Xingqiao Wu,Qingfeng Xu,Yucong Yan,Jingbo Huang,Xiao Li,Yi Jiang,Hui Zhang,Deren Yang
Pd@Pt core–shell nanocrystals with ultrathin Pt layers have received great attention as active and low Pt loading catalysts for oxygen reduction reaction (ORR). However, the reduction of Pd loading without compromising the catalytic performance is also highly desired since Pd is an expensive and scarce noble-metal. Here we report the epitaxial growth of ultrathin Pt shells on PdxCu truncated octahedra by a seed-mediated approach. The Pd/Cu atomic ratio (x) of the truncated octahedral seeds was tuned from 2, 1 to 0.5 by varying the feeding molar ratio of Pd to Cu precursors. When used as catalysts for ORR, these three PdxCu@Pt core–shell truncated octahedra exhibited substantially enhanced catalytic activities compared to commercial Pt/C. Specifically, Pd2Cu@Pt catalysts achieved the highest area-specific activity (0.46 mA cm−2) and mass activity (0.59 mA μgPt−1) at 0.9 V, which were 2.7 and 4.5 times higher than those of the commercial Pt/C. In addition, these PdxCu@Pt core–shell catalysts showed a similar durability with the commercial Pt/C after 10 000 cycles due to the dissolution of active Cu and Pd in the cores.
Reducing Pt loading, while improving electrocatalytic activity and the stability of Pt-based nanostructured materials, is currently a key challenge in green energy technology. Herein, we report the controllable synthesis of tri-metallic (Au@Ag@Pt) and bimetallic (Ag@Pt) particles consisting of a controllable thin Pt shell, via interface-mediated galvanic displacement. Through oil-ethanol-H 2 O interface mediation, the controllable “out to in” displacement of Ag atoms to Pt enables the formation of a thin Pt shell on monodisperse sub-ten-nanometer Au@Ag and Ag nanocrystals. The synthesized nanoparticles with a thin Pt shell exhibited potential catalytic activity towards the oxygen reduction reaction (ORR) due to the high exposure of Pt atoms.
Ji Zhou,Chen Liu,Yifei Liao,Guanghui Xia,Qin Huang,Yisha Huang,Yigang Yan,Chaoling Wu,Yao Wang
Catalysts with a platinum-rich shell and intermetallic core are considered to be one of the most promising catalysts for the oxygen reduction reaction (ORR) in fuel cells. However, too thin of a platinum-rich shell makes the core–shell structure easy to lose. Therefore, the development of the core–shell structure with an appropriate thickness of platinum-rich shell and intermetallic core remains a huge challenge in the field of fuel cells. In this paper, PtCoN-1000/C catalyst with about 1 nm thick platinum-rich shell shows significantly enhanced ORR activity and stability in acidic electrolyte, which is superior to L10-PtCo/C and commercial Pt/C catalysts. The specific power at 0.8 V and mass activity at 0.9 V are 5.60 W mgPt–1 and 0.74 A mgPt–1, respectively. It suggests that the tensile strain and moderately thickened platinum-rich shell led by nitrogen doping can greatly improve the performance of the catalyst.
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