The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction(HER)depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface.Here,a ...The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction(HER)depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface.Here,a self-standing porous tubular Mott-Schottky electrocatalyst is constructed by a self-template etching strategy,where amorphous WO_(x)(a-WO_(x))nano-matrix connects Co nanoparticles.This novel“Janus”electrocatalyst maximizes the Mott-Schottky effect by not only providing a highly exposed micro interface,but also simultaneously accelerating the water dissociation and optimizing the hydrogen desorption process.Experimental findings and theoretical calculations reveal that Co/a-WO_(x)Mott-Schottky heterointerface triggers the electron redistribution and a build-in electric field,which can not only optimize the adsorption energy of the reaction intermediates,but also facilitate the charge transfer.Thus,Co/a-WO_(x)requires an overpotential of only 36.3 mV at 10 mA·cm^(−2)and shows a small Tafel slope of 53.9 mV·dec^(−1)as well as an excellent 200-h long-term stability.This work provides a novel design strategy for maximizing the Mott-Schottky effect on promoting alkaline HER.展开更多
The oxygen reduction reaction(ORR)activity of carbonized ZIF-8(CZ)and its Fe-doped derivatives,CZ-A(doped with ammonium iron(II)sulphate)and CZ-B(doped with iron(II)acetate),were examined in both acidic(0.5 M H_(2)SO_...The oxygen reduction reaction(ORR)activity of carbonized ZIF-8(CZ)and its Fe-doped derivatives,CZ-A(doped with ammonium iron(II)sulphate)and CZ-B(doped with iron(II)acetate),were examined in both acidic(0.5 M H_(2)SO_(4))and basic(0.1 M KOH)electrolytes using a rotating disk electrode setup.These data show that the ORR activity of the Fe-doped catalysts is higher than that of pure CZ,with a higher activity in basic than acidic electrolyte.Extensive materials characterization highlights important differences in the sample crystallinity,morphology,porosity,and chemical composition as a function of the deployed precursor.The performance of the prepared catalysts is also impacted by the Fe precursor selection,highlighting the importance of such synthetic parameters in controlling the density and identify of Fe-Nx active sites.These results demonstrate the potential application of Fe-doped carbonized ZIF-8 catalysts for the ORR in basic electrolyte and offer important knowledge for the future design of non-precious metal fuel cell electrocatalysts.展开更多
The design and preparation of non-noble metal catalysts with high catalytic activity and robust stability are important in the research of metal-air batteries and fuel cells.Here,a three-dimensional(3D)hierarchically ...The design and preparation of non-noble metal catalysts with high catalytic activity and robust stability are important in the research of metal-air batteries and fuel cells.Here,a three-dimensional(3D)hierarchically ordered porous carbon nanomaterial was conveniently synthesized with zeolite-imidazole framework(ZIF-8)carbonization using the silica-template method and carbon nanotube(CNT)growth.The addition of an iron source endows the porous mFeNCCNT with Fe-based nanoparticles and abundant atomically dispersive Fe-Nx sites from its nitrogen-incorporated graphitic carbon matrix.As a result,the 3D porous structure reduces the charge transport resistance,and the iron and nitrogen codoped carbon exhibits excellent catalytic activity for oxygen reduction reaction(ORR)similar to that of commercial Pt/C.Meanwhile,the interwoven CNTs obtained under urea catalysis further shorten the ion and electron diffusion pathway.Experimental and theoretical analyses revealed that the optimized mFeNC-CNT has a high ORR activity with a half-wave potential of 0.908 V and a large open-circuit voltage(1.556 V)when applied on zinc-air batteries.This work provides a promising strategy for the rational design and facile synthesis of high-performing non-noble metal-based electrocatalysts for energy storage,conversion,and transport applications.展开更多
