Atomic Scale Insights into Electrochemical Dissolution of Janus Pt–SnO₂ Nanoparticles in the Presence of Ethanol in Acidic Media: An IL-STEM and EFC–ICP–MS Study

Abstract

The studies on Pt-or Pt alloy-based catalysts for ethanol oxidation have been focused mostly on their activity, with much less emphasis on their stability. Dissolution of commercial Pt−SnO 2 /C electrocatalyst for direct ethanol fuel cells was investigated on the atomic scale by employing two advanced electrochemical characterization techniques: (i) identical location scanning transmission electron microscopy (IL-STEM) and (ii) electrochemical flow cell connected to inductively coupled mass spectrometry (EFC−ICP−MS). IL-STEM provides electrochemically induced atomic scale insights into morphological and structural changes of Pt−SnO 2 /C Janus type nanoparticles, and the second methodological configuration enables potential-and timeresolved dissolution monitoring of individual metal counterparts with extremely high sensitivity, even in the presence of ethanol. We observe that Sn is mostly dissolving in the anodic potential ramp, which is, as a rule, not affected by the presence of ethanol. Surprisingly, Pt dissolution gets dramatically enhanced in the presence of ethanol with the onset already at 0.57 V. Compared to the experiment without ethanol, the onset is at 1.1 V, which is typical for Pt. We discuss the possible mechanisms governing these alterations.

Resolving the nanoparticles' structure-property relationships at the atomic level: a study of Pt-based electrocatalysts

“…Since the inceptions of the methodology by K. J.J. Mayrhofer et al. ( Meier et al, 2012a , 2012b , 2014 ; Schlögl et al., 2011 ), the game of “Spot the difference” ( Scheme 2 ) ( Hodnik and Cherevko, 2019 ) has been recently re-defined to retrieve information at the atomic scale ( Jovanovič et al., 2018b ; Rasouli et al., 2019 ; Ruiz-Zepeda et al., 2019 ), adapting it to something more close to a semi in-situ method. Crucially, atomic-resolution electron microscopy images provide much more information than just those recorded with a nanometer-scale resolution.…”

Electrochemical On‐line ICP‐MS in Electrocatalysis Research

“…Since no data on dissolution of non‐alloyed Pt/C was presented, it is not clear if this can be attributed to an improved sensitivity of the used setup alone or to any possible un‐stabilizing effect of Co (note that according to theoretical works presence of Co can be beneficial in stabilizing Pt). Platinum dissolution at lower potentials is known but typically attributed to the presence of complexing or destabilizing elements in the electrolyte . Another important observation is that at low potentials (E <0.9 V RHE ) anodic dissolution is the dominating mechanisms.…”

Nanoparticles and Single Atoms in Commercial Carbon-Supported Platinum-Group Metal Catalysts

“…In addition to the commercial materials discussed in this work, our experience with STEM analysis of carbon-supported catalysts suggested that atomic species are indeed a common companion to metal nanoparticles. For example, we detected single atoms in a commercial PtRu/C catalyst [38] and commercial Pt-SnO 2 /C catalyst [39] on a high-surface area nitrogen-doped carbon alongside Pt nanoparticles [32] and on a graphite rod after electrochemical deposition of Ag [40].…”