Please cite this article as: Heiki Erikson, Madis Lüsi, Ave Sarapuu, Kaido Tammeveski, Jose Solla-Gullón, Juan M.Feliu, Oxygen electroreduction on carbon-supported Pd nanocubes in acid solutions, Electrochimica Acta http://dx.doi.org/10.1016/j.electacta. 2015.11.125 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Oxygen electroreduction on carbon-supported Pd nanocubes in acid solutions Highlights• Carbon-supported Pd nanocubes of three different size and loading were prepared• The specific activity for oxygen reduction reaction is independent of Pd content• Pd nanocubes possess higher specific activity for ORR than spherical Pd nanoparticles• The ORR on carbon-supported Pd nanocubes proceed mainly via 4-electron pathway• Tafel behaviour of ORR on carbon-supported Pd nanocubes is similar to that of bulk Pd AbstractThe oxygen reduction reaction (ORR) was studied on carbon-supported cubic palladium nanoparticles of different sizes (~30 nm, ~10 nm and ~7 nm). Cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) were used as capping agents to prepare the nanocubes and Pd content in the catalyst samples was 20 and 50 wt%. The surface morphology of the prepared materials was studied by transmission electron microscopy (TEM). The catalyst materials were electrochemically characterised by cyclic voltammetry and CO stripping experiments. The rotating disk electrode (RDE) method was employed for ORR studies in 0.5 M H 2 SO 4 and 0.1 M HClO 4 solutions. The ORR results revealed that the specific activity of cubic Pd nanoparticles is higher than that of spherical Pd particles and does not depend on the Pd content in the catalyst, but decreases with decreasing the size of Pd nanocubes. Mass activity of Pd nanocubes increased with decreasing the particle size. The ORR proceeds mainly via 4-electron pathway and the reaction mechanism is similar to that on bulk Pd.

Oxygen reduction reaction on carbon-supported palladium nanocubes in alkaline media, Electrochemistry Communications (2016Communications ( ), doi: 10.1016Communications ( /j.elecom.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractCarbon-supported Pd nanocubes with the size of 30, 10 and 7 nm were prepared and their electrocatalytic activity towards the oxygen reduction reaction (ORR) in alkaline solution was studied. For comparison carbon-supported spherical Pd nanoparticles and commercial Pd/C catalyst were used. The catalysts were characterised by transmission electron microscopy, electro-oxidation of carbon monoxide and cyclic voltammetry and the ORR activity was evaluated using the rotating disk electrode method. The ORR on all studied Pd/C catalysts proceeded via four-electron pathway where the rate-limiting step was the transfer of the first electron to O 2 molecule. The specific activity of Pd nanocubes was more than two times higher than that of spherical Pd nanoparticles and increased with increasing the particle size.

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