For the Hardy space H_E^2(R) over a ?at unitary vector bundle E on a ?nitely connected domain R, let TE be the bundle shift as [3]. If B is a reductive algebra containing every operator ψ(TE) for any rational functi...For the Hardy space H_E^2(R) over a ?at unitary vector bundle E on a ?nitely connected domain R, let TE be the bundle shift as [3]. If B is a reductive algebra containing every operator ψ(TE) for any rational function ψ with poles outside of R, then B is self adjoint.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
Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements hav...Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.展开更多
Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied p...Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.展开更多
CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organ...CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.展开更多
The catalytic transferred of small molecules into high-value chemical products in green methods are highly perused,and has obtained huge attention.In this field,great progress has been achieved during the past five ye...The catalytic transferred of small molecules into high-value chemical products in green methods are highly perused,and has obtained huge attention.In this field,great progress has been achieved during the past five years.Followed by the roadmap(Chinese Chemical Letters,2019,30,2089-2109)written by us before five years,we think that it should be updated to give more insights in this field.Thus,we write the present roadmap based on the fast changed background.In this roadmap,oxygen and carbon dioxide reduction reactions(including at high temperature),photocatalytic hydrogen generation and carbon dioxide reduction reactions,(photo)electrocatalytic reduction of O_(2)to H_(2)O_(2)and NH_(3)generated from N_(2) are discussed.The progress and challenges in above catalytic processes are given.We believe this manuscript will give the researchers more suggestions and help them to obtain useful information in this field.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.
MXene derivatives are notable two-dimensional nanomaterials with numerous prospective applications in the domains of energy development.MXene derivative,MBene,diversifies its focus on energy storage and harvesting due...MXene derivatives are notable two-dimensional nanomaterials with numerous prospective applications in the domains of energy development.MXene derivative,MBene,diversifies its focus on energy storage and harvesting due to its exceptional electrical conductivity,structural flexibility,and mechanical properties.This comprehensive review describes the sandwich-like structure of the synthesized MBene,derived from its multilayered parent material and its distinct chemical framework to date.The fields of focus encompass the investigation of novel MBenes,the study of phase-changing mechanisms,and the examination of hex-MBenes,ortho-MBenes,tetra-MBenes,tri-MBenes,and MXenes with identical transition metal components.A critical analysis is also provided on the electrochemical mechanism and performance of MBene in energy storage(Li/Na/Mg/Ca/Li–S batteries and supercapacitors),as well as conversion and harvesting(CO_(2) reduction,and nitrogen reduction reactions).The persistent difficulties associated with conducting experimental synthesis and establishing artificial intelligence-based forecasts are extensively deliberated alongside the potential and forthcoming prospects of MBenes.This review provides a single platform for an overview of the MBene’s potential in energy storage and harvesting.展开更多
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
A series of leaching and electrochemical experiments were conducted to elucidate the critical role of hydrogen sulfide(H_(2)S)in copper-driven reduction of chalcopyrite.Results demonstrate that in the absence of H_(2)...A series of leaching and electrochemical experiments were conducted to elucidate the critical role of hydrogen sulfide(H_(2)S)in copper-driven reduction of chalcopyrite.Results demonstrate that in the absence of H_(2)S,metallic copper converts chalcopyrite into bornite(Cu_(5)FeS_(4)).However,the introduction of H_(2)S promotes the formation of chalcocite(Cu_(2)S)by altering the oxidation pathway of copper.Electrochemical analysis demonstrates that the presence of H₂S significantly reduces the corrosion potential of copper from 0.251 to−0.223 V(vs SHE),reaching the threshold necessary for the formation of Cu_(2)S.Nevertheless,excessive H_(2)S triggers sulfate reduction via the reaction of 8Cu+H_(2)SO_(4)+3H_(2)S=4Cu_(2)S+4H_(2)O(ΔG=−519.429 kJ/mol at 50℃),leading to inefficient copper utilization.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 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
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
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
