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...

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A versatile approach to the production of cluster- and single atom-based thin-film electrode composites is presented. The developed TiO x N y –Ir catalyst was prepared from sputtered Ti–Ir alloy constituted of 0.8 ± 0.2 at % Ir in α-Ti solid solution. The Ti–Ir solid solution on the Ti metal foil substrate was anodically oxidized to form amorphous TiO2–Ir and later subjected to heat treatment in air and in ammonia to prepare the final catalyst. Detailed morphological, structural, compositional, and electrochemical characterization revealed a nanoporous film with Ir single atoms and clusters that are present throughout the entire film thickness and concentrated at the Ti/TiO x N y –Ir interface as a result of the anodic oxidation mechanism. The developed TiO x N y –Ir catalyst exhibits very high oxygen evolution reaction activity in 0.1 M HClO4, reaching 1460 A g–1 Ir at 1.6 V vs reference hydrogen electrode. The new preparation concept of single atom- and cluster-based thin-film catalysts has wide potential applications in electrocatalysis and beyond. In the present paper, a detailed description of the new and unique method and a high-performance thin film catalyst are provided along with directions for the future development of high-performance cluster and single-atom catalysts prepared from solid solutions.

Molybdenum disulfide (MoS2) is widely regarded as a competitive hydrogen evolution reaction (HER) catalyst to replace platinum in proton exchange membrane water electrolysers (PEMWEs). Despite the extensive knowledge of its HER activity, stability insights under HER operation are scarce. This is paramount to ensure long-term operation of Pt-free PEMWEs, and gain full understanding on the electrocatalytically-induced processes responsible for HER active site generation. The latter are highly dependent on the MoS2 allotropic phase, and still under debate. We rigorously assess these by simultaneously monitoring Mo and S dissolution products using a dedicated scanning flow cell coupled with downstream analytics (ICP-MS), besides an electrochemical mass spectrometry setup for volatile species analysis. We observe that MoS2 stability is phase-dependent: lamellar-like MoS2 is highly unstable under open circuit conditions, whereas cluster-like amorphous MoS3 − x instability is induced by S loss and undercoordinated Mo site generation. Guidelines to operate non-noble PEMWEs are therefore provided based on the stability number metrics, and an HER mechanism which accounts for Mo and S dissolution pathways is proposed.

Herein, a comparative analysis of two case example catalysts for electrocatalytic hydrogenation (ECH) of furfural under acidic conditions, namely a copper polycrystalline disc and copper nanoparticles dispersed on carbon support, is performed. To gain a detailed insight on ECH trends, a task‐specific methodology is employed based on electrochemistry–mass spectrometry coupling, which enabled time‐ and potential‐resolved detection of volatile ECH products, i.e., 2‐methylfurane (2‐MF) and H2. In this way, the ability to elucidate potential‐dependent product distribution for the two catalysts, namely faradaic efficiency, is achieved. Accordingly, the nanoparticulate analog is significantly more active toward competitive hydrogen evolution reaction and 2‐MF production, whereas the polycrystalline sample is more selective toward furfuryl alcohol. The observed differences in ECH are ascribed to alterations in surface domains, which is supported by surface‐sensitive lead underpotential deposition characterization.