Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microp...Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microporous molecular sieves(HZSMu)with a Si/Al atomic ratio of 150,synthesized in the laboratory,were prepared via hydrothermal synthesis.These supports were impregnated with 2.4%Co using the incipient wetness impregnation method and subsequently modified by introducing the metal additives Zr and Sn.Notably,the Co-Sn/HZSMu catalyst exhibited the highest stability,achieving a propylene selectivity of 95.3% within 400 min while maintaining robust activity.A series of characterization analyses reveal that the HZSMu molecular sieve possesses distinctive weaving properties.The synergistic effect between mesopores facilitates the adsorption and activation of reactants while preventing pore blockage,thus promoting the rapid diffusion of reactants on its surface.The incorporation of the metal additive Sn promotes the uniform dispersion of Co,mitigating the occurrence of side reactions and enhancing the catalytic performance and reaction stability of the catalyst.展开更多
Surface chemical properties of supports have an important influence on active sites and their catalytic behavio r.Here,we fabricated a series of cobalt-based catalysts supported by carbon layer-coated ordered mesoporo...Surface chemical properties of supports have an important influence on active sites and their catalytic behavio r.Here,we fabricated a series of cobalt-based catalysts supported by carbon layer-coated ordered mesoporous silica(OMS) composites for higher alcohol synthesis(HAS).The carbon layers were derived from different sources and uniformly coated on the porous surface of OMS.Combined with the characterization results of carbonized catalysts,it is demonstrated that the carbon layer-coated supports significantly enhanced the metal dispersion and increased the ratio of Co2+ to Co0 sites,which further increased the CO conversion and alcohols selectivity.Moreover,it is found that the catalytic activity changed in line with the amount of defects and surface oxygenic groups of carbon layers,which re sulted from the different carbon sources.The highest space time yield of C2+OH was 27.5 mmol gcat-1h-1)obtained by the catalyst coated with glucose-derived carbon layer.But the carbon source is not the key factor influencing the distribution of Co-Co2+ dual sites and shows little effect on selectivity in HAS.These results may guide for further design of carbon supported catalysts.展开更多
The reverse water-gas shift(RWGS)reaction holds great promise for CO_(2)reduction and achieving carbon neutrality,particularly when driven by renewable and abundant solar energy.Among various investigated catalysts,Co...The reverse water-gas shift(RWGS)reaction holds great promise for CO_(2)reduction and achieving carbon neutrality,particularly when driven by renewable and abundant solar energy.Among various investigated catalysts,Co-based materials have demonstrated high catalytic activity for CO_(2)hydrogenation,and the easily accessible Co or CoO_(x)catalysts tend to produce CH_(4)(via the Sabatier reaction)rather than CO(via the RWGS reaction)at relatively low temperatures(≤400℃).Besides the composition tuning to construct specific active sites(such as forming Co_(2)C),the manipulation of the chemical microenvironment is also considered a highly effective strategy for regulating product selectivity,as have been broadly demonstrated in electrochemistry and zeolite research fields.Herein,alkaline Sr sites aiming at enhancing the CO_(2)coverage at catalyst surface are placed in close proximity to the catalytically active Co centers,thus offering balanced supply of reactants within the reactive zone.The asdesigned SrCoO_(x)catalyst through in situ decomposition of the SrCoO_(2).52 precursor exhibits a significant enhancement in CO selectivity(from 42%to 91%)and exceptional stability throughout a 300-h continuous reaction.This work broadens the application scope of chemical microenvironment manipulation strategies and introduces a novel avenue for future photothermal catalyst development.展开更多
Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction(OER).Considerable research efforts have shown that self-reconstruction occurs on these nanomaterials under ...Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction(OER).Considerable research efforts have shown that self-reconstruction occurs on these nanomaterials under operating conditions of OER process.However,most of them undergo incomplete reconstruction with limited thickness of reconstruction layer,leading to low component utilization and arduous exploration of real catalytic mechanism.Herein,we identify the dynamic behaviors in complete reconstruction of Co-based complexes during OER.The hollow phytic acid(PA)cross-linked CoFe-based complex nanoboxes with porous nanowalls are designed because of their good electrolyte penetration and mass transport ability,in favor of the fast and complete reconstruction.A series of experiment characterizations demonstrate that the reconstruction process includes the fast substitution of PA by OH-to form Co(Fe)(OH)xand subsequent potential-driven oxidation to Co(Fe)OOH.The obtained CoFeOOH delivers a low overpotential of 290 mV at a current density of 10 mA cm^(-2)and a long-term stability.The experiment results together with theory calculations reveal that the Fe incorporation can result in the electron rearrangement of reconstructed CoFeOOH and optimization of their electronic structure,accounting for the enhanced OER activity.The work provides new insights into complete reconstruction of metal-based complexes during OER and offers guidelines for rational design of high-performance electrocatalysts.展开更多
Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,a...Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.展开更多
Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and...Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.展开更多
To explain the precipitation mechanism ofχphase in Co-based superalloys,the microstructural evolution of Co−Ti−Mo superalloys subjected to aging was investigated by X-ray diffraction(XRD),scanning electron microscope...To explain the precipitation mechanism ofχphase in Co-based superalloys,the microstructural evolution of Co−Ti−Mo superalloys subjected to aging was investigated by X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscope(TEM).The results show that the needle-likeχphase is mainly composed ofD0_(19)-Co_(3)(Ti,Mo),which is transformed from L1_(2-γ′)phase,and a specific orientation relationship exists between them.χphase is nucleated through the shearing ofγ′phase due to the influence of stacking fault.The crystal orientation relationship between L1_(2) andD0_(19)can be confirmed as{111}L1_(2)//{0001}_(D0_(19)),and<112>_(L1_(2))//<1100>_(D0_(19)).The growth ofD0_(19-χ)phase depends on the diffusions of Ti and Mo,and consumes a large number of elements.This progress leads to the appearance ofγ′precipitation depletion zone(PDZ)aroundD0_(19-χ)phase.The addition of Ni improves the stability of L1_(2-γ′)phase and the mechanical properties of Co-based superalloys.展开更多
Hydroformylation of olefins is one of the highest-volume industrial reactions to meet the vast demands for aldehydes as well as their derivatives.Homogeneous Co complexes were the original catalysts industrialized sin...Hydroformylation of olefins is one of the highest-volume industrial reactions to meet the vast demands for aldehydes as well as their derivatives.Homogeneous Co complexes were the original catalysts industrialized since 1960s.Heterogeneous catalysis is considered superior owing to the facile separation of catalysts from products,shorter technical process,and reduced manufacturing costs.Unexpectedly,there has not been a single case of plant using heterogenized Co-based catalyst successfully.To address the separation issue and understand the catalytic mechanism of the reactions,this review summarizes the progress in heterogeneous systems and provides a detailed discussion of their catalytic performance.Strategies for stabilizing Co species through support modification and additive incorporation are carefully considered to elucidate why heterogeneous systems have not yet succeeded on an industrial scale.Furthermore,we provide our insights for the development of heterogeneous catalytic hydroformylation,including the challenges,opportunities,and outlooks.The aim is to deepen the fundamental understanding of heterogeneous alkene hydroformylation,guiding the community's research efforts towards realizing its successful application in the future.展开更多
Combining terrestrial biomass as the reductant with submarine-type hydrothermal environments for CO_(2)reduction represents a possible approach for novel energy production systems that sustainably circulate carbon.How...Combining terrestrial biomass as the reductant with submarine-type hydrothermal environments for CO_(2)reduction represents a possible approach for novel energy production systems that sustainably circulate carbon.However,increasing the reductive power of biomass is the main limitation of this potential method.Herein,we demonstrate that Co-doped with small amounts of Pd enhances the reduction of CO_(2)by selectively producing an active intermediate from carbohydrates.This catalytic reaction utilized glucose as a reductant to achieve high formate production efficiency(458.6 g kg^(-1))with nearly 100%selectivity with 7.5 wt%Pd1Co_(20)/γ–Al_(2)O_(3)at a moderate temperature of 225℃.The regulation of the electronic structure of the catalytic Co surface by the dopant Pd plays a key role in promoting the C–C bond cleavage of glucose and hydrogen transfer for CO_(2)reduction.The findings presented here indicate that biomass can serve as the hydrogen source for CO_(2)reduction and provide insight into the potential utilization of CO_(2)in sustainable industrial applications.展开更多
