Identical-Location Scanning Electron Microscopy Observation of Surface Morphological Changes of Pt–Cu Nanoparticles

Abstract

The surface morphological changes of electrodeposited Pt75 at% Cu (Pt75Cu) nanoparticles under potential cycling were investigated by identical-location scanning electron microscopy. The electrodeposited nanoparticles consisted of numerous nuclei (³3 nm in diameter) that agglomerated to form larger secondary particles (3050 nm). Upon immersion in sulfuric acid, Pt shells formed on the surfaces of the Pt75Cu nanoparticles due to the selective dissolution of Cu. Although around 40% of the Cu was dissolved from Pt75Cu, no noticeable surface morphological changes were observed. Thereafter, Pt75Cu was subjected to potential cycling between 0.05 and 1.0 V, whereupon surface smoothing of the nanoparticles due to the surface diffusion of Pt was observed. Conversely, when Pt75Cu was potential-cycled between 0.05 and 1.4 V, the particle diameters of the nanoparticles drastically decreased and the nuclei on the surface completely disappeared owing to Pt dissolution and re-deposition. The heat-treated nanoparticles developed numerous pores on their surfaces during immersion and the initial stage of potential cycling. However, their final morphologies were found to be similar to those of the non-heated sample. The formation of pores can be explained by the coarsening of nuclei by heat treatment.

High-corrosion-resistance mechanism of graphitized platelet-type carbon nanofibers in the OER in a concentrated alkaline electrolyte

“…S2 †). [57][58][59][60][61] The size reduction of each nanoparticle and nanober by carbon corrosion was measured by comparing the SEM images before and aer polarization. The carbon nanoparticles and nanobers were deposited on a surfaceroughened Au TEM grid (Fig.…”

Best Papers Awarded in 2021 by <i>Materials Transactions</i>

“…10 (2020) pp. 19491957) 10,15) Platinum and transition-metal (PtM) alloys have attracted attention as polymer electrolyte fuel cells (PEFCs) catalysts because of their higher oxygen reduction reaction activity than Pt. 73,74) However, the dissolution of both Pt and M leads to a performance loss of PEFCs.…”

“…73,74) However, the dissolution of both Pt and M leads to a performance loss of PEFCs. 75) In this study, 10,15) the surface morphological changes of electrodeposited Pt75 at% copper (Pt75Cu) nanoparticles due to dissolutions under potential cycling between 0.051.4 V (vs. standard hydrogen electrode) mimicking PEFCs operating conditions were investigated by identical-location field emission scanning electron microscopy (IL-FE-SEM). Figures 9(a), (c), and (e) are FE-SEM images of the heat-treated Pt75Cu nanoparticles before experiments.…”

“…(This is a national project started in 2018 for 5 years with the support by Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan.) Besides the 4 awarded papers associated with the highentropy alloys, readers can find two papers are for shape memory alloys, 4,11) two for microstructural analyses by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), 4,10) two for simulations 5,6) and two for Mg alloys. 11,12) It should be noted that SEM and TEM are useful tools for microstructural analyses and often become important topics in advanced research areas.…”