Adjusting the operational potential window as a tool for prolonging the durability of carbon-supported Pt-alloy nanoparticles as oxygen reduction reaction electrocatalysts

Đukić, Tina (author), Moriau, Leonard (author), Klofutar, Iva (author), Šala, Martin (author), Pavko, Luka (author), González López, Francisco Javier (author), Ruiz-Zepeda, Francisco (author), Pavlišič, Andraž (author), Hotko, Miha (author), Gatalo, Matija (author), Hodnik, Nejc (author)

A current trend in the investigation of state-of-the-art Pt-alloys as proton exchange membrane fuel cell (PEMFC) electrocatalysts is to study their long-term stability as a bottleneck for their full commercialization. Although many parameters have been appropriately addressed, there are still certain issues that must be considered. Here, the stability of an experimental Pt-Co/C electrocatalyst is investigated by high-temperature accelerated degradation tests (HT-ADTs) in a high-temperature disk electrode (HT-DE) setup, allowing the imitation of close-to-real operational conditions in terms of temperature (60 °C). Although the US Department of Energy (DoE) protocol has been chosen as the basis of the study (30,000 trapezoidal wave cycling steps between 0.6 and 0.95 V$_{RHE}$ with a 3 s hold time at both the lower potential limit (LPL) and the upper potential limit (UPL)), this works demonstrates that limiting both the LPL and UPL (from 0.6−0.95 to 0.7−0.85 V$_{RHE}$) can dramatically reduce the degradation rate of state-of-the-art Pt-alloy electrocatalysts. This has been additionally confirmed with the use of an electrochemical flow cell coupled to inductively coupled plasma mass spectrometry (EFC-ICP-MS), which enables real-time monitoring of the dissolution mechanisms of Pt and Co. In line with the HT-DE methodology observations, a dramatic decrease in the total dissolution of Pt and Co has once again been observed upon narrowing the potential window to 0.7−0.85 V$_{RHE}$ rather than 0.6−0.95 V$_{RHE}$. Additionally, the effect of the potential hold time at both LPL and UPL on metal dissolution has also been investigated. The findings demonstrate that the dissolution rate of both metals is proportional to the hold time at UPL regardless of the applied potential window, whereas the hold time at the LPL does not appear to be as detrimental to the stability of metals.

• Language: English
• Keywords: fuel cells, oxygen reduction reaction, platinum alloys, durability, accelerated degradation tests, potential window, hold time, dissolution, electrocatalysts, electrodes, metals, platinum
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: Str. 4303–4317
• Numbering: Vol. 14, iss. 6
• PID: 20.500.12556/RUL-156061
• UDC: 544.5/.6
• ISSN on article: 2155-5435
• DOI: 10.1021/acscatal.3c06251
• COBISS.SI-ID: 190114819
• Publication date in RUL: 06.05.2024

Record is a part of a journal

• Title: ACS catalysis
• Shortened title: ACS catal.
• Publisher: American Chemical Society
• ISSN: 2155-5435
• COBISS.SI-ID: 518529817

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: elektrokemija, gorivne celice, zlitine, platina, reakcija redukcije kisika