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Registro Completo |
Biblioteca(s): |
Embrapa Instrumentação. |
Data corrente: |
22/12/1999 |
Data da última atualização: |
22/12/1999 |
Autoria: |
ASSIS, O. B. G.; CRNKOVIC, F. C.; BERNARDES FILHO, R.; AVACA, L. A. |
Afiliação: |
EMBRAPA-CNPDIA; USP-IQSC. |
Título: |
Roughness assessment of Ni-Co spinel type oxide electrode by atomic force microscope. |
Ano de publicação: |
1997 |
Fonte/Imprenta: |
In: MEETING OF THE BRAZILIAN SOCIETY FOR ELECTRON MICROSCOPY, 16., 1997, CAXAMBU. Proceedings of the 16. Meeting of the Brazilian Society for Electron Microscopy. Caxambu: Brazilian Society for Electron Microscopy, 1997. p. 76-77. Acta Microscopica, v.6, Supplement A, September 1997. |
Idioma: |
Inglês |
Conteúdo: |
Spinel type oxides such as NiCO2O4, are of great interest for application in electrochemical industry specially as anodes for water electrolysis and the oxygen evolution reaction. The large electrocatalytic activity of these types of materials under potentiodynamic conditions results from mechanisms of ionic transference on the solid-liquid interface and are rather dependent on the real electrode area. An increase in the geometric surface outcome an increase in the current density enhancing thus the electrolysis reaction. The roughness factor in voltametric condition, is deduced from the electrochemical peak currents normalized with respect to a flat reference electrode, as the relation (Ic(flat/Ic(rough)). Since the electrolyte medium offers differences in the ionic conductivity, and bubbles can be generate and keep attached to the electrode's surface crevices, the estimation by this method is limited and validated only in a short range of experimental conditions.An reliable way to state relative irregularities in solid surfaces is by the generation of scanning atomic force microscope (AFM) images. The AFM allows the evaluation of the surface by a direct topography assessment. In this work, the roughness of a Ni-Co base oxide electrode is evaluated as an example of the potential of the atomic force microscopy in revealing subtle details of surface. This technique when associated with appropriated software analysis, presents large advantage over chemical or two-dimensional microscopy techniques. In Figure 1 is presented a random 50 x 50 micrometers area from a central region of a NiCo2O4 polished, flat like electrode, prepared as describe in reference 3. Three intermediates analytical lines at (A), (B) and (C) were traced and the surface profiles plotted in Figure 2. These cross-sectional plots presents the actual topography along the particular line scanned. As it is possible to compare, the topographies lines show shallow corrugation and blunts increasing from the top to the bottom regions of the figure. The standard roughness values presented in the boxes of Figure 2, means the linear measurements of the lines correspondent to the surface's lenghts, since the projected straight line are 50 micrometers lenght it is possible to evaluate a proportional increase of area from a flat surface. An other possible tools is the overall roughness mapping on the figure. That is performed by processing the data from the total of the lines scanned. For the scanned regions, the RMS area is found to be 1.87 times the projected one. In Figure 3 a three dimensional projection of the region is plotted. MenosSpinel type oxides such as NiCO2O4, are of great interest for application in electrochemical industry specially as anodes for water electrolysis and the oxygen evolution reaction. The large electrocatalytic activity of these types of materials under potentiodynamic conditions results from mechanisms of ionic transference on the solid-liquid interface and are rather dependent on the real electrode area. An increase in the geometric surface outcome an increase in the current density enhancing thus the electrolysis reaction. The roughness factor in voltametric condition, is deduced from the electrochemical peak currents normalized with respect to a flat reference electrode, as the relation (Ic(flat/Ic(rough)). Since the electrolyte medium offers differences in the ionic conductivity, and bubbles can be generate and keep attached to the electrode's surface crevices, the estimation by this method is limited and validated only in a short range of experimental conditions.An reliable way to state relative irregularities in solid surfaces is by the generation of scanning atomic force microscope (AFM) images. The AFM allows the evaluation of the surface by a direct topography assessment. In this work, the roughness of a Ni-Co base oxide electrode is evaluated as an example of the potential of the atomic force microscopy in revealing subtle details of surface. This technique when associated with appropriated software analysis, presents large advantage over chemical or two-dimensional m... Mostrar Tudo |