Chiral benzylic amines are important motifs in medicines.A dicationic nickel complex of chiral diphosphine(R)-Ph-BPE promotes highly enantioselective reductive amination of aryl alkyl ketones with arylamines using iso...Chiral benzylic amines are important motifs in medicines.A dicationic nickel complex of chiral diphosphine(R)-Ph-BPE promotes highly enantioselective reductive amination of aryl alkyl ketones with arylamines using isopropanol as hydrogen source.The reaction is easily scaled up in a gram-scale synthesis using 1 mol% nickel catalyst and it is applied to an asymmetric synthesis of(S)-rivastigmine.Building on this success,we achieved rare examples of asymmetric hydrogen borrowing reactions with arylamines using an Earth-abundant 3d metal,nickel.展开更多
Environmental pollution,energy consumption,and greenhouse gas emissions are critical global issues.To address these challenges,optimizing skimmer coatings is a major step in commercializing cleaning oil stains.This re...Environmental pollution,energy consumption,and greenhouse gas emissions are critical global issues.To address these challenges,optimizing skimmer coatings is a major step in commercializing cleaning oil stains.This research presents a novel approach to creating and refining oil absorbent coatings,introducing a unique oil spill removal skimmer enhanced with a super hydrophobic polyaniline(PANI)nanofiber coating.The goal of this study was to improve oil absorption performance,increase the contact angle,lower drag,reduce energy consumption,achieve high desirability,and lower production costs.PANI treated with hydrochloric acid was a key focus as it resulted in higher porosity and smaller pore diameters,providing a larger surface area,which are crucial factors for boosting oil absorption and minimizing drag.To optimize optimal nanofiber morphology,PANI synthesized with methanesulfonic acid was first dedoped and then redoped with hydrochloric acid.After optimization,the most effective skimmer coating was achieved using a formulation consisting of 0.1%PANI,an ammonium persulfate/aniline ratio of 0.4,and an acid/aniline ratio of 9.689,along with redoped PANI nanofibers.The optimized skimmer exhibited a remarkable contact angle of 177.477°.The coating achieved drag reduction of 32%,oil absorption of 88.725%,a cost of$1.710,and a desirability rating of 78.5%.In this study,an optimized skimmer coat containing super hydrophobic coat-PANI nanofibers was fabricated.By enhancing contact angle and reducing drag,these coatings increased the skimmer performance by improving oil absorption and reducing fuel consumption.展开更多
基金Project Supported by Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJQN201801110)Chongqing Science and Technology Commission(CSTC2015jcyjA00045,cstc2018jcyjA2248)and NSFC(11871127)
文摘For the Hardy space H_E^2(R) over a ?at unitary vector bundle E on a ?nitely connected domain R, let TE be the bundle shift as [3]. If B is a reductive algebra containing every operator ψ(TE) for any rational function ψ with poles outside of R, then B is self adjoint.
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.
基金financially supported by the National Natural Science Foundation of China (22350410386,W2412116,22375200,U22A202175,21961142006)。
文摘Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.
基金supported by grants from the Natural Science Foundation of China(22362031 and 21805121)the Science and Technology Project of Yunnan Province(2019FD137)。
文摘Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.
文摘CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.
基金supported by the National Natural Science Foundation of China(Nos.22268003,22102095,52204320,U20A20246 and 12275199,U22A20418,22075196,21972110,52202208)National Key Research and Development Program of China(Nos.2023YFA1507903,2022YFB3803600,2022YFB4002501)+9 种基金SINOPEC(Beijing)Research Institute of Chemical Industry Co.,Ltd.(No.223239)the Fundamental Research Funds for the Central Universities(No.CCNU22JC017)the Postdoctoral Science Foundation of China(No.2021M692535)the Natural Science Foundation of Shaanxi Province(No.2022JQ-095)the Basic Research Project Foundation of Xi’an Jiaotong University(No.xzy012024012)the Youth Foundation of State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE2131)the Russian Science Foundation(No.22-13-00035)the Ministry of Science and Higher Education within the framework of a State Assignment of the Ioffe Institute,Russian Academy of Sciences(No.FFUG-2024-0036)Yunnan Fundamental Research Projects(No.202305AF150116)the Research Project Supported by Shanxi Scholarship Council of China(No.2022-050)。
文摘The catalytic transferred of small molecules into high-value chemical products in green methods are highly perused,and has obtained huge attention.In this field,great progress has been achieved during the past five years.Followed by the roadmap(Chinese Chemical Letters,2019,30,2089-2109)written by us before five years,we think that it should be updated to give more insights in this field.Thus,we write the present roadmap based on the fast changed background.In this roadmap,oxygen and carbon dioxide reduction reactions(including at high temperature),photocatalytic hydrogen generation and carbon dioxide reduction reactions,(photo)electrocatalytic reduction of O_(2)to H_(2)O_(2)and NH_(3)generated from N_(2) are discussed.The progress and challenges in above catalytic processes are given.We believe this manuscript will give the researchers more suggestions and help them to obtain useful information in this field.
