Co-Magneli phases electrocatalysts for hydrogen/oxygen evolution
Journal
International Journal of Hydrogen Energy
Date Issued
2010-10
Author(s)
Perica Paunovic, Orce Popovski, Emilija Fidancevska, Bogdan Ranguelov, Dafinka Stoevska Gogovska, Aleksandar T. Dimitrov, Svetomir Hadzi Jordanov
DOI
http://dx.doi.org/10.1016/j.ijhydene.2010.07.143
Abstract
The subject of this work is the use of non-stoichiometric titanium oxides e Magneli phases
as support material of Co-based electrocatalysts aimed for hydrogen/oxygen evolution
reaction. Commercial micro-scaled Ebonex (Altraverda, UK) was mechanically treated for
4, 8, 12, 16 and 20 h and further Co metallic phase was grafted by sol-gel method.
Morphology of Co/Ebonex electrocatalysts was observed by means of TEM and SEM
microscopy, while electrochemical behavior by means of cyclic voltammetry and steadystate
galvanostatic method.
As the duration of mechanical treatment increases, the size of Magneli phases decreases,
and consequently catalytic activity of the corresponding electrocatalysts increases.
Structural characteristics of the electrocatalysts deposited on Ebonex treated for 16 and
20 h are very similar. Also, these electrocatalysts show similar electrocatalytic activity for
both hydrogen and oxygen evolution reaction. So, optimal duration of mechanical treatment
of Magneli phases is in the range of 16e20 h.
Catalytic activity for hydrogen evolution of the studied electrocatalysts is inferior related to
the corresponding catalysts deposited on carbonaceous support materials such as activated
multiwalled carbon nanotubes or Vulcan XC-72 þ TiO2 (anatase). This inferiority is
due to lower real surface area of the Magneli phases.
Catalytic behavior for oxygen evolution achieves its maximal value even at the catalyst
deposited on Ebonex treated for 12 h and it is very promising related to the similar electrocatalytic
system such as CoPt/Ebonex.
as support material of Co-based electrocatalysts aimed for hydrogen/oxygen evolution
reaction. Commercial micro-scaled Ebonex (Altraverda, UK) was mechanically treated for
4, 8, 12, 16 and 20 h and further Co metallic phase was grafted by sol-gel method.
Morphology of Co/Ebonex electrocatalysts was observed by means of TEM and SEM
microscopy, while electrochemical behavior by means of cyclic voltammetry and steadystate
galvanostatic method.
As the duration of mechanical treatment increases, the size of Magneli phases decreases,
and consequently catalytic activity of the corresponding electrocatalysts increases.
Structural characteristics of the electrocatalysts deposited on Ebonex treated for 16 and
20 h are very similar. Also, these electrocatalysts show similar electrocatalytic activity for
both hydrogen and oxygen evolution reaction. So, optimal duration of mechanical treatment
of Magneli phases is in the range of 16e20 h.
Catalytic activity for hydrogen evolution of the studied electrocatalysts is inferior related to
the corresponding catalysts deposited on carbonaceous support materials such as activated
multiwalled carbon nanotubes or Vulcan XC-72 þ TiO2 (anatase). This inferiority is
due to lower real surface area of the Magneli phases.
Catalytic behavior for oxygen evolution achieves its maximal value even at the catalyst
deposited on Ebonex treated for 12 h and it is very promising related to the similar electrocatalytic
system such as CoPt/Ebonex.
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