Palavras-Chave: |
AFM; Agricultural instrumentation; Congressos; EMBRAPA-CNPDIA; Instrumentacao agropecuaria; Microscopia de forca atomica; Technique; Tecnica. |
Thesaurus Nal: |
atomic force microscopy. |
Categoria do assunto: |
-- |
Marc: |
LEADER 03626naa a2200265 a 4500 001 1027137 005 1999-12-22 008 1997 bl --- 0-- u #d 100 1 $aASSIS, O. B. G. 245 $aRoughness assessment of Ni-Co spinel type oxide electrode by atomic force microscope. 260 $c1997 520 $aSpinel type oxides such as NiCO2O4, are of great interest for application in electrochemical industry specially as anodes for water electrolysis and the oxygen evolution reaction. The large electrocatalytic activity of these types of materials under potentiodynamic conditions results from mechanisms of ionic transference on the solid-liquid interface and are rather dependent on the real electrode area. An increase in the geometric surface outcome an increase in the current density enhancing thus the electrolysis reaction. The roughness factor in voltametric condition, is deduced from the electrochemical peak currents normalized with respect to a flat reference electrode, as the relation (Ic(flat/Ic(rough)). Since the electrolyte medium offers differences in the ionic conductivity, and bubbles can be generate and keep attached to the electrode's surface crevices, the estimation by this method is limited and validated only in a short range of experimental conditions.An reliable way to state relative irregularities in solid surfaces is by the generation of scanning atomic force microscope (AFM) images. The AFM allows the evaluation of the surface by a direct topography assessment. In this work, the roughness of a Ni-Co base oxide electrode is evaluated as an example of the potential of the atomic force microscopy in revealing subtle details of surface. This technique when associated with appropriated software analysis, presents large advantage over chemical or two-dimensional microscopy techniques. In Figure 1 is presented a random 50 x 50 micrometers area from a central region of a NiCo2O4 polished, flat like electrode, prepared as describe in reference 3. Three intermediates analytical lines at (A), (B) and (C) were traced and the surface profiles plotted in Figure 2. These cross-sectional plots presents the actual topography along the particular line scanned. As it is possible to compare, the topographies lines show shallow corrugation and blunts increasing from the top to the bottom regions of the figure. The standard roughness values presented in the boxes of Figure 2, means the linear measurements of the lines correspondent to the surface's lenghts, since the projected straight line are 50 micrometers lenght it is possible to evaluate a proportional increase of area from a flat surface. An other possible tools is the overall roughness mapping on the figure. That is performed by processing the data from the total of the lines scanned. For the scanned regions, the RMS area is found to be 1.87 times the projected one. In Figure 3 a three dimensional projection of the region is plotted. 650 $aatomic force microscopy 653 $aAFM 653 $aAgricultural instrumentation 653 $aCongressos 653 $aEMBRAPA-CNPDIA 653 $aInstrumentacao agropecuaria 653 $aMicroscopia de forca atomica 653 $aTechnique 653 $aTecnica 700 1 $aCRNKOVIC, F. C. 700 1 $aBERNARDES FILHO, R. 700 1 $aAVACA, L. A. 773 $tIn: MEETING OF THE BRAZILIAN SOCIETY FOR ELECTRON MICROSCOPY, 16., 1997, CAXAMBU. Proceedings of the 16. Meeting of the Brazilian Society for Electron Microscopy. Caxambu: Brazilian Society for Electron Microscopy, 1997. p. 76-77. Acta Microscopica$gv.6, Supplement A, September 1997.
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Embrapa Instrumentação (CNPDIA) |
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Registros recuperados : 36 | |
6. | | VAZ, C. M. P.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; CRESTANA, S. Adsorção do herbicida atrazina em diferentes solos. In: REUNIAO BRASILEIRA DE MANEJO E CONSERVACAO DO SOLO E DA AGUA: PEQUENA PROPRIEDADE X DESENVOLVIMENTO SUSTENTAVEL, 10., jul. 1994, Florianopolis, SC. Resumos... Florianopolis: Sociedade Brasileira de Ciencia do Solo, 1994. p.356-357. Ref.122.Biblioteca(s): Embrapa Instrumentação. |
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7. | | VAZ, C. M. P.; CRESTANA, S.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A. Adsorption isotherms for atrazine on soils measured by differential pulse polarography. Electroanalysis, Weinheim, v. 9, n. 12, p. 956-958, 1997.Biblioteca(s): Embrapa Instrumentação. |