N-doped graphite carbon sphere coated cobalt nanoparticle catalyst(Co@C-N-900),prepared by solvothermal-calcination method,is applied to activate peroxymonosulfate(PMS)for bisphenol A(BPA)elimination.The outcomes demo...N-doped graphite carbon sphere coated cobalt nanoparticle catalyst(Co@C-N-900),prepared by solvothermal-calcination method,is applied to activate peroxymonosulfate(PMS)for bisphenol A(BPA)elimination.The outcomes demonstrate that the Co@C-N-900 could effectively activate PMS,thereby causing efficient removal of BPA in water.In addition,the Co@C-N-900/PMS system also has the advantages of low metal leaching,applicability in high salinity environments,good selectivity and stability.Further investigations using electron paramagnetic resonance,chronoamperometry,and quenching experiments demonstrated that the Co@C-N-900/PMS system is a typical non-radical route with singlet oxygen(^(1)O_(2))as the main reactive oxygen species(ROS).Density functional theory calculations(DFT)indicate that N-doping can effectively regulate the charge distribution on the catalyst surface,generating acidic/alkaline sites favorable for PMS adsorption and activation.Furthermore,it also can enhance the interaction and charge transfer capacity between the Co@C-N-900 and PMS.Lastly,LC-QTOF-MS/MS analysis revealed two possible BPA degradation pathways:(1)^(1)O_(2)attacked the isopropyl group in BPA between the two phenyl groups,causingβ-scission to occur.(2)Following the oxidation of the hydroxyl group in the aromatic ring of BPA,^(1)O_(2)could cause furtherβ-scission.The prepared Co@C-N-900 catalyst is a very promising catalyst,which would offer a workable remedy for treating water pollution.展开更多
A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated...A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated imine(-CH=N-)groups and a cobalt-based MOFs(Co-hmta)structure prepared using hydrogen bonding stacking with hexamethylenetetramine(hmta)as the organic ligand.Subsequently,the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)_(3)supported metallic Co catalyst incorporating carbon-nitrogen(Co/La(OH)_(3)-CNhmta)catalyst.The catalytic results show that Co/La(OH)_(3)-CN-hmta(54%and 46%selectivity for aniline and N-phenylbenzylamine,respectively)displays superior cascade performance compared to classic Co/La(OH)_(3)-CN-nit catalyst(69%and 31%selectivity for aniline and N-phenylbenzylamine,respectively).Moreover,the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction.The Co/La(OH)_(3)-CN-hmta catalyst can be separated from the reaction system using a magnet,and it also exhibits good cyclic stability.All of these suggest that the“MOFs plus MOFs via coordination”templating method can be employed as an efficient strategy for the preparation of supported catalysts.展开更多
High levels of Al and Ti in superalloy compositions normally lead to cracking formation during the laser powder bed fusion process,while these elements are key constituents of strengthening phases.In the current study...High levels of Al and Ti in superalloy compositions normally lead to cracking formation during the laser powder bed fusion process,while these elements are key constituents of strengthening phases.In the current study,a novel Co-based superalloy with the basic chemical composition of Co-Al-W-Ta-Ti resolved this contradiction,indicating that the part was formed without cracking and simultaneously contained a large amount of strengthening precipitates in the microstructure fabricated via laser powder bed fusion.The printability,microstructures,and mechanical properties of the sample were analysed before and after heat treatment,providing a potential superalloy that can replace Ni-based superalloys fabricated by additive manufacturing in aerospace and other industries with higher temperature and more efficiency.展开更多
In this work,a series of Co-based ternary Co-Er-B bulk metallic glasses(BMGs)with excellent soft magnetic properties and high strength were developed,and the local atomic structure of a typical Co_(71.5)Er_(3.5)B_(25)...In this work,a series of Co-based ternary Co-Er-B bulk metallic glasses(BMGs)with excellent soft magnetic properties and high strength were developed,and the local atomic structure of a typical Co_(71.5)Er_(3.5)B_(25) metallic glass was studied through in situ high-energy synchrotron X-ray diffraction and ab initio molecular dynamics simulations.The results reveal that the BMG samples can be obtained in a composition region of Co_(68.5-71.5)Er_(3.5-4)B_(25-27.5) by a conventional copper-mold casting method.The Co-Er-B metallic glasses possess stronger atomic bond strengths and denser local atomic packing structure composed of a higher fraction of icosahedral-like clusters but fewer deformed body-centered cubic and crystal-like polyhedrons,and they exhibit slower atomic diffusion behaviors during solidification,as compared to Co-Y-B counterparts.The enhancement in structural stability and the retardation of atomic-ordered diffusion lead to the better glass-forming ability of the Co-Er-B alloys.The smaller magnetic anisotropy energy in the Co-Er-B metallic glasses results in a lower coercivity of less than 1.3 A/m.The Co-Er-B BMGs exhibit high-yield strength of 3560-3969 MPa along with distinct plasticity of around 0.50%.展开更多
