II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-1
The performance of electrodes produced in this way was compared to that of traditional
electrodes, referred to as “pasted electrodes” here, because they are prepared by depositing a
mixture of platinum black (Au) powder and a Teflon suspension on a porous Teflon
membrane, followed by thermal annealing.
We tested the sensitivity, in the amperometric regime, to H 2 S and HCl of electrochemical
sensors employing either type of electrodes. We measured their sensitivity to selected gases,
their selectivity, background current, dynamic characteristics, long-term stability, and we
compared the results with those obtained using gas sensors produced by leading companies in
the field.
The MS deposited electrode resulted to be less sensitive than the pasted one, but it is
nonetheless promising in view of the much lower amount of noble metal involved, better
reproducibility, and better temperature stability. The results obtained are explained in terms of
structural differences between the two electrodes, as derived from their morphological
(Scanning Electron Microscopy, SEM), compositional (X-Ray Photoelectron Spectroscopy,
XPS) and structural (X-Ray Reflectivity, XRR) characterization.
Preliminary measurements were also performed to investigate possible compositional and
structural changes of electrodes that had worked a few weeks within the electrochemical gas
sensor.
Acknowledgments. This work was supported by NATO through the linkage Grant
PST.NR.CLG.981166.
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