The present research
provides a study of carbon-supported intermetallic
Pt-alloy electrocatalysts and assesses their stability against metal
dissolution in relation to the operating temperature and the potential
window using two advanced electrochemical methodologies: (i) the in-house
designed high-temperature disk electrode (HT-DE) methodology as well
as (ii) a modification of the electrochemical flow cell coupled to
an inductively coupled plasma mass spectrometer (EFC-ICP-MS) methodology,
allowing for highly sensitive time- and potential-resolved measurements
of metal dissolution. While the rate of carbon corrosion follows the
Arrhenius law and increases exponentially with temperature, the findings
of the present study contradict the generally accepted hypothesis
that the kinetics of Pt and subsequently the less noble metal dissolution
are supposed to be for the most part unaffected by temperature. On
the contrary, clear evidence is presented that in addition to the
importance of the voltage/potential window, the temperature is one
of the most critical parameters governing the stability of Pt and
thus, in the case of Pt-alloy electrocatalysts, also the ability of
the nanoparticles (NPs) to retain the less noble metal. Lastly, but
also very importantly, results indicate that the rate of Pt redeposition
significantly increases with temperature, which has been the main
reason why mechanistic interpretation of the temperature-dependent
kinetics related to the stability of Pt remained highly speculative
until now.
A fast and facile
pulse combustion (PC) method that allows for
the continuous production of multigram quantities of high-metal-loaded
and highly uniform supported metallic nanoparticles (SMNPs) is presented.
Namely, various metal on carbon (M/C) composites have been prepared
by using only three feedstock components: water, metal–salt,
and the supporting material. The present approach can be elegantly
utilized also for numerous other applications in electrocatalysis,
heterogeneous catalysis, and sensors. In this study, the PC-prepared
M/C composites were used as metal precursors for the Pt NPs deposition
using double passivation with the galvanic displacement method (DP
method). Lastly, by using thin-film rotating disc electrode (TF-RDE)
and gas-diffusion electrode (GDE) methodologies, we show that the
synergistic effects of combining PC technology with the DP method
enable production of superior intermetallic Pt–M electrocatalysts
with an improved oxygen reduction reaction (ORR) performance when
compared to a commercial Pt–Co electrocatalyst for proton exchange
membrane fuel cells (PEMFCs) application.
Carbon-supported Pt-based nanoalloys (CSPtNs) as the oxygen reduction reaction (ORR) electrocatalysts are considered state-of-the-art electrocatalysts for use in proton exchange membrane fuel cells (PEMFCs). Although their ORR activity performance is...
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