S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB...S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.展开更多
The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation...The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts.展开更多
The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats.Due to the low reactivity of the carbonyl group in esters,a high reaction tempera...The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats.Due to the low reactivity of the carbonyl group in esters,a high reaction temperature(>250℃)is the prerequisite to ensure high conversion of esters.Here,we report a highly dispersed MoO_(x)-Ru/C bimetallic catalyst for the efficient hydrogenolysis of esters to alkanes under 150°C.The optimal catalyst exhibits>99%conversion of methyl stearate and 99%selectivity to diesel-range alkanes,reaching a high rate of up to 2.0 mmol gcat^(–1)h^(–1),5 times higher than that of Ru/C catalyst(MoO_(x)/C is inert).Integrated experimental and theoretical investigations attribute the high performance to the abundant MoO_(x)-Ru interfacial sites on the catalyst surface,which offers high activity for the C–O cleavage of esters.Furthermore,the dispersed MoO_(x)species significantly weaken the hydrocracking activity of the metallic Ru for C–C bonds,thus yielding alkane products without carbon loss.This study provides a facile and novel strategy for the design of high-performance heterogeneous catalysts for the hydrodeoxygenation of biomass-derived esters to alkane products.展开更多
To improve the catalytic performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3)(LSCF)towards carbon soot,we utilized the impregnation method to incorporate Ag into the prepared LSCF catalyst.We conducted a series of cha...To improve the catalytic performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3)(LSCF)towards carbon soot,we utilized the impregnation method to incorporate Ag into the prepared LSCF catalyst.We conducted a series of characterization tests and evaluated the soot catalytic activity of the composite catalyst by comparing it with the LaCoO_(3) group,LaFeO_(3) group,and catalyst-free group.The results indicate that the Ag-LSCF composite catalyst exhibits the highest soot catalytic activity,with the characteristic temperature values of 376.3,431.1,and 473.9℃at 10%,50%,and 90%carbon soot conversion,respectively.These values are 24.8,20.2,and 23.1℃lower than those of the LSCF group.This also shows that LSCF can improve the catalytic activity of soot after compounding with Ag,and reflects the necessity of using catalysts in soot combustion reaction.XPS characterization and BET test show that Ag-LSCF has more abundant surface-adsorbed oxygen species,larger specific surface area and pore volume than LSCF,which also proves that Ag-LSCF has higher soot catalytic activity.展开更多
Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-perform...Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-performance biomass-derived ORR catalysts with an asymmetric Fe-N_(3)P configuration was prepared by a simple pyrolysis-etching technique,where carboxymethyl cellulose(CMC)was used as the carbon source,urea and 1,10-phenanthroline iron complex(FePhen)as additives,and Na_(3)PO_(4)as the phosphorus dopant and a pore-forming agent.The CMC-derived FeNPC catalyst displayed a large specific area(BET:1235 m^(2)g^(-1))with atomically dispersed Fe-N_(3)P active sites,which exhibited superior ORR activity and stability in alkaline solution(E_(1/2)=0.90 V vs.RHE)and Zn-air batteries(P_(max)=149 mW cm^(-2))to commercial Pt/C catalyst(E_(1/2)=0.87 V,P_(max)=118 mW cm^(-2))under similar experimental conditions.This work provides a feasible and costeffective route toward highly efficient ORR catalysts and their application to Zn-air batteries for energy conversion.展开更多
NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.A...NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity.展开更多
Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3...Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.21968034).
文摘Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microporous molecular sieves(HZSMu)with a Si/Al atomic ratio of 150,synthesized in the laboratory,were prepared via hydrothermal synthesis.These supports were impregnated with 2.4%Co using the incipient wetness impregnation method and subsequently modified by introducing the metal additives Zr and Sn.Notably,the Co-Sn/HZSMu catalyst exhibited the highest stability,achieving a propylene selectivity of 95.3% within 400 min while maintaining robust activity.A series of characterization analyses reveal that the HZSMu molecular sieve possesses distinctive weaving properties.The synergistic effect between mesopores facilitates the adsorption and activation of reactants while preventing pore blockage,thus promoting the rapid diffusion of reactants on its surface.The incorporation of the metal additive Sn promotes the uniform dispersion of Co,mitigating the occurrence of side reactions and enhancing the catalytic performance and reaction stability of the catalyst.