For catalytic materials,the characteristics of one-dimension and hollowness are the promotion factors for their full presentation of catalytic activity,and through a template-as sis ted method,both above superiorities...For catalytic materials,the characteristics of one-dimension and hollowness are the promotion factors for their full presentation of catalytic activity,and through a template-as sis ted method,both above superiorities can be fused simultaneously.Here,we proposed a novel strategy inspired by Pearson's principle with Cu_(2)O wires as templates,and prepared FeOOH hollow tubes,which covered by FeOOH scales.When applied as oxygen evolution reaction(OER)catalyst,the FeOOH scaly hollow tubes(FeOOH SHTs)showed outstanding catalytic activity with a low overpotential of 245 mV to drive a current density of10 mA·cm^(-2),excellent kinetics manifesting as a low Tafel slope of 46.9 mV·dec^(-1),and robust stability.This work provides a new synthesis strategy for an ideal OER catalyst,FeOOH,with high inherent activity and enhances the feasibility to broaden the design ideas of transition metalbased catalysts.展开更多
Isolated active metal atoms anchored on nitrogen-doped carbon matrix have been developed as the efficient catalyst for accelerating sluggish reaction kinetics of oxygen reduction reaction(ORR).The facile rational stru...Isolated active metal atoms anchored on nitrogen-doped carbon matrix have been developed as the efficient catalyst for accelerating sluggish reaction kinetics of oxygen reduction reaction(ORR).The facile rational structure engineering with abundant isolated active metal atoms is highly desirable but challenging.Herein,we demonstrate that atomically dispersed Fe sites(Fe-N4 moieties)on the hierarchical porous nitrogen-doped carbon matrix(Fe-SA-PNC)for high ORR activity can be achieved by a dual-template assisted strategy.By thermal decomposition of NH_(4)Cl template,the nitrogen-doped carbon matrix is generated based on the interaction with carbon precursor of citric acid.Meanwhile,the introduction of NaCl template facilitates the formation of hierarchical porous structures,which enable more active sites exposed and improve the mass transfer.Interestingly,the dual-template strategy can inhibit the formation of iron carbide nanoparticles(NPs)by generating porous structures and avoiding of the rapid loss of nitrogen during pyrolysis.The as-made Fe-SA-PNC catalysts with well-defined Fe-N_(4)active sites exhibit highly efficient ORR activity with a half-wave potential of 0.838 V versus the reversible hydrogen electrode,as well as good stability and methanol tolerance,outperforming the commercial Pt/C.The zinc-air battery(ZAB)constructed by Fe-SA-PNC also shows a higher peak power density and specific discharging capacity than that of Pt-based ZAB.The present work provides the facile strategy for tailoring nitrogen doping and porous structures simultaneously to prevent the formation NPs for achieving the well-dispersed and accessible single-atom active sites,paving a new way to design efficient electrocatalysts for ORR in fuel cells.展开更多
Electrochemical nitrogen reduction reaction(NRR)paves a new way to cost-efficient production of ammonia,but is still challenging in the sluggish kinetics caused by hydrogen evolution reaction competition and chemical ...Electrochemical nitrogen reduction reaction(NRR)paves a new way to cost-efficient production of ammonia,but is still challenging in the sluggish kinetics caused by hydrogen evolution reaction competition and chemical inertness of N≡N bond.Herein,we report a“dual-site”strategy for boosting NRR performance.A high-performance catalyst is successfully constructed by anchoring isolated Fe and Mo atoms on hierarchical N doped carbon nanotubes through a facile self-sacrificing template route,which exhibits a remarkably improved NH3 yield rate of 26.8μg·h^(−1)·mg with 11.8%Faradaic efficiency,which is 2.5 and 1.6 times larger than those of Fe/NC and Mo/NC.The enhancement can be attributed to the unique hierarchical structure that profits from the contact of electrode and electrolyte,thus improving the mass and electron transport.More importantly,the in situ Fourier transform infrared spectroscopy(in situ FTIR)result firmly demonstrates the crucial role of the coupling of Fe and Mo atoms,which can efficiently boost the generation and transmission of*N2Hy intermediates,leading to an accelerated reaction rate.展开更多
