a particular focus on the distinct mechanisms of drag reduction in the low-drag reduction(LDR)and high-drag reduction(HDR)states.High-resolution measurements of the near-wall flow field were achieved using particle tracking velocimetry(PTV),while large-field measurements covering the entire boundary layer were obtained through particle image velocimetry(PIV).It is found that in the LDR state,the mean shear and turbulence intensity in the near-wall region are mildly suppressed.The influence of polymer solution is limited to the near-wall region and does not affect the self-sustaining cycle of wall-bounded turbulence.Conversely,in the HDR state,the polymer solution effectively disrupts the self-sustaining process of wall-bounded turbulence by suppressing the lifting of the low-speed streaks.Consequently,the turbulence production is attenuated.The buffer layer is extended,and the slope of the log-law region also becomes larger when polymer concentration or the Weissenberg number increases.
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 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 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supported by the Key Research and Development Program of Gansu Province(22YF7FA070)the National Natural Science Foundation of China(22406076,22466026)the Basic Research Project of Yunnan Province(202301BE070001-017,202401CF070139,202401AS070085)。
文摘Iron and steel industry is one of the main sources of air pollution emissions in China.The sintering process is an important link in the blast furnace ironmaking process,but it is also accompanied by a large number of pollutants.Under the background of ultra-low emissions,iron and steel enterprises urgently need to upgrade their existing processes to address the existing process in practical application problems.In this study,a steel group in Gansu Province was taken as an example.By comparing and analyzing the pollutant emission characteristics before and after the ultra-low emission retrofit,the collaborative control effect of the combined process on SO_(2),NO_(x),particulate matter,and dioxins after the new retrofit was systematically evaluated.The results show that after the retrofit,the concentrations of particulate matter,SO_(2) and NO_(x) have dropped to near-zero levels,and the dioxin removal efficiency has reached 98.87%,with all indicators being better than the national ultra-low emission standards.The study confirms that the optimal combination of multi-pollutant collaborative treatment technologies is the key to achieving efficient emission reduction,among which selective catalytic reduction technology has a particularly significant synergistic removal effect on NO_(x) and dioxins.This study provides an important technical reference and practical basis for the ultra-low emission retrofit of the steel industry,and has important guiding significance for promoting the green retrofit of the industry.Its ultra-low emission retrofit is of great significance for achieving green and low-carbon development.
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.
基金supported by the National Natural Science Foundation of China(22172086,22105117)the Taishan Scholars Program of Shandong Province(202103064)the Major Basic Research Project of Shandong Province(ZR2021ZD06)。
文摘Lewis acid(LA)and Lewis base(LB)sites on catalyst surfaces play a pivotal role in catalytic reactions.By precisely modulating the type,density,and spatial distribution of these Lewis acid/base sites,catalytic performance indicators such as catalytic activity,selectivity,and stability can be effectively optimized.As a result,they become essential parameters that must be considered in the design and development of high-efficiency catalysts.This study proposes a surface engineering method to accurately control the concentration of surface LA and LB sites in defect-laden In_(2)O_(3-x)(OH)_(y)(denoted as N-n%-IO),establishing three types of LB/LA stoichiometric ratios with different photocatalytic CO_(2)hydrogenation performances.It is demonstrated that the LB-rich system(LB/LA>1)shows suppressed activity.In contrast,the balanced stoichiometric ratio system(LB/LA=1)attains an optimal methanol yield(179.79μmol g^(-1)h^(-1))and selectivity(43.67%),while the LA-rich system(LB/LA<1)exhibits the best CO production rate(1913.76μmol g^(-1)h^(-1))and selectivity(94.96%).Systematic experiments disclose that the balanced LB/LA system with adjacent surface frustrated Lewis pairs(SFLPs)can effectively facilitate the adsorption/activation of reactants,stabilize intermediates,and regulate the dynamic behavior of photo-generated carriers.However,the imbalanced LB/LA systems either lack necessary active sites or can only follow an oxygen vacancy-mediated pathway during photocatalytic CO_(2)hydrogenation.This work offers a comprehensive understanding of the crucial functions of surface Lewis acid/base sites in the product distribution of solar-driven CO_(2)reduction.
