title: A density functional theory approach to mushroom-like platinum clusters on palladium-shell over Au core nanoparticles for high electrocatalytic activity.
abstract: Recently, it was found that Pt clusters deposited on Pd shell over Au core nanoparticles (Au@Pd@Pt NPs) exhibit unusually high electrocatalytic activity for the electro-oxidation of formic acid (P. P. Fang, S. Duan, et al., Chem. Sci., 2011, 2, 531-539). In an attempt to offer an explanation, we used here carbon monoxide (CO) as probed molecules, and applied density functional theory (DFT) to simulate the surface Raman spectra of CO at this core-shell-cluster NPs with a two monolayer thickness of Pd shell and various Pt cluster coverage. Our DFT results show that the calculated Pt coverage dependent spectra fit the experimental ones well only if the Pt clusters adopt a mushroom-like structure, while currently the island-like structure is the widely accepted model, which follows the Volmer-Weber growth mode. This result infers that there should be a new growth mode, i.e., the mushroom growth mode as proposed in the present work, for Au@Pd@Pt NPs. We suggest that such a mushroom-like structure may offer novel active sites, which accounts for the observed high electrocatalytic activity of Au@Pd@Pt NPs.
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces and LIA CNRS XiamENS NanoBioChem, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
authors.forename: Sai
authors.initials: S
authors.lastname: Duan
authors.forename: Ping-Ping
authors.initials: PP
authors.lastname: Fang
authors.forename: Feng-Ru
authors.initials: FR
authors.lastname: Fan
authors.forename: Ian
authors.initials: I
authors.lastname: Broadwell
authors.forename: Fang-Zu
authors.initials: FZ
authors.lastname: Yang
authors.forename: De-Yin
authors.initials: DY
authors.lastname: Wu
authors.forename: Bin
authors.initials: B
authors.lastname: Ren
authors.forename: Christian
authors.initials: C
authors.lastname: Amatore
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Xin
authors.initials: X
authors.lastname: Xu
authors.forename: Zhong-Qun
authors.initials: ZQ
authors.lastname: Tian
mesh_terms: D004563:Electrochemistry; D005561:Formates / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D005561:Formates; C030544:formic acid; D010984:Platinum; D010165:Palladium; D006046:Gold