The sluggish reaction kinetics of oxygen evolution reaction(OER)has largely lowered the efficiency of electrochemical water splitting.Ir represents one of the state-of-the-art electrocatalysts for promoting OER especi...The sluggish reaction kinetics of oxygen evolution reaction(OER)has largely lowered the efficiency of electrochemical water splitting.Ir represents one of the state-of-the-art electrocatalysts for promoting OER especially in acidic electrolytes.However,it remains a formidable challenge to synthesize high-quality one-dimensional(1D)Ir-based nanostructures for improved electrocatalytic performance.Herein,a template-assisted synthesis method is reported wherein 1D porous Ir-Te nanowires(Ir-Te NWs)are synthesized with Te NWs serving as the template.The Ir-Te NWs exhibit highly enhanced OER performance compared to commercial IrO_(2) and Ir/C.In detail,the overpotentials to reach 10 mA cm^(-2) are 248 and 284 mV in 1 M KOH and 0.5 M H2S04,respectively,much lower than those of commercial catalysts.The Ir-Te NWs also show smaller Tafel slopes than commercial IrO_(2) and Ir/C,signifying faster reaction kinetics.Besides,much more durable OER activity can be maintained for Ir-Te NWs with negligible decay during 25 and 20 h stability tests in 1 M KOH and 0.5 M H_(2)SO_(4),respectively.Further analysis indicates that the significantly improved OER performance of Ir-Te NWs could be ascribed to the larger electrochemical surface area and smaller electrical resistance.More significantly,the templated synthesis of Ir-Te NWs can be facilely extended to the fabrication of other metal-Te NWs including Ru-Te,Rh-Te and Pt-Te NWs.The design and synthesis of 1D metal-based NWs in this work provide important inspiration for the synthesis of diversified 1D metallic nanostructures with distinctly enhanced catalytic performance and beyond.展开更多
As sustainable energy becomes a major concern for modern society,renewable and clean energy systems need highly active,stable,and low-cost catalysts for the oxygen evolution reaction(OER).Mesoporous materials offer an...As sustainable energy becomes a major concern for modern society,renewable and clean energy systems need highly active,stable,and low-cost catalysts for the oxygen evolution reaction(OER).Mesoporous materials offer an attractive route for generating efficient electrocatalysts with high mass transport capabilities.Herein,we report an efficient hard templating pathway to design and synthesize three-dimensional(3-D)mesoporous ternary nickel iron nitride(Ni3FeN).The as-synthesized electrocatalyst shows good OER performance in an alkaline solution with low overpotential(259 mV)and a small Tafel slope(54 mV dec?1),giving superior performance to IrO2 and RuO2 catalysts.The highly active contact area,the hierarchical porosity,and the synergistic effect of bimetal atoms contributed to the improved electrocatalytic performance toward OER.In a practical rechargeable Zn–air battery,mesoporous Ni3FeN is also shown to deliver a lower charging voltage and longer lifetime than RuO2.This work opens up a new promising approach to synthesize active OER electrocatalysts for energy-related devices.展开更多
Transition metal compound(TMC)/carbon hybrids,as prospering electrocatalyst,have attracted great attention in the field of oxygen reduction reaction(ORR).Their morphology,structure and composition often play a crucial...Transition metal compound(TMC)/carbon hybrids,as prospering electrocatalyst,have attracted great attention in the field of oxygen reduction reaction(ORR).Their morphology,structure and composition often play a crucial role in determining the ORR performance.In this work,we for the first time report the successful fabrication of porous core-shell Fe_(1-x)S@N,S co-doped carbon(Fe_(1-x)S@NSC-t,t represents etching time)by a novel in-situ self-template induced strategy using Fe3O4 nanospheres and pyrrole as sacrificial self-template.The post-polymerization of pyrrole can be accomplished by the Fe^(3+)released through the etching of Fe_(3)O_(4) by HCl acid.Thus,the etching time has a significant effect on the morphology,structure,composition a nd ORR performance of Fe_(1-x)S@NSC-t.Based on the cha racterizations,we find Fe_(1-x)S@NSC-24 can realize effective and balanced combination of Fe_(1-x)S and NSC,possessing porous core-shell architecture,optimized structure defect,specific surface area and doped heteroatoms configurations(especially for pyridinic N,graphitic N and Fe-N structure).These features thus lead to outstanding catalytic activity and cycling stability towards ORR.Our work provides a good guidance on the design of TMC/carbon-based electrodes with unique stable morphology and optimized structure and composition.展开更多
