Suppressing platinum electrocatalyst degradation via a high-surface-area organic matrix support

Smiljanić, Milutin (author), Bele, Marjan (author), Moriau, Leonard (author), Vélez Santa, John Fredy (author), Menart, Svit (author), Šala, Martin (author), Hrnjić, Armin (author), Jovanovič, Primož (author), Ruiz-Zepeda, Francisco (author), Gaberšček, Miran (author), Hodnik, Nejc (author)

Degradation of carbon-supported Pt nanocatalysts in fuel cells and electrolyzers hinders widespread commercialization of these green technologies. Transition between oxidized and reduced states of Pt during fast potential spikes triggers significant Pt dissolution. Therefore, designing Pt-based catalysts able to withstand such conditions is of critical importance. We report here on a strategy to suppress Pt dissolution by using an organic matrix tris(aza)pentacene (TAP) as an alternative support material for Pt. The major benefit of TAP is its potential-dependent conductivity in aqueous media, which was directly evidenced by electrochemical impedance spectroscopy. At potentials below ∼0.45 V$_{RHE}$, TAP is protonated and its conductivity is improved, which enables supported Pt to run hydrogen reactions. At potentials corresponding to Pt oxidation/reduction (>∼0.45 V$_{RHE}$), TAP is deprotonated and its conductivity is restricted. Tunable conductivity of TAP enhanced the durability of the Pt/TAP with respect to Pt/C when these two materials were subjected to the same degradation protocol (0.1 M HClO$_4$ electrolyte, 3000 voltammetric scans, 1 V/s, 0.05−1.4 V$_{RHE}$). The exceptional stability of Pt/TAP composite on a nanoscale level was confirmed by identical location TEM imaging before and after the used degradation protocol. Suppression of transient Pt dissolution from Pt/TAP with respect to the Pt/C benchmark was directly measured in a setup consisting of an electrochemical flow cell connected to inductively coupled plasma-mass spectrometry.

• Language: English
• Keywords: degradation, platinum, electrodes, catalysts, dissolution
• 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: 2022
• Number of pages: Str. 3540-3548
• Numbering: Vol. 7, iss. 4
• PID: 20.500.12556/RUL-140636
• UDC: 544.5/.6
• ISSN on article: 2470-1343
• DOI: 10.1021/acsomega.1c06028
• COBISS.SI-ID: 95435011
• Publication date in RUL: 16.09.2022

Record is a part of a journal

• Title: ACS omega
• Shortened title: ACS omega
• Publisher: American Chemical Society
• ISSN: 2470-1343
• COBISS.SI-ID: 525873945

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, elektrokataliza, gorivne celice, ogljik, Pt, reakcije