Metal-N_(4)(M-N_(4))macrocyclic complexes are interesting electrocatalysts due to their well-defined structures and rich molecular tuning.Among them,metal phthalocyanines have been widely studied for the carbon dioxid...Metal-N_(4)(M-N_(4))macrocyclic complexes are interesting electrocatalysts due to their well-defined structures and rich molecular tuning.Among them,metal phthalocyanines have been widely studied for the carbon dioxide reduction reaction(CO_(2)RR)in heterogeneous systems and demonstrated good electrocatalytic performance.However,other complexes like metal corroles and metal porphyrins are much less explored,and often show inferior performances.In this study,three cobalt macrocyclic complexes,cobalt phthalocyanine,cobalt meso-tetraphenylporphyrin,and cobalt meso-triphenylcorrole(CoPc,CoTPP and CoTPC)are investigated in heterogeneous electrocatalysis of CO_(2)RR.Although CoPc/carbon nanotube(CNT)hybrid exhibits high electrocatalytic activity,CNT hybridization does not work for CoTPC and CoTPP that hold weak interactions with CNTs.By the drop-dry method with a high molecular loading of 5.4×10^(–7) mol cm^(–2),CoTPC and CoTPP could deliver appreciable electrode activities.Poly(4-vinylpyridine)(PVP)introduction is further demonstrated as a facile method to afford enhanced activities for CoTPP at low molecular loadings through enhancing molecule-substrate interactions.The partial current density of carbon monoxide for CoTPP+CNT/PVP is around 8 times higher than the sample without PVP at–0.67 V versus reversible hydrogen electrode.This work provides solutions to enhance the electrode activities of molecular electrocatalysts with weak substrate interactions in heterogeneous systems.展开更多
A spheroidal Al_3(Zr,Sc) precipitate with a double-shell structure, comprising a Sc-enriched core enveloped by a Zr-enriched inner shell and a Sc-enriched outer shell(～9 nm in thickness), appears in an Al-0.2 Zr-0.1 ...A spheroidal Al_3(Zr,Sc) precipitate with a double-shell structure, comprising a Sc-enriched core enveloped by a Zr-enriched inner shell and a Sc-enriched outer shell(～9 nm in thickness), appears in an Al-0.2 Zr-0.1 Sc alloy cable after thermomechanical treatment. The average diameter of the spheroidal Al_3(Zr,Sc) precipitate is approximately 80 nm. The double-shelled Al_3(Zr,Sc) precipitate presents three different interfaces and is semi-coherent with the Al matrix. Atom probe tomography(APT) analyses further show that the outer shell of Al_3(Zr,Sc) precipitate is Sc element enrichment. The electrical conductivity of Al-0.2 Zr-0.1 Sc alloy cable increases by 6.5 MS/m within the aging time from 0.2 to 100 h at 350 ℃, with double-shelled Al_3(Zr,Sc)precipitate.展开更多
Grains with size of 4.5—20.5μm were studied for their corrosion behavior and electrochemical performance in a Mg-3 Al-5 Pb-1 Ga-Y sacrificial anode using immersion testing,electrochemical measurements and microstruc...Grains with size of 4.5—20.5μm were studied for their corrosion behavior and electrochemical performance in a Mg-3 Al-5 Pb-1 Ga-Y sacrificial anode using immersion testing,electrochemical measurements and microstructure analysis.The results show that fine-grained microstructure has higher chemical activity and more negative discharge potentials than coarse-grained samples.The sample with the smallest average grain size of 4.5μm exhibits corrosion current density of 7.473×10-5 A/cm2,and work potentials of-1.721 V at current density of 10 mA/cm2.The density of grain boundaries and LAGBs increases with grain refinement,which leads to higher rates of dissolution and diffusion for the atoms.The secondary phases promote the occurrence of corrosion and improve the chemical activity of alloy due to their higher potential than the substrate.Higher corrosion rate and discharge activity are directly attributed to the higher density of grain boundaries and LAGBs,as well as the secondary phase.展开更多
To investigate the effects of apple polyphenols on ACE2 and its antibody binding, computer simulation and experiments in vitro were conducted. The results of molecular docking and molecular dynamics showed that apple ...To investigate the effects of apple polyphenols on ACE2 and its antibody binding, computer simulation and experiments in vitro were conducted. The results of molecular docking and molecular dynamics showed that apple polyphenols had a good binding effect on RBD and RBD-ACE2 complex. Fluorescence analysis exhibited that the three main apple polyphenols had a fluorescence quenching effect on the ACE2 antibodies, and the quenching mechanism was static. The results of the circular dichroism experiment suggested that apple polyphenols could change the secondary structure of the ACE2 antibodies. Western blot results displayed that apple polyphenols inhibited the binding of ACE2 and its antibodies. This study confirmed that apple polyphenols could bind ACE2 antibodies in vitro. Therefore, it is speculated that apple polyphenols have similar effects on a class of proteins with similar ACE2 recognition sites, which may potentially inhibit viral protein and ACE2 recognition, thus preventing viruses from entering host cells.展开更多