Using Cu(II) as the template, a complex {[Cu2L2(H2O)2]·4H2O}n (L = N-acetoxyl- picolinamide) has been successfully synthesized and characterized by single-crystal X-ray diffrac- tion. The crystal is of monoclin...Using Cu(II) as the template, a complex {[Cu2L2(H2O)2]·4H2O}n (L = N-acetoxyl- picolinamide) has been successfully synthesized and characterized by single-crystal X-ray diffrac- tion. The crystal is of monoclinic, space group C2/c, with a = 24.144(5), b = 7.1622(14), c = 17.283(4) ?, C16H24Cu2N4O12, Mr = 591.47, β = 131.73(3)o, V = 2230.3(8) ?3, Z = 4, Dc = 1.761 g/cm3, F(000) = 1208, μ = 1.978 mm?1, R = 0.0400 and wR = 0.1099. The copper (II) ion is five- coordinated with a distorted square pyramidal geometry. The complex can be viewed as a one- dimensional chain structure by carboxylic bridges among copper atoms. In the complex there exist hydrogen bonding interactions to stabilize the structure.展开更多
The rod-shaped form of crystalline β-FeOOH (akaganeite) was prepared by the template-free hydrothermal method with urea as the homogeneous precipitant. X-ray diffraction, field-emission scanning electron microscope a...The rod-shaped form of crystalline β-FeOOH (akaganeite) was prepared by the template-free hydrothermal method with urea as the homogeneous precipitant. X-ray diffraction, field-emission scanning electron microscope and Fourier transform infrared spectrum were used to characterize the resulting products. The degradation of methyl orange (MO) was studied using the prepared nanostructure materials in a photo-Fenton-like process. MO degradation was effectively achieved by hydroxyl radicals that were generated in the heterogeneous catalysis process. Specific surface area of the prepared β-FeOOH was an important factor affecting the efficiency of MO degradation, which depended on the synthesis conditions such as the reaction temperature, the initial concentration of urea and FeCl3.6H2O as well as the n(urea)/n(Fe3+) ratio. The photodegradation efficiencies slightly decreased with the increase of initial pH in the range of 4.5 - 9.5, which indicated the prepared β-FeOOH catalyst can well overcome the drawback of a narrow pH range of homogeneous Fenton reaction. β-FeOOH catalysts loading and H2O2 concentration also play important effect on the degradation efficiency of MO. The prepared β-FeOOH showed good ability of reuse for multiple trials.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51972349,U1801255,and 51972350)the National Natural Science Foundation of Guangdong Province(No.2022A1515011596).T。
文摘The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction(HER)depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface.Here,a self-standing porous tubular Mott-Schottky electrocatalyst is constructed by a self-template etching strategy,where amorphous WO_(x)(a-WO_(x))nano-matrix connects Co nanoparticles.This novel“Janus”electrocatalyst maximizes the Mott-Schottky effect by not only providing a highly exposed micro interface,but also simultaneously accelerating the water dissociation and optimizing the hydrogen desorption process.Experimental findings and theoretical calculations reveal that Co/a-WO_(x)Mott-Schottky heterointerface triggers the electron redistribution and a build-in electric field,which can not only optimize the adsorption energy of the reaction intermediates,but also facilitate the charge transfer.Thus,Co/a-WO_(x)requires an overpotential of only 36.3 mV at 10 mA·cm^(−2)and shows a small Tafel slope of 53.9 mV·dec^(−1)as well as an excellent 200-h long-term stability.This work provides a novel design strategy for maximizing the Mott-Schottky effect on promoting alkaline HER.
文摘The oxygen reduction reaction(ORR)activity of carbonized ZIF-8(CZ)and its Fe-doped derivatives,CZ-A(doped with ammonium iron(II)sulphate)and CZ-B(doped with iron(II)acetate),were examined in both acidic(0.5 M H_(2)SO_(4))and basic(0.1 M KOH)electrolytes using a rotating disk electrode setup.These data show that the ORR activity of the Fe-doped catalysts is higher than that of pure CZ,with a higher activity in basic than acidic electrolyte.Extensive materials characterization highlights important differences in the sample crystallinity,morphology,porosity,and chemical composition as a function of the deployed precursor.The performance of the prepared catalysts is also impacted by the Fe precursor selection,highlighting the importance of such synthetic parameters in controlling the density and identify of Fe-Nx active sites.These results demonstrate the potential application of Fe-doped carbonized ZIF-8 catalysts for the ORR in basic electrolyte and offer important knowledge for the future design of non-precious metal fuel cell electrocatalysts.
