Enhancement of the catalytic activity of fe phthalocyanine for the reduction of O 2 anchored to Au(111) via conjugated self-assembled monolayers of aromatic thiols as compared to Cu phthalocyanine

Ingrid Ponce, J. Francisco Silva, Ruben Oñate, Marcos Caroli Rezende, Maritza A. Paez, José H. Zagal, Jorge Pavez, Fernando Mendizabal, Sebastián Miranda-Rojas, Alvaro Muñoz-Castro, Ramiro Arratia-Pérez

Resultado de la investigación: Article

40 Citas (Scopus)

Resumen

We have prepared self-assembled monolayers (SAMs) of 4-aminothiophenol (4-ATP) and 1-(4-mercaptophenyl)-2,6-diphenyl-4-(4-pyridyl)pyridinium tetrafluoroborate (MDPP) functionalized with iron phthalocyanine (FePc) and copper phthalocyanine (CuPc) adsorbed on gold (111) electrodes. The catalytic activity of these SAMs/MPc was examined for the reduction of O 2 in aqueous solutions and compared to that of bare gold and with gold coated directly with preadsorbed MPc molecules. Scanning tunneling microscopy (STM) studies confirm the functionalization of the 4-ATP by MPc. STM images reveal that iron phthalocyanine molecules are chemically anchored to 4-aminothiophenol organic monolayers, probably having an "umbrella" type orientation with regards to the surface. The electrocatalytic studies carried out with Au/4-ATP/FePc and Au/MDPP/FePc electrodes show that the O 2 reduction takes place by the transfer of 4-electron to give water in contrast to a 2-electron transfer process observed for the bare gold. The modified electrode obtained by simple adsorption of FePc directly to the Au(111) surface still promotes the 4-electron reduction process, but it shows a lower activity than the electrodes involving SAMs with FePc molecules positioned at the outmost portion of the self-assembled monolayers. The activity of the electrodes increases as follow: Au < Au/FePc < Au/4-ATP/FePc < Au/MDPP/FePc with the highest activity when FePc molecules are more separated from the Au surface. In contrast, the less active CuPc shows almost the same activity in all three configurations. Theoretical calculations suggest the importance of the back-bonding into the adduct formation, showing the relevance of the supporting gold surface on the electron-transfer process mediated by anchoring ligands.

Idioma originalEnglish
Páginas (desde-hasta)15329-15341
Número de páginas13
PublicaciónJournal of Physical Chemistry C
Volumen116
N.º29
DOI
EstadoPublished - 26 jul 2012

Huella dactilar

Self assembled monolayers
Sulfhydryl Compounds
thiols
Gold
catalytic activity
Catalyst activity
gold
Electrodes
electrodes
augmentation
Molecules
Electrons
Scanning tunneling microscopy
scanning tunneling microscopy
molecules
electron transfer
Iron
iron
adducts
Monolayers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry

Citar esto

Ponce, Ingrid ; Silva, J. Francisco ; Oñate, Ruben ; Rezende, Marcos Caroli ; Paez, Maritza A. ; Zagal, José H. ; Pavez, Jorge ; Mendizabal, Fernando ; Miranda-Rojas, Sebastián ; Muñoz-Castro, Alvaro ; Arratia-Pérez, Ramiro. / Enhancement of the catalytic activity of fe phthalocyanine for the reduction of O 2 anchored to Au(111) via conjugated self-assembled monolayers of aromatic thiols as compared to Cu phthalocyanine. En: Journal of Physical Chemistry C. 2012 ; Vol. 116, N.º 29. pp. 15329-15341.
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abstract = "We have prepared self-assembled monolayers (SAMs) of 4-aminothiophenol (4-ATP) and 1-(4-mercaptophenyl)-2,6-diphenyl-4-(4-pyridyl)pyridinium tetrafluoroborate (MDPP) functionalized with iron phthalocyanine (FePc) and copper phthalocyanine (CuPc) adsorbed on gold (111) electrodes. The catalytic activity of these SAMs/MPc was examined for the reduction of O 2 in aqueous solutions and compared to that of bare gold and with gold coated directly with preadsorbed MPc molecules. Scanning tunneling microscopy (STM) studies confirm the functionalization of the 4-ATP by MPc. STM images reveal that iron phthalocyanine molecules are chemically anchored to 4-aminothiophenol organic monolayers, probably having an {"}umbrella{"} type orientation with regards to the surface. The electrocatalytic studies carried out with Au/4-ATP/FePc and Au/MDPP/FePc electrodes show that the O 2 reduction takes place by the transfer of 4-electron to give water in contrast to a 2-electron transfer process observed for the bare gold. The modified electrode obtained by simple adsorption of FePc directly to the Au(111) surface still promotes the 4-electron reduction process, but it shows a lower activity than the electrodes involving SAMs with FePc molecules positioned at the outmost portion of the self-assembled monolayers. The activity of the electrodes increases as follow: Au < Au/FePc < Au/4-ATP/FePc < Au/MDPP/FePc with the highest activity when FePc molecules are more separated from the Au surface. In contrast, the less active CuPc shows almost the same activity in all three configurations. Theoretical calculations suggest the importance of the back-bonding into the adduct formation, showing the relevance of the supporting gold surface on the electron-transfer process mediated by anchoring ligands.",
author = "Ingrid Ponce and Silva, {J. Francisco} and Ruben O{\~n}ate and Rezende, {Marcos Caroli} and Paez, {Maritza A.} and Zagal, {Jos{\'e} H.} and Jorge Pavez and Fernando Mendizabal and Sebasti{\'a}n Miranda-Rojas and Alvaro Mu{\~n}oz-Castro and Ramiro Arratia-P{\'e}rez",
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Enhancement of the catalytic activity of fe phthalocyanine for the reduction of O 2 anchored to Au(111) via conjugated self-assembled monolayers of aromatic thiols as compared to Cu phthalocyanine. / Ponce, Ingrid; Silva, J. Francisco; Oñate, Ruben; Rezende, Marcos Caroli; Paez, Maritza A.; Zagal, José H.; Pavez, Jorge; Mendizabal, Fernando; Miranda-Rojas, Sebastián; Muñoz-Castro, Alvaro; Arratia-Pérez, Ramiro.

