The present study showcases the importance of temperature and potential window for evaluation of Pt-based supported electrocatalyst stability. A platinum based commercial material with an average size of Pt nanoparticles between 2-3 nm (Pt/C) and its thermally annealed analogue with an average particle size of ∼5 nm (Pt/C-HT) are considered. X-ray diffraction (XRD), ex situ transmission electron microscopy (TEM) imaging and thin film rotating disc electrode (TF-RDE) along with proprietary hightemperature disc electrode (HT-DE) are used for electrocatalysts inspection. The study shows a clear dependence between the electrochemical surface area (ECSA) loss and the temperature increase during the potentiodynamic accelerated degradation test (ADT). Additionally it is demonstrated that selection of the lower and upper potential limits in ADT protocol plays an important role in ECSA loss. Comparing various results obtained on Pt/C and Pt/C-HT, we show that varying ADT conditions of temperature and different potential windows is crucial for adequate evaluation and stability interpretation of potentially promising novel electrocatalysts and that relatively mild ADT conditions (i.e. 0.4-1.0 V RHE , RT) can be potentially misleading.

Preparation of large quantities of high-performance supported Pt-alloy electrocatalysts is crucial for the faster development and implementation of low-temperature proton exchange membrane fuel cells (PEMFCs). One of the prospective nanofabrication synthesis methods is based on the galvanic displacement (GD) reaction. Af acile,h ighly reproducible,g ram scale,w ater-based double passivation GD method is now presented for the synthesis of carbon-supported Pt-M nanoparticles (M = Cu, Ni, Co). It offers great flexibility over the catalyst design, such as the choice of the sacrificial metal (M), variation of the chemical composition of alloy, variation of total metal loading (Pt + M) on carbon support, or even variation of the carbon support itself.T he obtained Ptalloyc atalysts are several times more active compared to aP t reference and exhibits better stability during accelerated degradation tests performed at 60 8 8C.

Preparation of large quantities of high-performance supported Pt-alloy electrocatalysts is crucial for the faster development and implementation of low-temperature proton exchange membrane fuel cells (PEMFCs). One of the prospective nanofabrication synthesis methods is based on the galvanic displacement (GD) reaction. Af acile,h ighly reproducible,g ram scale,w ater-based double passivation GD method is now presented for the synthesis of carbon-supported Pt-M nanoparticles (M = Cu, Ni, Co). It offers great flexibility over the catalyst design, such as the choice of the sacrificial metal (M), variation of the chemical composition of alloy, variation of total metal loading (Pt + M) on carbon support, or even variation of the carbon support itself.T he obtained Ptalloyc atalysts are several times more active compared to aP t reference and exhibits better stability during accelerated degradation tests performed at 60 8 8C.

Carbon-supported Pt-based nanoalloys (CSPtNs) as the oxygen reduction reaction (ORR) electrocatalysts are considered state-of-the-art electrocatalysts for use in proton exchange membrane fuel cells (PEMFCs). Although their ORR activity performance is...