基金support from the National Natural Science Foundation of China(Nos.U1462204,21706184)the National Postdoctoral Program for Innovative Talents of China(No.BX20180221)。
文摘Surface chemical properties of supports have an important influence on active sites and their catalytic behavio r.Here,we fabricated a series of cobalt-based catalysts supported by carbon layer-coated ordered mesoporous silica(OMS) composites for higher alcohol synthesis(HAS).The carbon layers were derived from different sources and uniformly coated on the porous surface of OMS.Combined with the characterization results of carbonized catalysts,it is demonstrated that the carbon layer-coated supports significantly enhanced the metal dispersion and increased the ratio of Co2+ to Co0 sites,which further increased the CO conversion and alcohols selectivity.Moreover,it is found that the catalytic activity changed in line with the amount of defects and surface oxygenic groups of carbon layers,which re sulted from the different carbon sources.The highest space time yield of C2+OH was 27.5 mmol gcat-1h-1)obtained by the catalyst coated with glucose-derived carbon layer.But the carbon source is not the key factor influencing the distribution of Co-Co2+ dual sites and shows little effect on selectivity in HAS.These results may guide for further design of carbon supported catalysts.
基金supported by the National Natural Science Foundation of China(22379065,22309080,22372078)the National Science Fund for Distinguished Young Scholars(22025202)+1 种基金the National Key Research and Development Program of China(2020YFA0710302)the Natural Science Foundation of Jiangsu Province of China(BK20232021)。
文摘The reverse water-gas shift(RWGS)reaction holds great promise for CO_(2)reduction and achieving carbon neutrality,particularly when driven by renewable and abundant solar energy.Among various investigated catalysts,Co-based materials have demonstrated high catalytic activity for CO_(2)hydrogenation,and the easily accessible Co or CoO_(x)catalysts tend to produce CH_(4)(via the Sabatier reaction)rather than CO(via the RWGS reaction)at relatively low temperatures(≤400℃).Besides the composition tuning to construct specific active sites(such as forming Co_(2)C),the manipulation of the chemical microenvironment is also considered a highly effective strategy for regulating product selectivity,as have been broadly demonstrated in electrochemistry and zeolite research fields.Herein,alkaline Sr sites aiming at enhancing the CO_(2)coverage at catalyst surface are placed in close proximity to the catalytically active Co centers,thus offering balanced supply of reactants within the reactive zone.The asdesigned SrCoO_(x)catalyst through in situ decomposition of the SrCoO_(2).52 precursor exhibits a significant enhancement in CO selectivity(from 42%to 91%)and exceptional stability throughout a 300-h continuous reaction.This work broadens the application scope of chemical microenvironment manipulation strategies and introduces a novel avenue for future photothermal catalyst development.
基金National Natural Science Foundation of China(22478310,U21A20286 and 22206054)。
文摘Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction(OER).Considerable research efforts have shown that self-reconstruction occurs on these nanomaterials under operating conditions of OER process.However,most of them undergo incomplete reconstruction with limited thickness of reconstruction layer,leading to low component utilization and arduous exploration of real catalytic mechanism.Herein,we identify the dynamic behaviors in complete reconstruction of Co-based complexes during OER.The hollow phytic acid(PA)cross-linked CoFe-based complex nanoboxes with porous nanowalls are designed because of their good electrolyte penetration and mass transport ability,in favor of the fast and complete reconstruction.A series of experiment characterizations demonstrate that the reconstruction process includes the fast substitution of PA by OH-to form Co(Fe)(OH)xand subsequent potential-driven oxidation to Co(Fe)OOH.The obtained CoFeOOH delivers a low overpotential of 290 mV at a current density of 10 mA cm^(-2)and a long-term stability.The experiment results together with theory calculations reveal that the Fe incorporation can result in the electron rearrangement of reconstructed CoFeOOH and optimization of their electronic structure,accounting for the enhanced OER activity.The work provides new insights into complete reconstruction of metal-based complexes during OER and offers guidelines for rational design of high-performance electrocatalysts.
基金National Natural Science Foundation of China(52071126)Natural Science Foundation of Tianjin City,China(22JCQNJC01240)+2 种基金Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z1009G)Special Funds for Science and Technology Innovation in Hebei(2022X19)Anhui Provincial Natural Science Foundation(2308085ME135)。
文摘Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.
基金supported by the National Natural Science Foundation of China(51872115,12234018 and 52101256)Beijing Synchrotron Radiation Facility(BSRF,4B9A)。
文摘Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.
基金The financial supports from the National Natural Science Foundation of China(Nos.52171107,52201203)the National Natural Science Foundation of China-Joint Fund of Iron and Steel Research(No.U1960204)the“333”Talent Project of Hebei Province,China(No.B20221001)are gratefully acknowledged.