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8. | | SIMÕES, M.; ASSIS, O. B. G.; AVACA, L. A.; BERNARDES-FILHO, R. Análise morfológica e do carácter passivador de revestimentos de SIO2 obtidos por sol-gel, sobre aços inoxidáveis sinterizados 304 e 316. In: CONGRESSO BRASILEIRO DE ANÁLISE TÉRMICA E CALORIMETRIA - CBECIMAT, 13., SEMINÁRIO DE MATERIAIS NO SETOR ELÉTRICO - SEMEL, 6., 1998, Curitiba. [Anais]: programa preliminar... Curitiba: LAC-TEC, 1998. p. 651-660, ref. ME CO 686. 1 CD-ROM.Biblioteca(s): Embrapa Instrumentação. |
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9. | | VAZ, C. M. P.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; CRESTANA, S. Analise de pesticidas por polarografia: determinacao de isotermas de adsorcao em solos. In: CONGRESSO BRASILEIRO DE CIENCIA DO SOLO: O SOLO NOS GRANDES DOMINIOS MORFOCLIMATICOS DO BRASIL E O DESENVOLVIMENTO SUSTENTADO, 25., jul. 1995, Vicosa, MG. Resumos expandidos... Vicosa: Universidade Federal de Vicosa, 1995. v.4 p.2393-2395. Ref.IX.39.Biblioteca(s): Embrapa Instrumentação. |
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12. | | VAZ, C. M. P.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; CRESTANA, S. Determinação de atrazina em solos por voltametria diferencial de pulso. In: CONGRESSO BRASILEIRO DE CIENCIA DO SOLO - CERRADOS: FRONTEIRA AGRICOLA NO SECULO XXI, 24., jul. 1993, Goiania, GO. Resumos... Goiania: Sociedade Brasileira de Ciencia do Solo, 1993. p.291-292. Ref.542.Biblioteca(s): Embrapa Instrumentação. |
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13. | | VAZ, C. M. P.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; CRESTANA, S. Método eletroquímico para a determinação analítica do herbicida atrazina. In: CONGRESSO IBEROAMERICANO DE ELECTROQUÍMICA, 11.; SIMPÓSIO BRASILEIRO DE ELETROQUÍMICA E ELETROANALÍTICA, 9., abr. 1994, Águas de Lindóia, SP. Resumos... São Paulo: Sociedade Brasileira de Química, 1994. p.527-529. Ref.III-26.Biblioteca(s): Embrapa Instrumentação. |
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14. | | ASSIS, O. B. G.; CRNKOVIC, F. C.; BERNARDES FILHO, R.; AVACA, L. A. Roughness assessment of Ni-Co spinel type oxide electrode by atomic force microscope. In: MEETING OF THE BRAZILIAN SOCIETY FOR ELECTRON MICROSCOPY, 16., 1997, CAXAMBU. Proceedings of the 16. Meeting of the Brazilian Society for Electron Microscopy. Caxambu: Brazilian Society for Electron Microscopy, 1997. p. 76-77. Acta Microscopica, v.6, Supplement A, September 1997.Biblioteca(s): Embrapa Instrumentação. |
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16. | | VAZ, C. M. P.; MASSAROPI, M. R. C.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; CRESTANA, S. Adsorption isotherms of atrazine and 2,4-D in soils using differential pulse polarography. In: IUPAC GARP WORKSHOP PN PESTICIDES: USES AND ENVIRONMENTAL SAFETY IN LATIN AMERICA, Oct. 1996, Sao Paulo, SP. Book of abstracts... Sao Paulo: Sociedade Brasileira de Quimica, 1996. p. 65. Ref.P-03.Biblioteca(s): Embrapa Instrumentação. |
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17. | | CRNKOVIC, F. C.; MACHADO, S. A. S.; AVACA, L. A.; BERNARDES FILHO, R.; ASSIS, O. B. G.; MASCARO, L. H. Análise microscópica da superfície de filmes de NiFeCo obtidos por eletrodeposição. In: CONGRESSO BRASILEIRO DE ANÁLISE TÉRMICA E CALORIMETRIA - CBECIMAT, 13., SEMINÁRIO DE MATERIAIS NO SETOR ELÉTRICO - SEMEL, 6., 1998, Curitiba. [Anais]: programa preliminar... Curitiba: LAC-TEC, 1998. p. 387-393, ref. ME CA 687. 1 CD-ROM.Biblioteca(s): Embrapa Instrumentação. |
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18. | | MACHADO, S. A. S.; VAZ, C. M. P.; CRESTANA, S.; MAZO, L. H.; MASSAROPPI, M. R. C.; AVACA, L. A. Análise de pesticidas por técnicas eletroanalíticas. In: SIMPOSIO NACIONAL DE INSTRUMENTACAO AGROPECUARIA, 1., 1996, Sao Carlos. Anais do I SIAGRO. Brasilia: EMBRAPA-SPI, 1997. p. 337-346.Biblioteca(s): Embrapa Instrumentação. |
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19. | | VAZ, C. M. P.; MASSAROPPI, M. R. C.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; CRESTANA, S. Determinação polarográfica de isotermas de adsorção do herbicida atrazina em solos. In: REUNIAO ANUAL DA SOCIEDADE BRASILEIRA DE QUIMICA, 17., maio 1994, Caxambu, MG. Livro de resumos... Sao Paulo: Sociedade Brasileira de Quimica, 1994. Nao-paginado. Ref.QA-123.Biblioteca(s): Embrapa Instrumentação. |
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20. | | MASSAROPPI, M. R. C.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; VAZ, C. M. P.; CRESTANA, S. Utilização da polarografia de pulso diferencial na determinação de isotermas de adsorção de freundlich do herbicida 2,4-d em solos. In: SIMPOSIO BRASILEIRO DE ELETROQUIMICA E ELETROANALITICA, 10., out. 1996, Sao Carlos, SP. Livro de resumos... Sao Carlos: UFSCar/USP, 1996. p. 137-139.Biblioteca(s): Embrapa Instrumentação. |
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Registros recuperados : 36 | |
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