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supported by the National Natural Science Foundation of China(No.52302241 and 22225801)the Major Science and Technology Programs of Henan Province(241100240200)the China Postdoctoral Science Foundation(No.2023M730940).
文摘MXene derivatives are notable two-dimensional nanomaterials with numerous prospective applications in the domains of energy development.MXene derivative,MBene,diversifies its focus on energy storage and harvesting due to its exceptional electrical conductivity,structural flexibility,and mechanical properties.This comprehensive review describes the sandwich-like structure of the synthesized MBene,derived from its multilayered parent material and its distinct chemical framework to date.The fields of focus encompass the investigation of novel MBenes,the study of phase-changing mechanisms,and the examination of hex-MBenes,ortho-MBenes,tetra-MBenes,tri-MBenes,and MXenes with identical transition metal components.A critical analysis is also provided on the electrochemical mechanism and performance of MBene in energy storage(Li/Na/Mg/Ca/Li–S batteries and supercapacitors),as well as conversion and harvesting(CO_(2) reduction,and nitrogen reduction reactions).The persistent difficulties associated with conducting experimental synthesis and establishing artificial intelligence-based forecasts are extensively deliberated alongside the potential and forthcoming prospects of MBenes.This review provides a single platform for an overview of the MBene’s potential in energy storage and harvesting.
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financially supported by the National Key Research and Development Program of China (No. 2022YFC2105300)。
文摘A series of leaching and electrochemical experiments were conducted to elucidate the critical role of hydrogen sulfide(H_(2)S)in copper-driven reduction of chalcopyrite.Results demonstrate that in the absence of H_(2)S,metallic copper converts chalcopyrite into bornite(Cu_(5)FeS_(4)).However,the introduction of H_(2)S promotes the formation of chalcocite(Cu_(2)S)by altering the oxidation pathway of copper.Electrochemical analysis demonstrates that the presence of H₂S significantly reduces the corrosion potential of copper from 0.251 to−0.223 V(vs SHE),reaching the threshold necessary for the formation of Cu_(2)S.Nevertheless,excessive H_(2)S triggers sulfate reduction via the reaction of 8Cu+H_(2)SO_(4)+3H_(2)S=4Cu_(2)S+4H_(2)O(ΔG=−519.429 kJ/mol at 50℃),leading to inefficient copper utilization.
基金supports of the National Natural Science Foundation of China(NSFC)(52021004,52394202)key project of the Joint Fund for Innovation and Development of Chongqing Natural Science Foundation(CSTB2022NSCQ-LZX0013)+1 种基金the National Natural Science Foundation of China(NSFC)(52301232,and 52476056)the Natural Science Foundation of Chongqing Province(2024NSCQ-MSX1109).
文摘Controllable synthesis of ultrathin metallene nanosheets and rational design of their spatial arrangement in favor of electrochemical catalysis are critical for their renewable energy applications.Here,a biomimetic design of“Trunk-Branch-Leaf”strategy is proposed to prepare the ultrathin edge-riched Zn-ene“leaves”with a thickness of~2.5 nm,adjacent Zn-ene cross-linked with each other,which are supported by copper nanoneedle“branches”on copper mesh“trunks,”named as Zn-ene/Cu-CM.The resulting superstructure enables the formation of an interconnected network and multiple channels,which can be used as an electrocatalytic CO_(2) reduction reaction(CO_(2)RR)electrode to allow a fast charge and mass transfer as well as a large electrolyte reservoir.By virtue of the distinctive structure,the obtained Zn-ene/Cu-CM electrode exhibits excellent selectivity and activity toward CO production with a maximum Faradaic efficiency of 91.3%and incredible partial current density up to 40 mA cm^(−2),outperforming most of the state-of-the-art Zn-based electrodes for CO_(2) reduction.The phenolphthalein color probe combined with in situ attenuated total reflection-infrared spectroscopy uncovered the formation of the localized pseudo-alkaline microenvironment at the interface of the Zn-ene/Cu-CM electrode.Theoretical calculations confirmed that the localized pH as the origin is responsible for the adsorption of CO_(2) at the interface and the generation of *COOH and *CO intermediates.This study offers valuable insights into developing efficient electrodes through synergistic regulation of reaction microenvironments and active sites,thereby facilitating the electrolysis of practical CO_(2) conversion.