文摘Metal-N_(4)(M-N_(4))macrocyclic complexes are interesting electrocatalysts due to their well-defined structures and rich molecular tuning.Among them,metal phthalocyanines have been widely studied for the carbon dioxide reduction reaction(CO_(2)RR)in heterogeneous systems and demonstrated good electrocatalytic performance.However,other complexes like metal corroles and metal porphyrins are much less explored,and often show inferior performances.In this study,three cobalt macrocyclic complexes,cobalt phthalocyanine,cobalt meso-tetraphenylporphyrin,and cobalt meso-triphenylcorrole(CoPc,CoTPP and CoTPC)are investigated in heterogeneous electrocatalysis of CO_(2)RR.Although CoPc/carbon nanotube(CNT)hybrid exhibits high electrocatalytic activity,CNT hybridization does not work for CoTPC and CoTPP that hold weak interactions with CNTs.By the drop-dry method with a high molecular loading of 5.4×10^(–7) mol cm^(–2),CoTPC and CoTPP could deliver appreciable electrode activities.Poly(4-vinylpyridine)(PVP)introduction is further demonstrated as a facile method to afford enhanced activities for CoTPP at low molecular loadings through enhancing molecule-substrate interactions.The partial current density of carbon monoxide for CoTPP+CNT/PVP is around 8 times higher than the sample without PVP at–0.67 V versus reversible hydrogen electrode.This work provides solutions to enhance the electrode activities of molecular electrocatalysts with weak substrate interactions in heterogeneous systems.
基金Project supported by the 2011 Program of the Ministry of Education in China(043010100)
文摘A spheroidal Al_3(Zr,Sc) precipitate with a double-shell structure, comprising a Sc-enriched core enveloped by a Zr-enriched inner shell and a Sc-enriched outer shell(～9 nm in thickness), appears in an Al-0.2 Zr-0.1 Sc alloy cable after thermomechanical treatment. The average diameter of the spheroidal Al_3(Zr,Sc) precipitate is approximately 80 nm. The double-shelled Al_3(Zr,Sc) precipitate presents three different interfaces and is semi-coherent with the Al matrix. Atom probe tomography(APT) analyses further show that the outer shell of Al_3(Zr,Sc) precipitate is Sc element enrichment. The electrical conductivity of Al-0.2 Zr-0.1 Sc alloy cable increases by 6.5 MS/m within the aging time from 0.2 to 100 h at 350 ℃, with double-shelled Al_3(Zr,Sc)precipitate.
基金Project supported by the 2011 Program of the Ministry of Education in China(043010100,51701039)
文摘Grains with size of 4.5—20.5μm were studied for their corrosion behavior and electrochemical performance in a Mg-3 Al-5 Pb-1 Ga-Y sacrificial anode using immersion testing,electrochemical measurements and microstructure analysis.The results show that fine-grained microstructure has higher chemical activity and more negative discharge potentials than coarse-grained samples.The sample with the smallest average grain size of 4.5μm exhibits corrosion current density of 7.473×10-5 A/cm2,and work potentials of-1.721 V at current density of 10 mA/cm2.The density of grain boundaries and LAGBs increases with grain refinement,which leads to higher rates of dissolution and diffusion for the atoms.The secondary phases promote the occurrence of corrosion and improve the chemical activity of alloy due to their higher potential than the substrate.Higher corrosion rate and discharge activity are directly attributed to the higher density of grain boundaries and LAGBs,as well as the secondary phase.
基金supported by the National Natural Science Foundation of China 501(No.32172270).
文摘To investigate the effects of apple polyphenols on ACE2 and its antibody binding, computer simulation and experiments in vitro were conducted. The results of molecular docking and molecular dynamics showed that apple polyphenols had a good binding effect on RBD and RBD-ACE2 complex. Fluorescence analysis exhibited that the three main apple polyphenols had a fluorescence quenching effect on the ACE2 antibodies, and the quenching mechanism was static. The results of the circular dichroism experiment suggested that apple polyphenols could change the secondary structure of the ACE2 antibodies. Western blot results displayed that apple polyphenols inhibited the binding of ACE2 and its antibodies. This study confirmed that apple polyphenols could bind ACE2 antibodies in vitro. Therefore, it is speculated that apple polyphenols have similar effects on a class of proteins with similar ACE2 recognition sites, which may potentially inhibit viral protein and ACE2 recognition, thus preventing viruses from entering host cells.