基金financially supported by the Basic Science and Technology Research Project of Wenzhou,Zhejiang Province(G20190007 and ZG2017027)the BUCT-WZU Joint Fund(KH2012031)the State Key Laboratory of Structural Chemistry,Chinese Academy of Sciences(20190008)。
文摘The design and preparation of non-noble metal catalysts with high catalytic activity and robust stability are important in the research of metal-air batteries and fuel cells.Here,a three-dimensional(3D)hierarchically ordered porous carbon nanomaterial was conveniently synthesized with zeolite-imidazole framework(ZIF-8)carbonization using the silica-template method and carbon nanotube(CNT)growth.The addition of an iron source endows the porous mFeNCCNT with Fe-based nanoparticles and abundant atomically dispersive Fe-Nx sites from its nitrogen-incorporated graphitic carbon matrix.As a result,the 3D porous structure reduces the charge transport resistance,and the iron and nitrogen codoped carbon exhibits excellent catalytic activity for oxygen reduction reaction(ORR)similar to that of commercial Pt/C.Meanwhile,the interwoven CNTs obtained under urea catalysis further shorten the ion and electron diffusion pathway.Experimental and theoretical analyses revealed that the optimized mFeNC-CNT has a high ORR activity with a half-wave potential of 0.908 V and a large open-circuit voltage(1.556 V)when applied on zinc-air batteries.This work provides a promising strategy for the rational design and facile synthesis of high-performing non-noble metal-based electrocatalysts for energy storage,conversion,and transport applications.
基金financially supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(Nos.12004031,12034002 and 51971025)+3 种基金Beijing Natural Science Foundation(No.2212034)Foshan Talents Special Foundation(No.BKBS202003)the Scientific and Technological Innovation Foundation of Foshan(No.BK22BE005)Foshan Science and Technology Innovation Project(No.2018IT100363)。
文摘For catalytic materials,the characteristics of one-dimension and hollowness are the promotion factors for their full presentation of catalytic activity,and through a template-as sis ted method,both above superiorities can be fused simultaneously.Here,we proposed a novel strategy inspired by Pearson's principle with Cu_(2)O wires as templates,and prepared FeOOH hollow tubes,which covered by FeOOH scales.When applied as oxygen evolution reaction(OER)catalyst,the FeOOH scaly hollow tubes(FeOOH SHTs)showed outstanding catalytic activity with a low overpotential of 245 mV to drive a current density of10 mA·cm^(-2),excellent kinetics manifesting as a low Tafel slope of 46.9 mV·dec^(-1),and robust stability.This work provides a new synthesis strategy for an ideal OER catalyst,FeOOH,with high inherent activity and enhances the feasibility to broaden the design ideas of transition metalbased catalysts.
基金funded by the Youth Innovation Promotion Association CAS(No.202055)the National Key R&D Program of China(Nos.2019YFA0709202 and 2020YFB2009004).
文摘Isolated active metal atoms anchored on nitrogen-doped carbon matrix have been developed as the efficient catalyst for accelerating sluggish reaction kinetics of oxygen reduction reaction(ORR).The facile rational structure engineering with abundant isolated active metal atoms is highly desirable but challenging.Herein,we demonstrate that atomically dispersed Fe sites(Fe-N4 moieties)on the hierarchical porous nitrogen-doped carbon matrix(Fe-SA-PNC)for high ORR activity can be achieved by a dual-template assisted strategy.By thermal decomposition of NH_(4)Cl template,the nitrogen-doped carbon matrix is generated based on the interaction with carbon precursor of citric acid.Meanwhile,the introduction of NaCl template facilitates the formation of hierarchical porous structures,which enable more active sites exposed and improve the mass transfer.Interestingly,the dual-template strategy can inhibit the formation of iron carbide nanoparticles(NPs)by generating porous structures and avoiding of the rapid loss of nitrogen during pyrolysis.The as-made Fe-SA-PNC catalysts with well-defined Fe-N_(4)active sites exhibit highly efficient ORR activity with a half-wave potential of 0.838 V versus the reversible hydrogen electrode,as well as good stability and methanol tolerance,outperforming the commercial Pt/C.The zinc-air battery(ZAB)constructed by Fe-SA-PNC also shows a higher peak power density and specific discharging capacity than that of Pt-based ZAB.The present work provides the facile strategy for tailoring nitrogen doping and porous structures simultaneously to prevent the formation NPs for achieving the well-dispersed and accessible single-atom active sites,paving a new way to design efficient electrocatalysts for ORR in fuel cells.
