title: Synthesis of Pd-Pt bimetallic nanocrystals with a concave structure through a bromide-induced galvanic replacement reaction.
abstract: This article describes a systematic study of the galvanic replacement reaction between PtCl(6)(2-) ions and Pd nanocrystals with different shapes, including cubes, cuboctahedrons, and octahedrons. It was found that Br(-) ions played an important role in initiating, facilitating, and directing the replacement reaction. The presence of Br(-) ions led to the selective initiation of galvanic replacement from the {100} facets of Pd nanocrystals, likely due to the preferential adsorption of Br(-) ions on this crystallographic plane. The site-selective galvanic replacement resulted in the formation of Pd-Pt bimetallic nanocrystals with a concave structure owing to simultaneous dissolution of Pd atoms from the {100} facets and deposition of the resultant Pt atoms on the {111} facets. The Pd-Pt concave nanocubes with different weight percentages of Pt at 3.4, 10.4, 19.9, and 34.4 were also evaluated as electrocatalysts for the oxygen reduction reaction (ORR). Significantly, the sample with a 3.4 wt.% of Pt exhibited the largest specific electrochemical surface area and was found to be four times as active as the commercial Pt/C catalyst for the ORR in terms of equivalent Pt mass.
authors: Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, United States.
authors: Hui
authors: H
authors: Zhang
authors: Mingshang
authors: M
authors: Jin
authors: Jinguo
authors: J
authors: Wang
authors: Weiyang
authors: W
authors: Li
authors: Pedro H C
authors: PH
authors: Camargo
authors: Moon J
authors: MJ
authors: Kim
authors: Deren
authors: D
authors: Yang
authors: Zhaoxiong
authors: Z
authors: Xie
authors: Younan
authors: Y
authors: Xia
mesh_terms: D001965:Bromides / Q000737:chemistry*; D002384:Catalysis; D055664:Electrochemical Techniques; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology; D010165:Palladium / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*
chemical_list: D001965:Bromides; D010984:Platinum; D010165:Palladium