Details

Autor(en) / Beteiligte

• Matin, Md. Abdul
• Lee, Junsu
• Kim, Gwan Woo
• Park, Hyun-Uk
• Cha, Byeong Jun
• Shastri, Sarvjit
• Kim, Gunn
• Kim, Young-Dok
• Kwon, Young-Uk
• Petkov, Valeri

Titel

Morphing Mncore@Ptshell nanoparticles: Effects of core structure on the ORR performance of Pt shell

Ist Teil von

• Applied catalysis. B, Environmental, 2020-06, Vol.267 (C), p.118727, Article 118727

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Disordered bcc-like Mn core of Mn@xPt nanoparticles induces strong compressive stresses in Pt shell resulting in very large enhancement of ORR activity over pure Pt nanoparticles. [Display omitted] •One-step sonochemical reactions produce a series of Mn@xPt (x = 1, 1.5, 2) core-shell nanoparticles.•Analysis data indicate that the shell thickness of Mn@xPt nanoparticles systematically varies from 1 to 2 atomic layers.•Structural refinements on the X-ray diffraction data provide 3D structures of Mn@xPt nanoparticles with atomic details.•Mn@xPt nanoparticles are composed of bcc-like Mn core and fcc Pt shell, because of which the Pt shell is heavily strained.•The large ORR enhancements of Mn@xPt from that of pure Pt can be well-accounted for by their 3D structures. Currently, the catalysts performance for the oxygen reduction reaction (ORR) is limited by two major factors, their price and the scaling relationship, i.e. constant offset, between the binding energy of reactants and reaction intermediates. Here we show that both limitations may be eased by using nanoparticle catalysts composed of a core of earth-abundant Mn and Pt shell of two atomic layers. The unusual atomic-structure of Mn core renders the distribution of coordination numbers and related atomic-level stresses on the Pt shell very broad in comparison to pure Pt particles. This increases the chances of nearby sites on the shell to affect each other’s activity such that the dissociative absorption of molecular oxygen is facilitated without correspondingly increasing the binding strength of reaction intermediates, thereby promoting the ORR kinetics. Our findings introduce the concept of structural flexibility of the 3d-metal core and 5d-Pt shell as a strategy for catalysis performance.