This work is devoted to the development of a low cost dimensionally stable anode with high oxygen evolution catalytic activity for practical applications.For this purpose,a Ti/SnO_(x)/MnO_(2) anode was fabricated thro...This work is devoted to the development of a low cost dimensionally stable anode with high oxygen evolution catalytic activity for practical applications.For this purpose,a Ti/SnO_(x)/MnO_(2) anode was fabricated through an innovative strategy involving Sn electrodeposition,oxidation,and MnO_(2)-layer preparation.The structure of the anode was characterized,and the oxygen evolution performance was evaluated in a H_(2)SO_(4) solution.The results show that compared with the Ti/SnO_(2)/MnO_(2) anode prepared by the conventional brushing-annealing process,the Ti/SnO_(x)/MnO_(2) anode fabricated through the innovative procedure exhibits a lower oxygen evolution potential and a nearly 40%longer accelerated lifespan.The superior oxygen evolution performance of the Ti/SnO_(x)/MnO_(2) anode is attributed to the distinctive SnO_(x) intermediate layer fabricated through Sn electrodeposition followed by oxidation,which indicates the great potential of the anode as a dimensionally stable anode for metal electrowinning and hydrogen production by electrolysis,etc.展开更多
The preparation of bifunctional catalysts for oxygen reduction(ORR)and oxygen evolution(OER)is crucial for Zn-air batteries.Here,we report a La doped CoFe_(2)O_(4)spinel catalyst supported on threedimensional graphene...The preparation of bifunctional catalysts for oxygen reduction(ORR)and oxygen evolution(OER)is crucial for Zn-air batteries.Here,we report a La doped CoFe_(2)O_(4)spinel catalyst supported on threedimensional graphene(3D-G),where La can facilitate electron transfer from Co to Fe,leading to increased electron cloud density in Fe and improved catalytic performance.The redshift of the G peak in the Raman spectra indicates the interaction between theπbond of 3D-G and d orbitals in La_(0.2)CoFe_(1.8)O_(4).La_(0.2)CoFe_(1.8)/3D-G exhibits superior ORR performance(E_(1/2)=0.86 V vs.RHE)and OER performance(E_(j=10)=1.55 V vs.RHE)to CoFe_(2)O_(4)/3D-G(E_(1/2)=0.831 V vs.RHE,E_(j=10)=1.603 V vs.RHE).Furthermore,it demonstrates excellent bifunctional oxygen catalytic performance while maintaining high power density and stability in liquid zinc-air batteries(ZABs)and flexible ZABs(F-ZABs).This work presents a viable strategy for utilizing rare earth element doped spinels to enhance oxygen catalyst and ZABs performance.展开更多
Chemical looping dry reforming（CLDR） is an innovative technology for CO2 utilization using the chemical looping principle.The CLDR process consists of three stages,i.e.CH4 reduction,CO2 reforming,and air oxidation.S...Chemical looping dry reforming（CLDR） is an innovative technology for CO2 utilization using the chemical looping principle.The CLDR process consists of three stages,i.e.CH4 reduction,CO2 reforming,and air oxidation.Spinel nickel ferrite（NiFe2O4） was prepared and its multi-cycle performance as an oxygen carrier for CLDR was experimentally investigated.X-ray diffraction（XRD） and Laser Raman spectroscopy showed that a pure spinel crystalline phase（NiFe2O4） was obtained by a parallel flow co-precipitating method.NiFe2O4was reduced into Fe-Ni alloy and wustite（FexO） during the CH4 reduction process.Subsequent oxidation of the reduced oxygen carrier was performed with CO2 as an oxidant to form an intermediate state：a mixture of spinel Ni（1-x）Fe（2＋x）O4,Fe（2＋y）O4 and metallic Ni.And CO was generated in parallel during this stage.Approximate 185 mL of CO was generated for 1 g spinel NiFe2O4 in a single cycle.The intermediate oxygen carrier was fully oxidized in the air oxidation stage to form a mixture of Ni（1＋x）Fe（2-x）O4 and Fe2O3.Although the original state of oxygen carrier（NiFe2O4） was not fully regenerated and agglomeration was observed,a good recyclability was shown in 10 successive redox cycles.展开更多
To solve the slow dynamics of catalytic oxygen reaction energy devices,a facile method was developed for the synthesis of methylene alcohol terminated poly(1,4-phenyldiimine)porphyrin cobalt(MPImPorCo),which was synth...To solve the slow dynamics of catalytic oxygen reaction energy devices,a facile method was developed for the synthesis of methylene alcohol terminated poly(1,4-phenyldiimine)porphyrin cobalt(MPImPorCo),which was synthesized by RuCl3 catalyzed redox reaction of meso-5,10,15,20-tetra(4-nitrophenyl)porphyrin cobalt(TNO2PorCo)and 1,4-phenyldimethanol.M-PImPorCo is a fully conjugated covalent organic framework(COF)with high thermal and chemical stability.COFs with different edge groups were synthesized to compare the effect of different groups(–CH_(2)–OH and–NO_(2))on catalytic bifunctional oxygen reaction activity.C=N as