基金supported by the financial aid from National Science and Technology Major Project of China(No.2021YFB3500700)National Natural Science Foundation of China(Nos.22020102003,22025506,and 22271274)+2 种基金Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-3-3)K.C.Wong Education Foundation(No.GJTD-2018-09)Innovation and Entrepreneurship Program of Jilin Province(No.E2390202).
文摘Electrochemical nitrogen reduction reaction(NRR)paves a new way to cost-efficient production of ammonia,but is still challenging in the sluggish kinetics caused by hydrogen evolution reaction competition and chemical inertness of N≡N bond.Herein,we report a“dual-site”strategy for boosting NRR performance.A high-performance catalyst is successfully constructed by anchoring isolated Fe and Mo atoms on hierarchical N doped carbon nanotubes through a facile self-sacrificing template route,which exhibits a remarkably improved NH3 yield rate of 26.8μg·h^(−1)·mg with 11.8%Faradaic efficiency,which is 2.5 and 1.6 times larger than those of Fe/NC and Mo/NC.The enhancement can be attributed to the unique hierarchical structure that profits from the contact of electrode and electrolyte,thus improving the mass and electron transport.More importantly,the in situ Fourier transform infrared spectroscopy(in situ FTIR)result firmly demonstrates the crucial role of the coupling of Fe and Mo atoms,which can efficiently boost the generation and transmission of*N2Hy intermediates,leading to an accelerated reaction rate.
基金supported by the National Key R&D Program of China(Nos.2017YFA0208200 and 2016YFA0204100)the National Natural Science Foundation of China(No.22025108)。
文摘The sluggish reaction kinetics of oxygen evolution reaction(OER)has largely lowered the efficiency of electrochemical water splitting.Ir represents one of the state-of-the-art electrocatalysts for promoting OER especially in acidic electrolytes.However,it remains a formidable challenge to synthesize high-quality one-dimensional(1D)Ir-based nanostructures for improved electrocatalytic performance.Herein,a template-assisted synthesis method is reported wherein 1D porous Ir-Te nanowires(Ir-Te NWs)are synthesized with Te NWs serving as the template.The Ir-Te NWs exhibit highly enhanced OER performance compared to commercial IrO_(2) and Ir/C.In detail,the overpotentials to reach 10 mA cm^(-2) are 248 and 284 mV in 1 M KOH and 0.5 M H2S04,respectively,much lower than those of commercial catalysts.The Ir-Te NWs also show smaller Tafel slopes than commercial IrO_(2) and Ir/C,signifying faster reaction kinetics.Besides,much more durable OER activity can be maintained for Ir-Te NWs with negligible decay during 25 and 20 h stability tests in 1 M KOH and 0.5 M H_(2)SO_(4),respectively.Further analysis indicates that the significantly improved OER performance of Ir-Te NWs could be ascribed to the larger electrochemical surface area and smaller electrical resistance.More significantly,the templated synthesis of Ir-Te NWs can be facilely extended to the fabrication of other metal-Te NWs including Ru-Te,Rh-Te and Pt-Te NWs.The design and synthesis of 1D metal-based NWs in this work provide important inspiration for the synthesis of diversified 1D metallic nanostructures with distinctly enhanced catalytic performance and beyond.
基金supported by Chinese Academy of Sciences(Grant No.2018PS0011)100 Talent Plan of Chinese Academy of Sciences+4 种基金Natural Science Foundation of China(Grant No.61971405)the Department of Science and Technology(GoI)for support through the Project Nos.DST FILE NO.YSS/2015/001712,DST 11-IFAPH-07 and DST FILE NO.DST/TMD/SERI/HUBthe financial support from Equipment Research Program(Grant No.6140721050215)the Ontario Ministry of Research and Innovation(ER15-11-123)the Natural Science and Engineering Council of Canada(RGPIN-2019-05994).
