Oleylamine Aging of PtNi Nanoparticles Giving Enhanced Functionality for the Oxygen Reduction Reaction

• DOI: 10.1021/acs.nanolett.1c00706
• Publication Date: 2021-04-26T13:51:37Z
• Authors: Gerard M. Leteba; Yi-Chi Wang; Thomas J. A. Slater; Rongsheng Cai; Conor Byrne; Christopher P. Race; David R. G. Mitchell; Pieter B. J. Leve...; Neil P. Young; Stuart M. Holmes; Alex Walton; Angus I. Kirkland; Sarah J. Haigh; Candace I. Lang
• Keywords: Condensed Matter - Materials Science; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; Physics - Applied Physics; Applied Physics (physics.app-ph); 02 engineering and technology; 01 natural sciences; 0104 chemical sciences; ResearchInstitutes_Networks_Beacons/dalton_nuclear_institute; name=Dalton Nuclear Institute; 0210 nano-technology

We report a rapid solution-phase strategy to synthesize alloyed PtNi nanoparticles which demonstrate outstanding functionality for the oxygen reduction reaction (ORR). This one-pot co-reduction colloidal synthesis results in a monodisperse population of single-crystal nanoparticles of rhombic dodecahedral morphology, with Pt enriched edges and compositions close to Pt1Ni2. We use nanoscale 3D compositional analysis to reveal for the first time that oleylamine (OAm)-aging of the rhombic dodecahedral Pt1Ni2 particles results in Ni leaching from surface facets, producing aged particles with concave faceting, an exceptionally high surface area and a composition of Pt2Ni1. We show that the modified atomic nanostructures catalytically outperform the original PtNi rhombic dodecahedral particles by more than 2-fold and also yield improved cycling durability. Their functionality for the ORR far exceeds commercially available Pt/C nanoparticle electrocatalysts, both in terms of mass-specific activities (up to a 25-fold increase) and intrinsic area-specific activities (up to a 27-fold increase).<br/>14 pages, 4 figures, supplementary information<br/>