New nano-structured and interactive supported composite electrocatalysts for hydrogen evolution with partially replaced platinum loading
Journal
International Journal of Hydrogen Energy
Date Issued
2009-04
Author(s)
Perica Paunovic, Ivan Radev, Aleksandar T. Dimitrov, Orce Popovski, Elefteria Lefterova, Evelina Slavcheva, Svetomir Hadzi Jordanov
DOI
10.1016/j.ijhydene.2009.01.024
Abstract
This work is concerned with preparation and characterization of nano-structured
composite electrocatalytic material for hydrogen evolution based on CoPt hyper d-metallic
phase and anatase (TiO2) hypo d-phase, both deposited on multiwalled carbon nanotubes
(MWCNTs) as a carbon substrate. The main goal is partially or completely to replace Pt as
the electrocatalytic material. Four electrocatalytic systems were prepared with common
composition 10% Me þ 18% TiO2 þ MWCNTs, where Me ¼ Co, CoPt (4:1, wt. ratio), CoPt (1:1,
wt. ratio) and Pt. The structural changes and their influence on electrocatalytic activity
were studied by means of XRD, TEM, SEM and FTIR. The electrocatalytic activity was
assessed in aqueous alkaline and polymer acidic electrolytes by means of steady-state
galvanostatic method. It was found that Co strongly affects the platinum particle size. The
addition of Co reduces platinum particle’s size from 11 nm (in pure Pt metallic system) to
4 nm (in both systems 4:1 and 1:1), i.e. almost by 3 times. The corresponding increase of the
surface area and the number of the active catalytic centres improves the efficiency, despite
the fact that the amount of used platinum was decreased up to 5 times. The catalyst based
on CoPt (1:1) performed the best, while the activity of the pure platinum and CoPt (4:1)
systems were very close. Generally, the studied electrocatalysts have shown good and
stable performances for hydrogen evolution in PEM electrochemical cell. The influence of
the hydrogen electrodes under investigation on the water electrolysis efficiency at current
density of 0.3 A cm 2 was assessed, using previous data oxygen evolution on IrOx electrode.
Related to the performances of commercial Pt (ELAT) electrode, when hydrogen electrodes
with the prepared mixed electrocatalysts were used, the water electrolysis efficiency was
only 5% lower for CoPt (1:1), nearly 10% lower for CoPt (4:1) and 13% lower in the case of
pure Co-based electrocatalyst.
composite electrocatalytic material for hydrogen evolution based on CoPt hyper d-metallic
phase and anatase (TiO2) hypo d-phase, both deposited on multiwalled carbon nanotubes
(MWCNTs) as a carbon substrate. The main goal is partially or completely to replace Pt as
the electrocatalytic material. Four electrocatalytic systems were prepared with common
composition 10% Me þ 18% TiO2 þ MWCNTs, where Me ¼ Co, CoPt (4:1, wt. ratio), CoPt (1:1,
wt. ratio) and Pt. The structural changes and their influence on electrocatalytic activity
were studied by means of XRD, TEM, SEM and FTIR. The electrocatalytic activity was
assessed in aqueous alkaline and polymer acidic electrolytes by means of steady-state
galvanostatic method. It was found that Co strongly affects the platinum particle size. The
addition of Co reduces platinum particle’s size from 11 nm (in pure Pt metallic system) to
4 nm (in both systems 4:1 and 1:1), i.e. almost by 3 times. The corresponding increase of the
surface area and the number of the active catalytic centres improves the efficiency, despite
the fact that the amount of used platinum was decreased up to 5 times. The catalyst based
on CoPt (1:1) performed the best, while the activity of the pure platinum and CoPt (4:1)
systems were very close. Generally, the studied electrocatalysts have shown good and
stable performances for hydrogen evolution in PEM electrochemical cell. The influence of
the hydrogen electrodes under investigation on the water electrolysis efficiency at current
density of 0.3 A cm 2 was assessed, using previous data oxygen evolution on IrOx electrode.
Related to the performances of commercial Pt (ELAT) electrode, when hydrogen electrodes
with the prepared mixed electrocatalysts were used, the water electrolysis efficiency was
only 5% lower for CoPt (1:1), nearly 10% lower for CoPt (4:1) and 13% lower in the case of
pure Co-based electrocatalyst.
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