En: Journal of Physical Chemistry C, Vol. 116, N.º 29, 26.07.2012, p. 15329-15341.

Resultado de la investigación: Article

TY - JOUR

T1 - Enhancement of the catalytic activity of fe phthalocyanine for the reduction of O 2 anchored to Au(111) via conjugated self-assembled monolayers of aromatic thiols as compared to Cu phthalocyanine

AU - Ponce, Ingrid

AU - Silva, J. Francisco

AU - Oñate, Ruben

AU - Rezende, Marcos Caroli

AU - Paez, Maritza A.

AU - Zagal, José H.

AU - Pavez, Jorge

AU - Mendizabal, Fernando

AU - Miranda-Rojas, Sebastián

AU - Muñoz-Castro, Alvaro

AU - Arratia-Pérez, Ramiro

PY - 2012/7/26

Y1 - 2012/7/26

N2 - We have prepared self-assembled monolayers (SAMs) of 4-aminothiophenol (4-ATP) and 1-(4-mercaptophenyl)-2,6-diphenyl-4-(4-pyridyl)pyridinium tetrafluoroborate (MDPP) functionalized with iron phthalocyanine (FePc) and copper phthalocyanine (CuPc) adsorbed on gold (111) electrodes. The catalytic activity of these SAMs/MPc was examined for the reduction of O 2 in aqueous solutions and compared to that of bare gold and with gold coated directly with preadsorbed MPc molecules. Scanning tunneling microscopy (STM) studies confirm the functionalization of the 4-ATP by MPc. STM images reveal that iron phthalocyanine molecules are chemically anchored to 4-aminothiophenol organic monolayers, probably having an "umbrella" type orientation with regards to the surface. The electrocatalytic studies carried out with Au/4-ATP/FePc and Au/MDPP/FePc electrodes show that the O 2 reduction takes place by the transfer of 4-electron to give water in contrast to a 2-electron transfer process observed for the bare gold. The modified electrode obtained by simple adsorption of FePc directly to the Au(111) surface still promotes the 4-electron reduction process, but it shows a lower activity than the electrodes involving SAMs with FePc molecules positioned at the outmost portion of the self-assembled monolayers. The activity of the electrodes increases as follow: Au < Au/FePc < Au/4-ATP/FePc < Au/MDPP/FePc with the highest activity when FePc molecules are more separated from the Au surface. In contrast, the less active CuPc shows almost the same activity in all three configurations. Theoretical calculations suggest the importance of the back-bonding into the adduct formation, showing the relevance of the supporting gold surface on the electron-transfer process mediated by anchoring ligands.

AB - We have prepared self-assembled monolayers (SAMs) of 4-aminothiophenol (4-ATP) and 1-(4-mercaptophenyl)-2,6-diphenyl-4-(4-pyridyl)pyridinium tetrafluoroborate (MDPP) functionalized with iron phthalocyanine (FePc) and copper phthalocyanine (CuPc) adsorbed on gold (111) electrodes. The catalytic activity of these SAMs/MPc was examined for the reduction of O 2 in aqueous solutions and compared to that of bare gold and with gold coated directly with preadsorbed MPc molecules. Scanning tunneling microscopy (STM) studies confirm the functionalization of the 4-ATP by MPc. STM images reveal that iron phthalocyanine molecules are chemically anchored to 4-aminothiophenol organic monolayers, probably having an "umbrella" type orientation with regards to the surface. The electrocatalytic studies carried out with Au/4-ATP/FePc and Au/MDPP/FePc electrodes show that the O 2 reduction takes place by the transfer of 4-electron to give water in contrast to a 2-electron transfer process observed for the bare gold. The modified electrode obtained by simple adsorption of FePc directly to the Au(111) surface still promotes the 4-electron reduction process, but it shows a lower activity than the electrodes involving SAMs with FePc molecules positioned at the outmost portion of the self-assembled monolayers. The activity of the electrodes increases as follow: Au < Au/FePc < Au/4-ATP/FePc < Au/MDPP/FePc with the highest activity when FePc molecules are more separated from the Au surface. In contrast, the less active CuPc shows almost the same activity in all three configurations. Theoretical calculations suggest the importance of the back-bonding into the adduct formation, showing the relevance of the supporting gold surface on the electron-transfer process mediated by anchoring ligands.

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U2 - 10.1021/jp301093q

DO - 10.1021/jp301093q

M3 - Article

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EP - 15341

JO - Journal of Physical Chemistry C

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