文摘To explain the precipitation mechanism ofχphase in Co-based superalloys,the microstructural evolution of Co−Ti−Mo superalloys subjected to aging was investigated by X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscope(TEM).The results show that the needle-likeχphase is mainly composed ofD0_(19)-Co_(3)(Ti,Mo),which is transformed from L1_(2-γ′)phase,and a specific orientation relationship exists between them.χphase is nucleated through the shearing ofγ′phase due to the influence of stacking fault.The crystal orientation relationship between L1_(2) andD0_(19)can be confirmed as{111}L1_(2)//{0001}_(D0_(19)),and<112>_(L1_(2))//<1100>_(D0_(19)).The growth ofD0_(19-χ)phase depends on the diffusions of Ti and Mo,and consumes a large number of elements.This progress leads to the appearance ofγ′precipitation depletion zone(PDZ)aroundD0_(19-χ)phase.The addition of Ni improves the stability of L1_(2-γ′)phase and the mechanical properties of Co-based superalloys.
文摘Hydroformylation of olefins is one of the highest-volume industrial reactions to meet the vast demands for aldehydes as well as their derivatives.Homogeneous Co complexes were the original catalysts industrialized since 1960s.Heterogeneous catalysis is considered superior owing to the facile separation of catalysts from products,shorter technical process,and reduced manufacturing costs.Unexpectedly,there has not been a single case of plant using heterogenized Co-based catalyst successfully.To address the separation issue and understand the catalytic mechanism of the reactions,this review summarizes the progress in heterogeneous systems and provides a detailed discussion of their catalytic performance.Strategies for stabilizing Co species through support modification and additive incorporation are carefully considered to elucidate why heterogeneous systems have not yet succeeded on an industrial scale.Furthermore,we provide our insights for the development of heterogeneous catalytic hydroformylation,including the challenges,opportunities,and outlooks.The aim is to deepen the fundamental understanding of heterogeneous alkene hydroformylation,guiding the community's research efforts towards realizing its successful application in the future.
基金supported by the National Natural Science Foundation of China(21978170 and 22108171)the Natural Science Foundation of Shanghai(23ZR1435200)the Shanghai Key Laboratory of Hydrogen Science&Center of Hydrogen Science,Shanghai Jiao Tong University,China.
文摘Combining terrestrial biomass as the reductant with submarine-type hydrothermal environments for CO_(2)reduction represents a possible approach for novel energy production systems that sustainably circulate carbon.However,increasing the reductive power of biomass is the main limitation of this potential method.Herein,we demonstrate that Co-doped with small amounts of Pd enhances the reduction of CO_(2)by selectively producing an active intermediate from carbohydrates.This catalytic reaction utilized glucose as a reductant to achieve high formate production efficiency(458.6 g kg^(-1))with nearly 100%selectivity with 7.5 wt%Pd1Co_(20)/γ–Al_(2)O_(3)at a moderate temperature of 225℃.The regulation of the electronic structure of the catalytic Co surface by the dopant Pd plays a key role in promoting the C–C bond cleavage of glucose and hydrogen transfer for CO_(2)reduction.The findings presented here indicate that biomass can serve as the hydrogen source for CO_(2)reduction and provide insight into the potential utilization of CO_(2)in sustainable industrial applications.
基金the financial support from Sichuan Science and Technology Program(No.2023NSFSC0847)Scientific Research and Innovation Team Program of Sichuan University of Science and Technology(No.SUSE652A003)+3 种基金Talent Introduction Project of Sichuan University of Science and Engineering(No.2021RC03)Talent Introduction Project of Sichuan University of Science and Engineering(No.2021RC05)the Undergraduate Training Program for Innovation and Entrepreneurship(No.CX2024042)The Innovation Fund of Postgraduate,Sichuan University of Science&Engineering(No.Y2024094)。
文摘N-doped graphite carbon sphere coated cobalt nanoparticle catalyst(Co@C-N-900),prepared by solvothermal-calcination method,is applied to activate peroxymonosulfate(PMS)for bisphenol A(BPA)elimination.The outcomes demonstrate that the Co@C-N-900 could effectively activate PMS,thereby causing efficient removal of BPA in water.In addition,the Co@C-N-900/PMS system also has the advantages of low metal leaching,applicability in high salinity environments,good selectivity and stability.Further investigations using electron paramagnetic resonance,chronoamperometry,and quenching experiments demonstrated that the Co@C-N-900/PMS system is a typical non-radical route with singlet oxygen(^(1)O_(2))as the main reactive oxygen species(ROS).Density functional theory calculations(DFT)indicate that N-doping can effectively regulate the charge distribution on the catalyst surface,generating acidic/alkaline sites favorable for PMS adsorption and activation.Furthermore,it also can enhance the interaction and charge transfer capacity between the Co@C-N-900 and PMS.Lastly,LC-QTOF-MS/MS analysis revealed two possible BPA degradation pathways:(1)^(1)O_(2)attacked the isopropyl group in BPA between the two phenyl groups,causingβ-scission to occur.(2)Following the oxidation of the hydroxyl group in the aromatic ring of BPA,^(1)O_(2)could cause furtherβ-scission.The prepared Co@C-N-900 catalyst is a very promising catalyst,which would offer a workable remedy for treating water pollution.
