In Situ Stability Studies of Platinum Nanoparticles Supported on Ruthenium−Titanium Mixed Oxide (RTO) for Fuel Cell Cathodes

• DOI: 10.1021/acscatal.8b02498
• Publication Date: 2018-09-10T14:30:06Z
• Authors: Elisabeth Hornberger; Arno Bergmann; Henrike Schmies; Stefanie Kühl; Guanxiong Wang; Jakub Drnec; Daniel J. S. Sand...; Vijay Ramani; Serhiy Cherevko; Karl J. J. Mayrhofer; Peter Strasser
• Keywords: Titanium oxide; Platinum nanoparticles; Ruthenium oxide

Using a variety of in situ techniques, we tracked the structural stability and concomitantly electrocatalytic oxygen reduction reaction (ORR) platinum nanoparticles on ruthenium–titanium mixed oxide (RTO) supports during electrochemical accelerated stress tests, mimicking fuel cell operating conditions. High-energy X-ray diffraction (HE-XRD) offered insights evolution morphology structure RTO-supported Pt potential cycling. The changes atomic composition were using scanning flow measurements coupled to inductively plasma mass spectrometry (SFC-ICP-MS). We excluded agglomeration, particle growth, dissolution, or detachment as cause for observed losses catalytic ORR activity. Instead, argue that surface poisoning is most likely rate decrease. Data suggest gradual growth thin layer due strong metal–support interaction (SMSI) plausible reason suppressed discuss implications identified catalyst degradation pathway, which appear be specific supports. Our conclusions offer previously unaddressed aspects related oxide-supported metal electrocatalysts frequently deployed cells, electrolyzers, metal–air batteries.