Electrochemical Stability of Rhodium–Platinum Core–Shell Nanoparticles: An Identical Location Scanning Transmission Electron Microscopy Study

Abstract

Rhodium–platinum core–shell nanoparticles on a carbon support (Rh@Pt/C NPs) are promising candidates as anode catalysts for polymer electrolyte membrane fuel cells. However, their electrochemical stability needs to be further explored for successful application in commercial fuel cells. Here we employ identical location scanning transmission electron microscopy to track the morphological and compositional changes of Rh@Pt/C NPs during potential cycling (10 000 cycles, 0.06–0.8 VRHE, 0.5 H2SO4) down to the atomic level, which are then used for understanding the current evolution occurring during the potential cycles. Our results reveal a high stability of the Rh@Pt/C system and point toward particle detachment from the carbon support as the main degradation mechanism.

Deciphering the role of Fe impurities in the electrolyte boosting the OER activity of LaNiO3

“…In identical location IL-STEM, the same region of the sample can be studied before and aer an electrocatalytic reaction, and has been used for determining degradation mechanisms 33,34 and the nature of active species 35 of nanocatalysts. For the IL experiments, a 10 mL drop of a 0.3 mg mL −1 dispersion of LaNiO 3 on deionized water was drop-cast on a hole carboncoated Au TEM nder grid (Plano).…”

Expanding the Potential of Identical Location Scanning Transmission Electron Microscopy for Gas Evolving Reactions: Stability of Rhenium Molybdenum Disulfide Nanocatalysts for Hydrogen Evolution Reaction

“…1,2 In IL(S)-TEM, the same region of a TEM specimen is analyzed before and after electrochemical testing. This methodology allows for direct correlation of the morphological and compositional changes of nanocatalysts to the electrochemical conditions they were subjected to, thus providing insights to the corrosion mechanisms 3,4 or the nature of the active species 5 down to the atomic scale. When compared to in situ liquid cell (S)TEM, 6 IL(S)TEM possesses the advantages of higher spatial resolution, longer term studies of up to several thousands of potential cycles, and reduced electron beam-induced effects, which can produce undesirable side reactions 7,8 First introduced by Mayrhofer et al, 9,10 IL(S)TEM was originally developed for the study of the degradation of fuel cell nanocatalysts, with several studies focusing on the effects of oxygen reduction reaction 11,12 and ramping up/down conditions 3,13 on the nanocatalysts.…”

“…Identical location (scanning) transmission electron microscopy (IL­(S)­TEM) is a powerful technique to study the stability of nanocatalysts during electrochemical reactions. , In IL­(S)­TEM, the same region of a TEM specimen is analyzed before and after electrochemical testing. This methodology allows for direct correlation of the morphological and compositional changes of nanocatalysts to the electrochemical conditions they were subjected to, thus providing insights to the corrosion mechanisms , or the nature of the active species down to the atomic scale. When compared to in situ liquid cell (S)­TEM, IL­(S)­TEM possesses the advantages of higher spatial resolution, longer term studies of up to several thousands of potential cycles, and reduced electron beam-induced effects, which can produce undesirable side reactions , …”