基金Project supported by the Natural Science Foundation of Jiangsu Province (BK20210066)Natural Science Foundation of Heilongjiang Province (ZD2022E007).
文摘A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated imine(-CH=N-)groups and a cobalt-based MOFs(Co-hmta)structure prepared using hydrogen bonding stacking with hexamethylenetetramine(hmta)as the organic ligand.Subsequently,the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)_(3)supported metallic Co catalyst incorporating carbon-nitrogen(Co/La(OH)_(3)-CNhmta)catalyst.The catalytic results show that Co/La(OH)_(3)-CN-hmta(54%and 46%selectivity for aniline and N-phenylbenzylamine,respectively)displays superior cascade performance compared to classic Co/La(OH)_(3)-CN-nit catalyst(69%and 31%selectivity for aniline and N-phenylbenzylamine,respectively).Moreover,the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction.The Co/La(OH)_(3)-CN-hmta catalyst can be separated from the reaction system using a magnet,and it also exhibits good cyclic stability.All of these suggest that the“MOFs plus MOFs via coordination”templating method can be employed as an efficient strategy for the preparation of supported catalysts.
基金supported by the Shenzhen-Hong Kong Sci-ence and Technology Innovation Cooperation Zone Shenzhen Park Project(Grant No.HZQB-KCZYB-2020030)the RGC Theme-based Research Scheme(Grant No.AoE/M-402/20)+1 种基金National Nat-ural Science Foundation of China(Grant No.52250710160)Shenzhen Science and Technology Innovation Committee(Grant Nos.KQTD20170328154443162,JCYJ20210324104610029,and JCYJ20220818100613028).
文摘High levels of Al and Ti in superalloy compositions normally lead to cracking formation during the laser powder bed fusion process,while these elements are key constituents of strengthening phases.In the current study,a novel Co-based superalloy with the basic chemical composition of Co-Al-W-Ta-Ti resolved this contradiction,indicating that the part was formed without cracking and simultaneously contained a large amount of strengthening precipitates in the microstructure fabricated via laser powder bed fusion.The printability,microstructures,and mechanical properties of the sample were analysed before and after heat treatment,providing a potential superalloy that can replace Ni-based superalloys fabricated by additive manufacturing in aerospace and other industries with higher temperature and more efficiency.
基金supported by the National Natural Science Foundation of China(Grant Nos.52171153 and 51871039)supported by the Department of Energy(DOE)Office of Science(DE-AC02-06CH11357)+1 种基金financial support from the Shanghai Science and Technology Committee,China(Grant No.22JC1410300)the Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments(MFree),China(Grant No.22dz2260800).
文摘In this work,a series of Co-based ternary Co-Er-B bulk metallic glasses(BMGs)with excellent soft magnetic properties and high strength were developed,and the local atomic structure of a typical Co_(71.5)Er_(3.5)B_(25) metallic glass was studied through in situ high-energy synchrotron X-ray diffraction and ab initio molecular dynamics simulations.The results reveal that the BMG samples can be obtained in a composition region of Co_(68.5-71.5)Er_(3.5-4)B_(25-27.5) by a conventional copper-mold casting method.The Co-Er-B metallic glasses possess stronger atomic bond strengths and denser local atomic packing structure composed of a higher fraction of icosahedral-like clusters but fewer deformed body-centered cubic and crystal-like polyhedrons,and they exhibit slower atomic diffusion behaviors during solidification,as compared to Co-Y-B counterparts.The enhancement in structural stability and the retardation of atomic-ordered diffusion lead to the better glass-forming ability of the Co-Er-B alloys.The smaller magnetic anisotropy energy in the Co-Er-B metallic glasses results in a lower coercivity of less than 1.3 A/m.The Co-Er-B BMGs exhibit high-yield strength of 3560-3969 MPa along with distinct plasticity of around 0.50%.
