Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>

The electrical characterization of catalysts composed of layered manganese oxide in the form of birnessite supported on &#947;-Al<sub>2</sub>O<sub>3</sub>, which have been successfully used in the combustion of soot, is presented. The results indicate that the electrical...

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Main Authors: Nayda P. Arias, María E. Becerra, Oscar Giraldo
Format: Article
Language:English
Published: MDPI AG 2019-08-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/24/16/2984
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author Nayda P. Arias
María E. Becerra
Oscar Giraldo
author_facet Nayda P. Arias
María E. Becerra
Oscar Giraldo
author_sort Nayda P. Arias
collection DOAJ
description The electrical characterization of catalysts composed of layered manganese oxide in the form of birnessite supported on &#947;-Al<sub>2</sub>O<sub>3</sub>, which have been successfully used in the combustion of soot, is presented. The results indicate that the electrical conduction and ion conduction processes are influenced by the amount of the active phase. There was also evidence of Grotthuss-type proton conductivity favored by the presence of surface water on the exposed alumina surface. The above is supported by the porous nature of the catalyst in which the surface area varied between 125.2 &#177; 1.2 and 159.0 &#177; 1.1 m<sup>2</sup>/g, evidencing changes in the alumina surface. The conductivity, determined from measurements of impedance spectroscopy, at low frequency showed changes associated with the amount of the active phase. The values ranged from 2.61 &#215; 10<sup>&#8722;8</sup> &#177; 2.1 &#215; 10<sup>&#8722;9</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup> (pure alumina) to 7.33 &#215; 10<sup>&#8722;8</sup> &#177; 5.9 &#215; 10<sup>&#8722;9</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup>, 7.21 &#215; 10<sup>&#8722;8</sup> &#177; 5.8 &#215; 10<sup>&#8722;9</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup> and 4.51 &#215; 10<sup>&#8722;7</sup> &#177; 3.6 &#215; 10<sup>&#8722;8</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup> at room temperature for catalysts with nominal active phase contents of 5.0, 10.0 and 20.0%, respectively. Such results indicate that it is possible to modulate the electrical properties with variations in the synthesis parameters.
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spelling doaj.art-c365258ef6ed40339e1401942aa69eef2022-12-22T01:53:02ZengMDPI AGMolecules1420-30492019-08-012416298410.3390/molecules24162984molecules24162984Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>Nayda P. Arias0María E. Becerra1Oscar Giraldo2Grupo de Investigación en Procesos Químicos, Catalíticos y Biotecnológicos, Universidad Nacional de Colombia-Sede Manizales, Kilometro 9 vía al aeropuerto, La Nubia, 170003 Manizales, ColombiaGrupo de Investigación en Procesos Químicos, Catalíticos y Biotecnológicos, Universidad Nacional de Colombia-Sede Manizales, Kilometro 9 vía al aeropuerto, La Nubia, 170003 Manizales, ColombiaGrupo de Investigación en Procesos Químicos, Catalíticos y Biotecnológicos, Universidad Nacional de Colombia-Sede Manizales, Kilometro 9 vía al aeropuerto, La Nubia, 170003 Manizales, ColombiaThe electrical characterization of catalysts composed of layered manganese oxide in the form of birnessite supported on &#947;-Al<sub>2</sub>O<sub>3</sub>, which have been successfully used in the combustion of soot, is presented. The results indicate that the electrical conduction and ion conduction processes are influenced by the amount of the active phase. There was also evidence of Grotthuss-type proton conductivity favored by the presence of surface water on the exposed alumina surface. The above is supported by the porous nature of the catalyst in which the surface area varied between 125.2 &#177; 1.2 and 159.0 &#177; 1.1 m<sup>2</sup>/g, evidencing changes in the alumina surface. The conductivity, determined from measurements of impedance spectroscopy, at low frequency showed changes associated with the amount of the active phase. The values ranged from 2.61 &#215; 10<sup>&#8722;8</sup> &#177; 2.1 &#215; 10<sup>&#8722;9</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup> (pure alumina) to 7.33 &#215; 10<sup>&#8722;8</sup> &#177; 5.9 &#215; 10<sup>&#8722;9</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup>, 7.21 &#215; 10<sup>&#8722;8</sup> &#177; 5.8 &#215; 10<sup>&#8722;9</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup> and 4.51 &#215; 10<sup>&#8722;7</sup> &#177; 3.6 &#215; 10<sup>&#8722;8</sup> &#937;<sup>&#8722;1</sup>&#183;cm<sup>&#8722;1</sup> at room temperature for catalysts with nominal active phase contents of 5.0, 10.0 and 20.0%, respectively. Such results indicate that it is possible to modulate the electrical properties with variations in the synthesis parameters.https://www.mdpi.com/1420-3049/24/16/2984supported MnO<sub>X</sub>γ-aluminaionic conductivityporous materials
spellingShingle Nayda P. Arias
María E. Becerra
Oscar Giraldo
Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>
Molecules
supported MnO<sub>X</sub>
γ-alumina
ionic conductivity
porous materials
title Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>
title_full Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>
title_fullStr Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>
title_full_unstemmed Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>
title_short Electrical Behavior of a Catalyst Composed of Laminar Manganese Oxide Supported on γ-Al<sub>2</sub>O<sub>3</sub>
title_sort electrical behavior of a catalyst composed of laminar manganese oxide supported on γ al sub 2 sub o sub 3 sub
topic supported MnO<sub>X</sub>
γ-alumina
ionic conductivity
porous materials
url https://www.mdpi.com/1420-3049/24/16/2984
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AT mariaebecerra electricalbehaviorofacatalystcomposedoflaminarmanganeseoxidesupportedongalsub2subosub3sub
AT oscargiraldo electricalbehaviorofacatalystcomposedoflaminarmanganeseoxidesupportedongalsub2subosub3sub