nitrogen-rich environment of M-PImPorCo leads to the protonation process of oxygen catalysis and reduces the energy barrier of adsorption in the oxygen intermediate.C=N and–CH_(2)–OH form an“electron pump”structure to deliver electrons to the Co–N4 site in M-PImPorCo,and theπ–πinteraction between M-PImPorCo and three-dimensional graphene(3D-G)can further enrich the electron cloud density of Co–N4 sites.M-PImPorCo/3D-G has remarkable oxygen catalytic performance,with a half-wave potential(E_(1/2))of 0.91 V vs.reversible hydrogen electrode(RHE).M-PImPorCo/3D-G has low potential(Ej=10 is 1.49 V vs.RHE)at a current density of 10 mA·cm^(-2).It exhibits a good bifunctional catalytic performance(potential difference(ΔE)=0.58 V).The smaller charge–discharge band gap of zinc-air batteries(ZABs)and flexible ZABs(F-ZABs)equipped with M-PImPorCo/3D-G suggests the potential for catalytic oxygen reaction bifunctional applications.This work provides a new idea for the synthesis of Schiff-base porphyrin-based COF catalyst and its potential application to oxygen reaction catalytic energy storage devices.展开更多
The scalable preparation of multi-functional three-dimensional （3D） carbon nanotubes and graphene （CNTs-G） hybrids via a well-controlled route is urgently required and challenging. Herein, an easily operated, oxal...The scalable preparation of multi-functional three-dimensional （3D） carbon nanotubes and graphene （CNTs-G） hybrids via a well-controlled route is urgently required and challenging. Herein, an easily operated, oxalic acid-assisted method was developed for the in situ fabrication of a 3D lasagna-like Fe-N-doped CNTs-G framework （LMFC） from a precursor designed at the molecular level. The well-organized architecture of LMFC was constructed by multi-dimensionally interconnected graphene and CNTs which derived from porous graphene sheets, to form a fundamentally robust and hierarchical porous structure, as well as favorable conductive networks. The impressive oxygen reduction reaction （ORR） performances in both alkaline and acidic conditions helped confirm the significance of this technically favorable morphological structure. This product was also the subject of research for the exploration of decisive effects on the performance of ORR catalysts with reasonable control variables. The present work further advances the construction of novel 3D carbon architectures via practical and economic routes.展开更多
Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have ...Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.展开更多
文摘This work is devoted to the development of a low cost dimensionally stable anode with high oxygen evolution catalytic activity for practical applications.For this purpose,a Ti/SnO_(x)/MnO_(2) anode was fabricated through an innovative strategy involving Sn electrodeposition,oxidation,and MnO_(2)-layer preparation.The structure of the anode was characterized,and the oxygen evolution performance was evaluated in a H_(2)SO_(4) solution.The results show that compared with the Ti/SnO_(2)/MnO_(2) anode prepared by the conventional brushing-annealing process,the Ti/SnO_(x)/MnO_(2) anode fabricated through the innovative procedure exhibits a lower oxygen evolution potential and a nearly 40%longer accelerated lifespan.The superior oxygen evolution performance of the Ti/SnO_(x)/MnO_(2) anode is attributed to the distinctive SnO_(x) intermediate layer fabricated through Sn electrodeposition followed by oxidation,which indicates the great potential of the anode as a dimensionally stable anode for metal electrowinning and hydrogen production by electrolysis,etc.
基金financially supported by the National Natural Science Foundation of China(22172093 and 21776167)the Natural Science Foundation of Shandong Province,China(ZR2023MB061).
文摘The preparation of bifunctional catalysts for oxygen reduction(ORR)and oxygen evolution(OER)is crucial for Zn-air batteries.Here,we report a La doped CoFe_(2)O_(4)spinel catalyst supported on threedimensional graphene(3D-G),where La can facilitate electron transfer from Co to Fe,leading to increased electron cloud density in Fe and improved catalytic performance.The redshift of the G peak in the Raman spectra indicates the interaction between theπbond of 3D-G and d orbitals in La_(0.2)CoFe_(1.8)O_(4).La_(0.2)CoFe_(1.8)/3D-G exhibits superior ORR performance(E_(1/2)=0.86 V vs.RHE)and OER performance(E_(j=10)=1.55 V vs.RHE)to CoFe_(2)O_(4)/3D-G(E_(1/2)=0.831 V vs.RHE,E_(j=10)=1.603 V vs.RHE).Furthermore,it demonstrates excellent bifunctional oxygen catalytic performance while maintaining high power density and stability in liquid zinc-air batteries(ZABs)and flexible ZABs(F-ZABs).This work presents a viable strategy for utilizing rare earth element doped spinels to enhance oxygen catalyst and ZABs performance.
