Oxygen electroreduction on small (<10 nm) and {100}-oriented Pt nanoparticles. (20th January 2022)

• Record Type: Journal Article
• Authors: Erikson, Heiki; Antoniassi, Rodolfo M.; Solla-Gullón, Jose; Torresi, Roberto M.; Tammeveski, Kaido; Feliu, Juan M.
• Is Part Of: Electrochimica acta. Volume 403(2022)
• Publication Date: 2022-01-20
• Subjects: Oxygen reduction reaction -- Electrocatalysis -- Pt nanocubes -- Pt nanoparticles -- Supported electrocatalyst; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.139631
• Languages: English
• ISSNs: 0013-4686

Abstract

Research highlights: ORR on small <10 nm Pt nanocubes proceed mainly via a 4 e – pathway Mass-activities for ORR increase with decreasing the particle size The 4.6 nm carbon-supported {100}-oriented Pt NPs had optimal properties for ORR The ORR mechanism does not change when decreasing Pt particle size from 7 to 3.1 nm Abstract: Oxygen reduction reaction (ORR) was studied on {100}-oriented Pt nanoparticles with sizes from 3 to 7 nm in sulphuric acid solution. The distribution and size of nanoparticles was analysed by transmission electron microscopy and metal loading was determined by inductively coupled plasma optical emission spectroscopy. The synthesised nanoparticles have about 40% of Pt(100) facet and 10% Pt(111) as determined from Ge and Bi adsorption, respectively. The four Pt/C catalysts with metal loading from 25 to 38 wt% were tested for ORR activity in 0.5 M H2 SO4 solution using the rotating disk electrode method. It was found that the ORR proceeds mainly via a 4-electron pathway with the rate-limiting step being the transfer of the first electron to O2 molecule. The mass activities for ORR increase with decreasing the particle size, but specific activity has a maximum at 4.6 nm particle size. This means the most optimal {100}-oriented Pt size for ORR is around 4.6 nm in sulphuric acid solution.