In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBC...In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.展开更多
The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,pe...The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,peptide containing —SH and amino acid containing imidazolyl en- hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP is studied.展开更多
The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditi...The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditions.The photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 or SiO2@Fe3O4nanoparticles or coordinated with an axial azide ligand was also investigated.The results demonstrated that the photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 was higher than that loaded on SiO2@Fe3O4.The kinetic curves of RhB degradation in aqueous solutions at different pH indicated the pseudo first-order kinetics of the reaction.The highest degradation rate for CoPz（BuS）8 loaded Al2O3 at pH = 4 after 160 min was 84.6%.However,the advantages of easier separation and recycling as well as the ability to terminate the reaction at any time for the CoPz（BuS）8 loaded SiO2@Fe3O4 cannot be ignored.When electron-rich NaN3 was coordinated with CoPz（BuS）8 as an axial ligand and loaded on Al2O3,the resulting catalyst produced more active oxygen species such as O2^- and HO· to promote the quicker degradation of RhB than that by the other catalysts.For the N3-coordinated CoPz（BuS）8 loaded on Al2O3,the reactions at pH = 4 and 7 distinctly deviated from first-order kinetics,and the degradation rate reached 77.6%after 80 min at pH = 4.展开更多
In order to demonstrate the effect of the sixth axial ligand on the biological funtionof heme proteins, we have determined the formal potentials and electron transfer numbersof imidazole (Im), 1-methylimidazole (1-MeI...In order to demonstrate the effect of the sixth axial ligand on the biological funtionof heme proteins, we have determined the formal potentials and electron transfer numbersof imidazole (Im), 1-methylimidazole (1-MeIm) and 1-ethylimidazole (1-EtIm) complexes ofcytochrome c(cyt c) with an optically transparent thin-layer electrode.展开更多
In an effort to provide visualization and understanding to the electronic ‘‘push effect' of axial ligands on the catalytic activity of cobalt macrocyclic molecules, we design a simple model system involving an[5...In an effort to provide visualization and understanding to the electronic ‘‘push effect' of axial ligands on the catalytic activity of cobalt macrocyclic molecules, we design a simple model system involving an[5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin]cobalt(II)(TMMPCo) monolayer axially-coordinated on thiol ligand modified Au electrode and explore the activity of the axial-ligand coordinated TMPPCo toward oxygen reduction reaction(ORR) in acidic medium. Three different ligands, with a decreasing order of coordinating ability as: 4-mercaptopyridine(MPy) > 4-aminothiolphenol(APT) > 4-mercaptobenzonitrile(MBN) are used and a maximum difference in ORR onset potential of 80 mV is observed between the MPy(highest onset potential) and MBN systems(lowest onset potential). The ORR activity of TMPPCo increases with the increase in binding strength of the axial ligand. A detailed mechanism study reveals that ORR on the three ligand coordinated TMPPCo systems shares the same2-electron mechanism with H2 O2 as the terminal product. Theoretical calculation into the structure of the ligand coordinated cobalt porphyrins uncovers the variation in atomic charge of the Co(II) center and altered frontier molecular orbital distribution among the three ligand systems. Both properties have great influence on the back-bonding formation between the Co(II) center and O2 molecules, which has been suggested to be critical toward the O2 adsorption and subsequent activation process.展开更多
A series of 1D and 2D 1H NMR studies are presented, which aim at assigning the hyperfine shifted resonances of the heme and the spin systems of more than 20 amino acid side chains, and characterizing the heme and liga...A series of 1D and 2D 1H NMR studies are presented, which aim at assigning the hyperfine shifted resonances of the heme and the spin systems of more than 20 amino acid side chains, and characterizing the heme and ligand environment of the low spin imidazole complex of cytochrome c. Some details of the structure in the heme pocket of the cytochrome c-imidazole complex are shownqualitatively to have changed relatively to the native oxidized protein. The orientation of the coordinated imidazole is also determined based on the interpretation of a number of NOEs.展开更多
Electrocatalytic oxygen reduction and evolution reactions are involved in new energy conversion and storage technologies,such as various fuel cells and metal-air batteries and also water splitting devices[1,2].However...Electrocatalytic oxygen reduction and evolution reactions are involved in new energy conversion and storage technologies,such as various fuel cells and metal-air batteries and also water splitting devices[1,2].However,both reactions are very slow in kinetics,and thus catalysts are required[3,4].展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.2017R1D1A1B03032033 and 2020R1C1C1010386)“Leaders in INdustry-university Cooperation+”project supported by the Ministry of Education and National Research Foundation of Korea。
文摘In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.
