Cation vacancies can bring numerous surprising characters due to its multifarious electron and orbit distribution.In this work,d-MnO_(2) with alkali-ion(K,Na,Li)associated manganese(Mn)vacancies is fabricated by a sim...Cation vacancies can bring numerous surprising characters due to its multifarious electron and orbit distribution.In this work,d-MnO_(2) with alkali-ion(K,Na,Li)associated manganese(Mn)vacancies is fabricated by a simple hydrothermal reaction,and the correlation between their electronic structure and pseudocapacitance are systematically investigated.FESEM/TEM images have shown that the morphology of MnO_(2) is obviously changed after the introducing of cation vacancies.The position of alkali-ion in MnO_(2) structure can be controlled by adjusting the ion concentration.XRD patterns and Raman spectra demonstrate that the alkali-ion is embedded in Mn vacancies at low concentration,while entered the interlayer of MnO_(2) at high concentration.The existence of Mn vacancies will resulting in the distortion of neighboring atoms,leading to the electronic delocalization,and thus enhancing the conductivity,pseudocapacitance and rate capability of MnO_(2).Accordingly,the specific capacitances of optimized 0.4 KMO,0.4 NaMO and 0.4 LiMO samples are enhanced about 1.9,1.6 and 1.6 times compared to pure MnO_(2).Meanwhile,the rate performance has also been improved about 76%,46%and 42%,respectively.Theoretical calculations further confirm that the Mn vacancies can generate additional occupancy states and cause an increase in carrier concentration,which will improve the conductivity and further boost the pseudocapacitance of MnO_(2).This result open up a promising approach to explore active and durable electrode materials.展开更多
A saccharide fluorescent receptor based on 1,1'-binaphthol was developed.The boronic acids groups are di-rectly attached to the 3,3'-positions of BINOL which acted as probes to saccharides.The methyl protected...A saccharide fluorescent receptor based on 1,1'-binaphthol was developed.The boronic acids groups are di-rectly attached to the 3,3'-positions of BINOL which acted as probes to saccharides.The methyl protected receptor R1 showed better response to D-fructose compared to other saccharides in the fluorescence quenching experiment.To improve the selectivity of D-glucose,the triethylene glycol protected receptor R2 was developed.Receptor R2 has a better water-solubility than R1 that can be applied in completely aqueous environment.With receptor R2,D-glucose has a different response to other saccharides that can be useful for the distinction of D-glucose.展开更多
基金supported by Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ18E030005,LY18E060005,LY19E020006,LY18E020007National Natural Science Foundation of China(No.51902301)。
文摘Cation vacancies can bring numerous surprising characters due to its multifarious electron and orbit distribution.In this work,d-MnO_(2) with alkali-ion(K,Na,Li)associated manganese(Mn)vacancies is fabricated by a simple hydrothermal reaction,and the correlation between their electronic structure and pseudocapacitance are systematically investigated.FESEM/TEM images have shown that the morphology of MnO_(2) is obviously changed after the introducing of cation vacancies.The position of alkali-ion in MnO_(2) structure can be controlled by adjusting the ion concentration.XRD patterns and Raman spectra demonstrate that the alkali-ion is embedded in Mn vacancies at low concentration,while entered the interlayer of MnO_(2) at high concentration.The existence of Mn vacancies will resulting in the distortion of neighboring atoms,leading to the electronic delocalization,and thus enhancing the conductivity,pseudocapacitance and rate capability of MnO_(2).Accordingly,the specific capacitances of optimized 0.4 KMO,0.4 NaMO and 0.4 LiMO samples are enhanced about 1.9,1.6 and 1.6 times compared to pure MnO_(2).Meanwhile,the rate performance has also been improved about 76%,46%and 42%,respectively.Theoretical calculations further confirm that the Mn vacancies can generate additional occupancy states and cause an increase in carrier concentration,which will improve the conductivity and further boost the pseudocapacitance of MnO_(2).This result open up a promising approach to explore active and durable electrode materials.
基金supported by the National Program on Key Basic Research Project of China (973 Program,Nos.2012CB720603 and 2013CB328900)the National Science Foundation of China (Nos.21232005,21321061,J1310008 and J1103315)the Specialized Research Fund for the Doctoral Program of Higher Education in China (No.20120181130006).
文摘A saccharide fluorescent receptor based on 1,1'-binaphthol was developed.The boronic acids groups are di-rectly attached to the 3,3'-positions of BINOL which acted as probes to saccharides.The methyl protected receptor R1 showed better response to D-fructose compared to other saccharides in the fluorescence quenching experiment.To improve the selectivity of D-glucose,the triethylene glycol protected receptor R2 was developed.Receptor R2 has a better water-solubility than R1 that can be applied in completely aqueous environment.With receptor R2,D-glucose has a different response to other saccharides that can be useful for the distinction of D-glucose.