基金the financial support by the National Natural Science Foundation of China(51406214 and51406208)supported by the Natural science Foundation of Guangdong Province(2015A030313719)the Science&Technology Research Project of Guangdong Province(2013B050800008)
文摘Chemical looping dry reforming（CLDR） is an innovative technology for CO2 utilization using the chemical looping principle.The CLDR process consists of three stages,i.e.CH4 reduction,CO2 reforming,and air oxidation.Spinel nickel ferrite（NiFe2O4） was prepared and its multi-cycle performance as an oxygen carrier for CLDR was experimentally investigated.X-ray diffraction（XRD） and Laser Raman spectroscopy showed that a pure spinel crystalline phase（NiFe2O4） was obtained by a parallel flow co-precipitating method.NiFe2O4was reduced into Fe-Ni alloy and wustite（FexO） during the CH4 reduction process.Subsequent oxidation of the reduced oxygen carrier was performed with CO2 as an oxidant to form an intermediate state：a mixture of spinel Ni（1-x）Fe（2＋x）O4,Fe（2＋y）O4 and metallic Ni.And CO was generated in parallel during this stage.Approximate 185 mL of CO was generated for 1 g spinel NiFe2O4 in a single cycle.The intermediate oxygen carrier was fully oxidized in the air oxidation stage to form a mixture of Ni（1＋x）Fe（2-x）O4 and Fe2O3.Although the original state of oxygen carrier（NiFe2O4） was not fully regenerated and agglomeration was observed,a good recyclability was shown in 10 successive redox cycles.
基金supported by the National Natural Science Foundation of China(Nos.22172093 and 21776167)the Natural Science Foundation of Shandong Province,China(No.ZR2023MB061).
文摘To solve the slow dynamics of catalytic oxygen reaction energy devices,a facile method was developed for the synthesis of methylene alcohol terminated poly(1,4-phenyldiimine)porphyrin cobalt(MPImPorCo),which was synthesized by RuCl3 catalyzed redox reaction of meso-5,10,15,20-tetra(4-nitrophenyl)porphyrin cobalt(TNO2PorCo)and 1,4-phenyldimethanol.M-PImPorCo is a fully conjugated covalent organic framework(COF)with high thermal and chemical stability.COFs with different edge groups were synthesized to compare the effect of different groups(–CH_(2)–OH and–NO_(2))on catalytic bifunctional oxygen reaction activity.C=N as nitrogen-rich environment of M-PImPorCo leads to the protonation process of oxygen catalysis and reduces the energy barrier of adsorption in the oxygen intermediate.C=N and–CH_(2)–OH form an“electron pump”structure to deliver electrons to the Co–N4 site in M-PImPorCo,and theπ–πinteraction between M-PImPorCo and three-dimensional graphene(3D-G)can further enrich the electron cloud density of Co–N4 sites.M-PImPorCo/3D-G has remarkable oxygen catalytic performance,with a half-wave potential(E_(1/2))of 0.91 V vs.reversible hydrogen electrode(RHE).M-PImPorCo/3D-G has low potential(Ej=10 is 1.49 V vs.RHE)at a current density of 10 mA·cm^(-2).It exhibits a good bifunctional catalytic performance(potential difference(ΔE)=0.58 V).The smaller charge–discharge band gap of zinc-air batteries(ZABs)and flexible ZABs(F-ZABs)equipped with M-PImPorCo/3D-G suggests the potential for catalytic oxygen reaction bifunctional applications.This work provides a new idea for the synthesis of Schiff-base porphyrin-based COF catalyst and its potential application to oxygen reaction catalytic energy storage devices.
基金Acknowledgements Financial supports from the National Natural Science Foundation of China （Nos. 21622308, 91534114, and 21376208）, the the China Ministry of Science and Technology （No. 2016YFA0202900）, the Fundamental Research Funds for the Central Universities （No. 2016FZA3006）, and the Partner Group Program of the Zhejiang University and the Max-Planck Society are appreciated greatly.
文摘The scalable preparation of multi-functional three-dimensional （3D） carbon nanotubes and graphene （CNTs-G） hybrids via a well-controlled route is urgently required and challenging. Herein, an easily operated, oxalic acid-assisted method was developed for the in situ fabrication of a 3D lasagna-like Fe-N-doped CNTs-G framework （LMFC） from a precursor designed at the molecular level. The well-organized architecture of LMFC was constructed by multi-dimensionally interconnected graphene and CNTs which derived from porous graphene sheets, to form a fundamentally robust and hierarchical porous structure, as well as favorable conductive networks. The impressive oxygen reduction reaction （ORR） performances in both alkaline and acidic conditions helped confirm the significance of this technically favorable morphological structure. This product was also the subject of research for the exploration of decisive effects on the performance of ORR catalysts with reasonable control variables. The present work further advances the construction of novel 3D carbon architectures via practical and economic routes.
基金supported by the National Key R&D Program of China(No.2021YFA1501101)the National Nature Science Foundation of China(Nos.21862011,21771156,and 51864024)+4 种基金Yunnan province(No.2019FI003)the Shenzhen Knowledge Innovation Program(Basic Research,No.JCYJ20190808181205752)the Research Grants Council(RGC)of the Hong Kong Special Administrative Region,China(Project No.CityU 11206520)the National Natural Science Foundation of China/RGC Joint Research Scheme(No.N_PolyU502/21)the funding for Projects of Strategic Importance of The Hong Kong Polytechnic University(Project Code:1-ZE2V).
文摘Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.