基金Funded by the 111 Project(No.B17034)Open Project of Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle(No.ZDSYS202212)+1 种基金Innovative Research Team Development Program of Ministry of Education of China(No.IRT_17R83)the Science and Technology Project of China Southern Power Grid Co.,Ltd.(No.GDKJXM20222546)。
文摘The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a series of RuCo/C catalysts were synthesized by NaBH4 reduction method under the premise that the total metal mass percentage was 20%.X-ray diffraction(XRD)patterns and scanning electron microscopy(SEM)confirmed the formation of single-phase nanoparticles with an average size of 33 nm.Cyclic voltammograms(CV)and linear sweep voltammograms(LSV)tests indicated that RuCo(2:1)/C catalyst had the optimal ORR properties.Additionally,the RuCo(2:1)/C catalyst remarkably sustained 98.1% of its activity even after 3000 cycles,surpassing the performance of Pt/C(84.8%).Analysis of the elemental state of the catalyst surface after cycling using X-ray photoelectron spectroscopy(XPS)revealed that the Ru^(0) percentage of RuCo(2:1)/C decreased by 2.2%(from 66.3% to 64.1%),while the Pt^(0) percentage of Pt/C decreased by 7.1%(from 53.3% to 46.2%).It is suggested that the synergy between Ru and Co holds the potential to pave the way for future low-cost and highly stable ORR catalysts,offering significant promise in the context of PEMFCs.
基金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supported by the National Natural Science Foundation of China(Nos.22271007,W2431014)Peking University Shenzhen Graduate School+2 种基金State Key Laboratory of Chemical OncogenomicsShenzhen Key Laboratory of Chemical GenomicsShenzhen Bay Laboratory.
文摘Chiral benzylic amines are important motifs in medicines.A dicationic nickel complex of chiral diphosphine(R)-Ph-BPE promotes highly enantioselective reductive amination of aryl alkyl ketones with arylamines using isopropanol as hydrogen source.The reaction is easily scaled up in a gram-scale synthesis using 1 mol% nickel catalyst and it is applied to an asymmetric synthesis of(S)-rivastigmine.Building on this success,we achieved rare examples of asymmetric hydrogen borrowing reactions with arylamines using an Earth-abundant 3d metal,nickel.
文摘Environmental pollution,energy consumption,and greenhouse gas emissions are critical global issues.To address these challenges,optimizing skimmer coatings is a major step in commercializing cleaning oil stains.This research presents a novel approach to creating and refining oil absorbent coatings,introducing a unique oil spill removal skimmer enhanced with a super hydrophobic polyaniline(PANI)nanofiber coating.The goal of this study was to improve oil absorption performance,increase the contact angle,lower drag,reduce energy consumption,achieve high desirability,and lower production costs.PANI treated with hydrochloric acid was a key focus as it resulted in higher porosity and smaller pore diameters,providing a larger surface area,which are crucial factors for boosting oil absorption and minimizing drag.To optimize optimal nanofiber morphology,PANI synthesized with methanesulfonic acid was first dedoped and then redoped with hydrochloric acid.After optimization,the most effective skimmer coating was achieved using a formulation consisting of 0.1%PANI,an ammonium persulfate/aniline ratio of 0.4,and an acid/aniline ratio of 9.689,along with redoped PANI nanofibers.The optimized skimmer exhibited a remarkable contact angle of 177.477°.The coating achieved drag reduction of 32%,oil absorption of 88.725%,a cost of$1.710,and a desirability rating of 78.5%.In this study,an optimized skimmer coat containing super hydrophobic coat-PANI nanofibers was fabricated.By enhancing contact angle and reducing drag,these coatings increased the skimmer performance by improving oil absorption and reducing fuel consumption.