基金financially supported by the National Natural Science Foundation of China(Nos.51602018 and 51902018)the Natural Science Foundation of Beijing Municipality(No.2154052)+3 种基金the China Postdoctoral Science Foundation(No.2014M560044)the Fundamental Research Funds for the Central Universities(No.FRF-MP-20-22)USTB Research Center for International People-to-people Exchange in Science,Technology and Civilization(No.2022KFYB007)Education and Teaching Reform Foundation at University of Science and Technology Beijing(Nos.2023JGC027,KC2022QYW06,and KC2022TS09)。
文摘S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.
基金the Canadian NRCan OERD Energy Innovation Programthe Natural Sciences and Engineering Research Council of Canada,and the Carbon Solution Program for their financial support.
文摘The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts.
文摘The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats.Due to the low reactivity of the carbonyl group in esters,a high reaction temperature(>250℃)is the prerequisite to ensure high conversion of esters.Here,we report a highly dispersed MoO_(x)-Ru/C bimetallic catalyst for the efficient hydrogenolysis of esters to alkanes under 150°C.The optimal catalyst exhibits>99%conversion of methyl stearate and 99%selectivity to diesel-range alkanes,reaching a high rate of up to 2.0 mmol gcat^(–1)h^(–1),5 times higher than that of Ru/C catalyst(MoO_(x)/C is inert).Integrated experimental and theoretical investigations attribute the high performance to the abundant MoO_(x)-Ru interfacial sites on the catalyst surface,which offers high activity for the C–O cleavage of esters.Furthermore,the dispersed MoO_(x)species significantly weaken the hydrocracking activity of the metallic Ru for C–C bonds,thus yielding alkane products without carbon loss.This study provides a facile and novel strategy for the design of high-performance heterogeneous catalysts for the hydrodeoxygenation of biomass-derived esters to alkane products.
文摘To improve the catalytic performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3)(LSCF)towards carbon soot,we utilized the impregnation method to incorporate Ag into the prepared LSCF catalyst.We conducted a series of characterization tests and evaluated the soot catalytic activity of the composite catalyst by comparing it with the LaCoO_(3) group,LaFeO_(3) group,and catalyst-free group.The results indicate that the Ag-LSCF composite catalyst exhibits the highest soot catalytic activity,with the characteristic temperature values of 376.3,431.1,and 473.9℃at 10%,50%,and 90%carbon soot conversion,respectively.These values are 24.8,20.2,and 23.1℃lower than those of the LSCF group.This also shows that LSCF can improve the catalytic activity of soot after compounding with Ag,and reflects the necessity of using catalysts in soot combustion reaction.XPS characterization and BET test show that Ag-LSCF has more abundant surface-adsorbed oxygen species,larger specific surface area and pore volume than LSCF,which also proves that Ag-LSCF has higher soot catalytic activity.
基金supported by the National Natural Science Foundation of China(No.21571062)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning to JGL,and the Fundamental Research Funds for the Central Universities(No.222201717003)。
文摘Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-performance biomass-derived ORR catalysts with an asymmetric Fe-N_(3)P configuration was prepared by a simple pyrolysis-etching technique,where carboxymethyl cellulose(CMC)was used as the carbon source,urea and 1,10-phenanthroline iron complex(FePhen)as additives,and Na_(3)PO_(4)as the phosphorus dopant and a pore-forming agent.The CMC-derived FeNPC catalyst displayed a large specific area(BET:1235 m^(2)g^(-1))with atomically dispersed Fe-N_(3)P active sites,which exhibited superior ORR activity and stability in alkaline solution(E_(1/2)=0.90 V vs.RHE)and Zn-air batteries(P_(max)=149 mW cm^(-2))to commercial Pt/C catalyst(E_(1/2)=0.87 V,P_(max)=118 mW cm^(-2))under similar experimental conditions.This work provides a feasible and costeffective route toward highly efficient ORR catalysts and their application to Zn-air batteries for energy conversion.
基金supported by the National Natural Science Foundation of China(Nos.22276182 and 22188102)the Natural Science Foundation of Fujian Province,China(No.2023J06048)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021303).
文摘NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity.
基金Research Institute for Smart Energy(CDB2)the grant from the Research Institute for Advanced Manufacturing(CD8Z)+4 种基金the grant from the Carbon Neutrality Funding Scheme(WZ2R)at The Hong Kong Polytechnic Universitysupport from the Hong Kong Polytechnic University(CD9B,CDBZ and WZ4Q)the National Natural Science Foundation of China(22205187)Shenzhen Municipal Science and Technology Innovation Commission(JCYJ20230807140402006)Start-up Foundation for Introducing Talent of NUIST and Natural Science Foundation of Jiangsu Province of China(BK20230426).
文摘Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.
