The eight heteropoly complexes M4H2[PW9（NbO2）3O37]·xH2O和M4-mHm[PW11（NbO2）O39]·xH2O(M=Me4N+（TMA）,Bu4N+（TBA）,Et4N+（TEA）,He4H+（THA）were synthesized and characterized by IR,UV spectrometry,polarogra...The eight heteropoly complexes M4H2[PW9（NbO2）3O37]·xH2O和M4-mHm[PW11（NbO2）O39]·xH2O(M=Me4N+（TMA）,Bu4N+（TBA）,Et4N+（TEA）,He4H+（THA）were synthesized and characterized by IR,UV spectrometry,polarography and 183W NMR spectra.The experimantal results indicated that they were all the Keggin structure and the reduced electric potential of the complexes arised over-0.3 with entering of NbO2 groups.Experiments on oxidation of maleic acid into tartaric acid showed that the complexes containing peroxo ions exhibited higher catalytic activity than those without peroxo ions.The catalytic activity of heteropoly complexes with（NbO2）3 was higher than that of heteropoly complexes with（NbO2）.展开更多
By taking tetragonal tungsten bronze(TTB)phase Nb_(18)W_(16)O_(93)as an example,an improved solid-state sintering method at lower temperature of 1000℃for 36 h was proposed via applying nanoscale raw materials.XRD,SEM...By taking tetragonal tungsten bronze(TTB)phase Nb_(18)W_(16)O_(93)as an example,an improved solid-state sintering method at lower temperature of 1000℃for 36 h was proposed via applying nanoscale raw materials.XRD,SEM and XPS confirm that the expected sample was produced.GITT results show that the lithium-ion diffusion coefficient of Nb_(18)W_(16)O_(93)(10−12 cm^(2)/s)is higher than that of the conventional titanium-based anode,ensuring a relatively superior electrochemical performance.The lithium-ion diffusion mechanism was thoroughly revealed by using density functional theory simulation.There are three diffusion paths in TTB phase,among which the interlayer diffusion with the smallest diffusion barrier(0.46 eV)has more advantages than other typical anodes(such as graphite,0.56 eV).The relatively smaller lithium-ion diffusion barrier makes TTB phase Nb_(18)W_(16)O_(93)become a potential highspecific-power anode material.展开更多
文摘The eight heteropoly complexes M4H2[PW9（NbO2）3O37]·xH2O和M4-mHm[PW11（NbO2）O39]·xH2O(M=Me4N+（TMA）,Bu4N+（TBA）,Et4N+（TEA）,He4H+（THA）were synthesized and characterized by IR,UV spectrometry,polarography and 183W NMR spectra.The experimantal results indicated that they were all the Keggin structure and the reduced electric potential of the complexes arised over-0.3 with entering of NbO2 groups.Experiments on oxidation of maleic acid into tartaric acid showed that the complexes containing peroxo ions exhibited higher catalytic activity than those without peroxo ions.The catalytic activity of heteropoly complexes with（NbO2）3 was higher than that of heteropoly complexes with（NbO2）.
基金the Key R&D Program of Shaanxi Province,China(No.2019ZDLGY04-05)the Natural Science Foundation of Shaanxi Province,China(No.2019JLZ-01)+1 种基金the Fundamental Research Funds for the Central Universities of China(Nos.19GH020302,3102019JC005,3102021ZD0401,3102021TS0406)the Science,Technology,and Innovation Commission of Shenzhen Municipality,China(No.JCYJ20180508151856806).
文摘By taking tetragonal tungsten bronze(TTB)phase Nb_(18)W_(16)O_(93)as an example,an improved solid-state sintering method at lower temperature of 1000℃for 36 h was proposed via applying nanoscale raw materials.XRD,SEM and XPS confirm that the expected sample was produced.GITT results show that the lithium-ion diffusion coefficient of Nb_(18)W_(16)O_(93)(10−12 cm^(2)/s)is higher than that of the conventional titanium-based anode,ensuring a relatively superior electrochemical performance.The lithium-ion diffusion mechanism was thoroughly revealed by using density functional theory simulation.There are three diffusion paths in TTB phase,among which the interlayer diffusion with the smallest diffusion barrier(0.46 eV)has more advantages than other typical anodes(such as graphite,0.56 eV).The relatively smaller lithium-ion diffusion barrier makes TTB phase Nb_(18)W_(16)O_(93)become a potential highspecific-power anode material.