文摘As sustainable energy becomes a major concern for modern society,renewable and clean energy systems need highly active,stable,and low-cost catalysts for the oxygen evolution reaction(OER).Mesoporous materials offer an attractive route for generating efficient electrocatalysts with high mass transport capabilities.Herein,we report an efficient hard templating pathway to design and synthesize three-dimensional(3-D)mesoporous ternary nickel iron nitride(Ni3FeN).The as-synthesized electrocatalyst shows good OER performance in an alkaline solution with low overpotential(259 mV)and a small Tafel slope(54 mV dec?1),giving superior performance to IrO2 and RuO2 catalysts.The highly active contact area,the hierarchical porosity,and the synergistic effect of bimetal atoms contributed to the improved electrocatalytic performance toward OER.In a practical rechargeable Zn–air battery,mesoporous Ni3FeN is also shown to deliver a lower charging voltage and longer lifetime than RuO2.This work opens up a new promising approach to synthesize active OER electrocatalysts for energy-related devices.
基金financially supported by the National Natural Science Foundation of China(Nos.51804116,51772092,51972109)Hunan Provincial Natural Science Foundation of China(Nos.2018JJ3207,2017JJ2103,2019JJ40102,2019JJ50205,2018JJ2149)+1 种基金China Scholarship Councilthe Scientific Research Fund of Hunan Provincial Education Department,China(Nos.18B346,18A315,18B347,19A205)。
文摘Transition metal compound(TMC)/carbon hybrids,as prospering electrocatalyst,have attracted great attention in the field of oxygen reduction reaction(ORR).Their morphology,structure and composition often play a crucial role in determining the ORR performance.In this work,we for the first time report the successful fabrication of porous core-shell Fe_(1-x)S@N,S co-doped carbon(Fe_(1-x)S@NSC-t,t represents etching time)by a novel in-situ self-template induced strategy using Fe3O4 nanospheres and pyrrole as sacrificial self-template.The post-polymerization of pyrrole can be accomplished by the Fe^(3+)released through the etching of Fe_(3)O_(4) by HCl acid.Thus,the etching time has a significant effect on the morphology,structure,composition a nd ORR performance of Fe_(1-x)S@NSC-t.Based on the cha racterizations,we find Fe_(1-x)S@NSC-24 can realize effective and balanced combination of Fe_(1-x)S and NSC,possessing porous core-shell architecture,optimized structure defect,specific surface area and doped heteroatoms configurations(especially for pyridinic N,graphitic N and Fe-N structure).These features thus lead to outstanding catalytic activity and cycling stability towards ORR.Our work provides a good guidance on the design of TMC/carbon-based electrodes with unique stable morphology and optimized structure and composition.
文摘Using Cu(II) as the template, a complex {[Cu2L2(H2O)2]·4H2O}n (L = N-acetoxyl- picolinamide) has been successfully synthesized and characterized by single-crystal X-ray diffrac- tion. The crystal is of monoclinic, space group C2/c, with a = 24.144(5), b = 7.1622(14), c = 17.283(4) ?, C16H24Cu2N4O12, Mr = 591.47, β = 131.73(3)o, V = 2230.3(8) ?3, Z = 4, Dc = 1.761 g/cm3, F(000) = 1208, μ = 1.978 mm?1, R = 0.0400 and wR = 0.1099. The copper (II) ion is five- coordinated with a distorted square pyramidal geometry. The complex can be viewed as a one- dimensional chain structure by carboxylic bridges among copper atoms. In the complex there exist hydrogen bonding interactions to stabilize the structure.
文摘The rod-shaped form of crystalline β-FeOOH (akaganeite) was prepared by the template-free hydrothermal method with urea as the homogeneous precipitant. X-ray diffraction, field-emission scanning electron microscope and Fourier transform infrared spectrum were used to characterize the resulting products. The degradation of methyl orange (MO) was studied using the prepared nanostructure materials in a photo-Fenton-like process. MO degradation was effectively achieved by hydroxyl radicals that were generated in the heterogeneous catalysis process. Specific surface area of the prepared β-FeOOH was an important factor affecting the efficiency of MO degradation, which depended on the synthesis conditions such as the reaction temperature, the initial concentration of urea and FeCl3.6H2O as well as the n(urea)/n(Fe3+) ratio. The photodegradation efficiencies slightly decreased with the increase of initial pH in the range of 4.5 - 9.5, which indicated the prepared β-FeOOH catalyst can well overcome the drawback of a narrow pH range of homogeneous Fenton reaction. β-FeOOH catalysts loading and H2O2 concentration also play important effect on the degradation efficiency of MO. The prepared β-FeOOH showed good ability of reuse for multiple trials.