文摘The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,peptide containing —SH and amino acid containing imidazolyl en- hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP is studied.
基金supported by National Natural Science Foundation of China (20977115, 21272281)Natural Science Foundation of Hubei Province (2014CFB919)the Science and Technology Plan Innovation Team of Wuhan City (2015070504020220)~~
文摘The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditions.The photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 or SiO2@Fe3O4nanoparticles or coordinated with an axial azide ligand was also investigated.The results demonstrated that the photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 was higher than that loaded on SiO2@Fe3O4.The kinetic curves of RhB degradation in aqueous solutions at different pH indicated the pseudo first-order kinetics of the reaction.The highest degradation rate for CoPz（BuS）8 loaded Al2O3 at pH = 4 after 160 min was 84.6%.However,the advantages of easier separation and recycling as well as the ability to terminate the reaction at any time for the CoPz（BuS）8 loaded SiO2@Fe3O4 cannot be ignored.When electron-rich NaN3 was coordinated with CoPz（BuS）8 as an axial ligand and loaded on Al2O3,the resulting catalyst produced more active oxygen species such as O2^- and HO· to promote the quicker degradation of RhB than that by the other catalysts.For the N3-coordinated CoPz（BuS）8 loaded on Al2O3,the reactions at pH = 4 and 7 distinctly deviated from first-order kinetics,and the degradation rate reached 77.6%after 80 min at pH = 4.
基金Project supported by the National Natural Science Foundation of China.
文摘In order to demonstrate the effect of the sixth axial ligand on the biological funtionof heme proteins, we have determined the formal potentials and electron transfer numbersof imidazole (Im), 1-methylimidazole (1-MeIm) and 1-ethylimidazole (1-EtIm) complexes ofcytochrome c(cyt c) with an optically transparent thin-layer electrode.
基金supported by the National Key Research and Development Program of China (2017YFA0206500)the National Natural Science Foundation of China (21635004, 21675079)
文摘In an effort to provide visualization and understanding to the electronic ‘‘push effect' of axial ligands on the catalytic activity of cobalt macrocyclic molecules, we design a simple model system involving an[5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin]cobalt(II)(TMMPCo) monolayer axially-coordinated on thiol ligand modified Au electrode and explore the activity of the axial-ligand coordinated TMPPCo toward oxygen reduction reaction(ORR) in acidic medium. Three different ligands, with a decreasing order of coordinating ability as: 4-mercaptopyridine(MPy) > 4-aminothiolphenol(APT) > 4-mercaptobenzonitrile(MBN) are used and a maximum difference in ORR onset potential of 80 mV is observed between the MPy(highest onset potential) and MBN systems(lowest onset potential). The ORR activity of TMPPCo increases with the increase in binding strength of the axial ligand. A detailed mechanism study reveals that ORR on the three ligand coordinated TMPPCo systems shares the same2-electron mechanism with H2 O2 as the terminal product. Theoretical calculation into the structure of the ligand coordinated cobalt porphyrins uncovers the variation in atomic charge of the Co(II) center and altered frontier molecular orbital distribution among the three ligand systems. Both properties have great influence on the back-bonding formation between the Co(II) center and O2 molecules, which has been suggested to be critical toward the O2 adsorption and subsequent activation process.
基金Project supported by the National Natural Science Foundaion of China.
文摘A series of 1D and 2D 1H NMR studies are presented, which aim at assigning the hyperfine shifted resonances of the heme and the spin systems of more than 20 amino acid side chains, and characterizing the heme and ligand environment of the low spin imidazole complex of cytochrome c. Some details of the structure in the heme pocket of the cytochrome c-imidazole complex are shownqualitatively to have changed relatively to the native oxidized protein. The orientation of the coordinated imidazole is also determined based on the interpretation of a number of NOEs.
基金the support from the National Natural Science Foundation of China(21773146,22171176 and 22102092)the Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University+2 种基金the Research Funds of Shaanxi Normal Universitythe Fundamental Research Funds for the Central Universitiesthe NRF of Korea(NRF-2021R1A3B1076539 and NRF-2020R1I1A1A01074630)。
文摘Electrocatalytic oxygen reduction and evolution reactions are involved in new energy conversion and storage technologies,such as various fuel cells and metal-air batteries and also water splitting devices[1,2].However,both reactions are very slow in kinetics,and thus catalysts are required[3,4].
