Electrochemical Scanning TUnneling Microscopy (ECSTM) has been extended to characterizc polycrystalline silver electrode surfaces in iodide solution. Potential-dependcnt ordered and disordered structures of the silver...Electrochemical Scanning TUnneling Microscopy (ECSTM) has been extended to characterizc polycrystalline silver electrode surfaces in iodide solution. Potential-dependcnt ordered and disordered structures of the silver electrode as well as the iodine adsorption layer have been obscrved to coexist on polycrystalline silver electrode surfaces, for the first time. A very special column arrangement of the iodine adsorption layer, similar to the so called "ndssing row" type of structure has been obseryed. Some columns of the iodine adsorption layer roll over from one place to another along with the time and changing potential. A proposed model has been given to better describe the structure. The highly corrugated and loose surface structure of the polycrystalline surface are responsible for this special phenomenon.展开更多
The adsorption of a variety of fullerenes (C60,C70,C86,Y@C82) on Au(111) electrode surfaces was comprehensively investigated in 0.1 M HClO4 by electrochemical scanning tunneling microscopy (ECSTM).In the ordered C60&#...The adsorption of a variety of fullerenes (C60,C70,C86,Y@C82) on Au(111) electrode surfaces was comprehensively investigated in 0.1 M HClO4 by electrochemical scanning tunneling microscopy (ECSTM).In the ordered C60's adlayer,C60 molecules formed either (2(1/3) × 2 3～(1/3))or "in-phase" structure.The high resolution STM image shows that the C60 cage is not simply round but shows a bifurcated feature.The adsorption orientation of C60 on Au(111) is tentatively suggested.In the ordered C70's adlayer,the perpendicular fullerene molecules are the main adsorption mode and form (2 3～(1/3) × 2 3～(1/3)) structure.However,for C86 and Y@C82,the ordered adlayer could not be obtained on Au(111) under the present condition.These differences may be due to the different molecular shapes and sizes,and the encapsulated metal atom which affects the lattice matches with the substrate.The adsorption of fullerene molecules on Au(111) from disorder to order could be tuned simply by steering the dimensional sizes or shapes of the fullerenes used.展开更多
A nanocrystalline coating of Cu-20Zr (in wt pct) was obtained on glass by magnetron sputtering. The corrosion behavior of the Cu-20Zr film in 0.001 mol/L HCI solution was investigated using potentiodynamic polarizatio...A nanocrystalline coating of Cu-20Zr (in wt pct) was obtained on glass by magnetron sputtering. The corrosion behavior of the Cu-20Zr film in 0.001 mol/L HCI solution was investigated using potentiodynamic polarization and in situ electrochemical scanning-tunneling-microscopy (ECSTM). Results demonstrated that the film exhibits active behavior. Microscopic pitting corrosion and tunneling are caused by localized electrodissolution of Zr atoms and the diffusion of Cu atoms at surface defects.展开更多
文摘Electrochemical Scanning TUnneling Microscopy (ECSTM) has been extended to characterizc polycrystalline silver electrode surfaces in iodide solution. Potential-dependcnt ordered and disordered structures of the silver electrode as well as the iodine adsorption layer have been obscrved to coexist on polycrystalline silver electrode surfaces, for the first time. A very special column arrangement of the iodine adsorption layer, similar to the so called "ndssing row" type of structure has been obseryed. Some columns of the iodine adsorption layer roll over from one place to another along with the time and changing potential. A proposed model has been given to better describe the structure. The highly corrugated and loose surface structure of the polycrystalline surface are responsible for this special phenomenon.
基金support from the Chinese Academy of Sciences (KZCX2-YW-QN407)the National Natural Science Foundation of China (20807049)+1 种基金the National Basic Research Program of China (2009CB421606)the Project-sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education
文摘The adsorption of a variety of fullerenes (C60,C70,C86,Y@C82) on Au(111) electrode surfaces was comprehensively investigated in 0.1 M HClO4 by electrochemical scanning tunneling microscopy (ECSTM).In the ordered C60's adlayer,C60 molecules formed either (2(1/3) × 2 3～(1/3))or "in-phase" structure.The high resolution STM image shows that the C60 cage is not simply round but shows a bifurcated feature.The adsorption orientation of C60 on Au(111) is tentatively suggested.In the ordered C70's adlayer,the perpendicular fullerene molecules are the main adsorption mode and form (2 3～(1/3) × 2 3～(1/3)) structure.However,for C86 and Y@C82,the ordered adlayer could not be obtained on Au(111) under the present condition.These differences may be due to the different molecular shapes and sizes,and the encapsulated metal atom which affects the lattice matches with the substrate.The adsorption of fullerene molecules on Au(111) from disorder to order could be tuned simply by steering the dimensional sizes or shapes of the fullerenes used.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China un-der contract No.50001013.
文摘A nanocrystalline coating of Cu-20Zr (in wt pct) was obtained on glass by magnetron sputtering. The corrosion behavior of the Cu-20Zr film in 0.001 mol/L HCI solution was investigated using potentiodynamic polarization and in situ electrochemical scanning-tunneling-microscopy (ECSTM). Results demonstrated that the film exhibits active behavior. Microscopic pitting corrosion and tunneling are caused by localized electrodissolution of Zr atoms and the diffusion of Cu atoms at surface defects.
基金Financial support from the National Natural Science Foundation of China(No.21872126)the Zhejiang Provincial Natural Science Foundation of China(No.LQ21B030010)。
