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Multielectrode Teflon electrochemical nanocatalyst investigation system.

Hodnik N - MethodsX (2015)

Bottom Line: Typically this method is very time consuming and is subjected to impurity problems.In order to avoid these issues a new multielectrode electrochemical cell design is presented, where 8 different electrocatalysts can be measured simultaneously at identical conditions.The major advantages over TF-RDE method are: •Faster catalyst screening times.•Greater impurity tolerance.•The option of internal standard.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck-Institut für Eisenforschung GmbH, Max-Planck Str. 1, 40237 Düsseldorf, Germany ; National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.

ABSTRACT
The most common approach in the search for the optimal low temperature fuel cell catalyst remains "trial and error". Therefore, large numbers of different potential catalytic materials need to be screened. The well-established and most commonly used method for testing catalytic electrochemical activity under well-defined hydrodynamics is still thin film rotating disc electrode (TF-RDE). Typically this method is very time consuming and is subjected to impurity problems. In order to avoid these issues a new multielectrode electrochemical cell design is presented, where 8 different electrocatalysts can be measured simultaneously at identical conditions. The major advantages over TF-RDE method are: •Faster catalyst screening times.•Greater impurity tolerance.•The option of internal standard.

No MeSH data available.


(a) baseline and ORR polarization curves at two different rotations, (b) CO stripping experiment, (d) ORR polarization curves with subtracted background capacitive currents with different catalyst loadings and (c) Pt/C and PtCu/C (loading was 20 μg).
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fig0030: (a) baseline and ORR polarization curves at two different rotations, (b) CO stripping experiment, (d) ORR polarization curves with subtracted background capacitive currents with different catalyst loadings and (c) Pt/C and PtCu/C (loading was 20 μg).

Mentions: Electrochemical measurement: Here the example of Pt based low temperature fuel cell catalyst measurement protocol is given: first initiation or activation cycles are performed in order to obtain stable cyclic voltammogram. This is done in a saturated electrolyte with inert gas (Ar or N2) that was purged for at least 20 min (with magnetic stirrer turned on). Then the activity is measured in oxygen saturated solution (Fig. 6a). Lastly, electrochemical surface area is obtained with an integration of CO stripping curve (Fig. 6b). The procedure is similar as in the TF-RDE experiment [13]. In Fig. 6c we can see a typical multielectrode experiment where different loadings of Pt/C standard were measured at the same time. In Fig. 6d we can see onsets of two different electrocatalyst. It is clear that PtCu/C exhibits higher ORR activity then Pt/C (more about the nature of catalyst and their activates can be found in Ref. [4]). Compared to TF-RDE experiment performed with PtCu/C one can observe the same onset potential, which indicates the same catalyst activity. However, there is a clear difference in the diffusion region due to different hydrodynamics (Fig. 7). If interested in methanol oxidation activity CO stripping is measured before adding methanol. Optionally one could also perform other electrochemical measurements such as different reactions (hydrogen, oxidation, ethanol oxidation, nitrous oxide reduction, oxygen evolution, etc.), degradation protocols (cycling or potential hold) [12], treatment of either identical location TEM grids or SEM graphite holders [13].


Multielectrode Teflon electrochemical nanocatalyst investigation system.

Hodnik N - MethodsX (2015)

(a) baseline and ORR polarization curves at two different rotations, (b) CO stripping experiment, (d) ORR polarization curves with subtracted background capacitive currents with different catalyst loadings and (c) Pt/C and PtCu/C (loading was 20 μg).
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487726&req=5

fig0030: (a) baseline and ORR polarization curves at two different rotations, (b) CO stripping experiment, (d) ORR polarization curves with subtracted background capacitive currents with different catalyst loadings and (c) Pt/C and PtCu/C (loading was 20 μg).
Mentions: Electrochemical measurement: Here the example of Pt based low temperature fuel cell catalyst measurement protocol is given: first initiation or activation cycles are performed in order to obtain stable cyclic voltammogram. This is done in a saturated electrolyte with inert gas (Ar or N2) that was purged for at least 20 min (with magnetic stirrer turned on). Then the activity is measured in oxygen saturated solution (Fig. 6a). Lastly, electrochemical surface area is obtained with an integration of CO stripping curve (Fig. 6b). The procedure is similar as in the TF-RDE experiment [13]. In Fig. 6c we can see a typical multielectrode experiment where different loadings of Pt/C standard were measured at the same time. In Fig. 6d we can see onsets of two different electrocatalyst. It is clear that PtCu/C exhibits higher ORR activity then Pt/C (more about the nature of catalyst and their activates can be found in Ref. [4]). Compared to TF-RDE experiment performed with PtCu/C one can observe the same onset potential, which indicates the same catalyst activity. However, there is a clear difference in the diffusion region due to different hydrodynamics (Fig. 7). If interested in methanol oxidation activity CO stripping is measured before adding methanol. Optionally one could also perform other electrochemical measurements such as different reactions (hydrogen, oxidation, ethanol oxidation, nitrous oxide reduction, oxygen evolution, etc.), degradation protocols (cycling or potential hold) [12], treatment of either identical location TEM grids or SEM graphite holders [13].

Bottom Line: Typically this method is very time consuming and is subjected to impurity problems.In order to avoid these issues a new multielectrode electrochemical cell design is presented, where 8 different electrocatalysts can be measured simultaneously at identical conditions.The major advantages over TF-RDE method are: •Faster catalyst screening times.•Greater impurity tolerance.•The option of internal standard.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck-Institut für Eisenforschung GmbH, Max-Planck Str. 1, 40237 Düsseldorf, Germany ; National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.

ABSTRACT
The most common approach in the search for the optimal low temperature fuel cell catalyst remains "trial and error". Therefore, large numbers of different potential catalytic materials need to be screened. The well-established and most commonly used method for testing catalytic electrochemical activity under well-defined hydrodynamics is still thin film rotating disc electrode (TF-RDE). Typically this method is very time consuming and is subjected to impurity problems. In order to avoid these issues a new multielectrode electrochemical cell design is presented, where 8 different electrocatalysts can be measured simultaneously at identical conditions. The major advantages over TF-RDE method are: •Faster catalyst screening times.•Greater impurity tolerance.•The option of internal standard.

No MeSH data available.