Ningkang Qian,Degong Ding,Liang Ji,Junjie Li,Hui Zhang,Deren Yang
Lattice engineering is a powerful strategy not only to optimize electrocatalytic performances, but also to deepen the understanding of electrocatalytic mechanisms. Lattice engineering can be effectively achieved in core–shell nanocrystals owing to the lattice mismatch of heterostructures. Herein, we constructed three kinds of icosahedra consisting of Au73Pd27@Pt, Au66Pd34@Pt and Pd@Pt core–(interlayer)–shell by a seed-mediated method. The introduction of an ultrathin Pd interlayer in the Au66Pd34@Pt icosahedra enables us to separately identify the strain effect and ligand effect. The specific activities towards the EOR of these icosahedra are in the sequence Au73Pd27@Pt > Au66Pd34@Pt > Pd@Pt, indicating that both the ligand effect and strain effect caused by Au can enhance the activity of Pt towards the EOR. The in situ FTIR studies confirm that the EOR processes on these icosahedra are all dominated by the C2 pathway, and hence we ascribe the enhancements of EOR activities to the faster kinetics of the C2 pathway by producing acetate or acetaldehyde.
Cuixia Bi,Xiaolong Yin,Zhixiu Wang,Hongyan Zhao,Guangqiang Liu
In this study, trimetallic Au@PdPt nanoparticles (NPs) were synthesized by a seed-mediated technique, possessing a hexoctahedral (HOH) Au core with a branched PdPt alloy shell. The fabrication process involved the synthesis of HOH Au NPs exhibiting high-index {651} facet as nanotemplates, followed by the epitaxial growth of Pd and Pt on these NPs to yield HOH Au@PdPt NPs. The size and composition of HOH Au@PdPt NPs as well as the thickness of PdPt alloy shells (from 2 to 4, 5, and 8 nm) can be precisely adjusted by varying the quantity of Pd and Pt precursors. The catalytic efficacy of these Au@PdPt NPs was significantly enhanced through the synergistic effect between Au, Pd, and Pt, along with the increased contact areas afforded by multibranched PdPt alloy shells. For methanol electro-oxidation, the catalytic activity of HOH Au@PdPt NPs depends on the Pt content showing a distinctive volcano-type pattern. Remarkably, the HOH Au@Pd0.3Pt0.3 NPs demonstrate optimum catalytic performance for methanol oxidation in acidic conditions, exhibiting superior electrocatalytic properties compared to commercial Pt black catalysts. Their ECSA value, mass, and specific activities are 47.21 m2 g–1, 0.93 A mg–1, and 1.97 mA cm–2, respectively. This research can be exploited to fabricate catalysts possessing exceptional properties by precisely designing and controlling the size, composition and morphology of the trimetallic Au@PdPt NPs.
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