Atomically thin Pt shells on Au nanoparticle cores: facile synthesis and efficient synergetic catalysis

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2016-01, Vol.4 (9), p.3278-3286
• Main Authors: Engelbrekt, C, Šešelj, N, Poreddy, R, Riisager, A, Ulstrup, J, Zhang, J
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts; Fuels; Gold; Methyl alcohol; Nanostructure; Platinum; Synthesis
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta08922k

We present a facile synthesis protocol for atomically thin platinum (Pt) shells on top of gold (Au) nanoparticles (NPs) (Au@PtNPs) in one pot under mild conditions. The Au@PtNPs exhibited remarkable stability (> 2 years) at room temperature. The synthesis, bimetallic nanostructures and catalytic properties were thoroughly characterized by ultraviolet-visible light spectrophotometry, transmission electron microscopy, nanoparticle tracking analysis and electrochemistry. The 8 ± 2 nm Au@PtNPs contained 24 ± 1 mol% Pt and 76 ± 1 mol% Au corresponding to an atomically thin Pt shell. Electrochemical data clearly show that the active surface is dominated by Pt with a specific surface area above 45 m 2 per gram of Pt. Interactions with the Au core increase the activity of the Pt shell by up to 55% and improve catalytic selectivity compared to pure Pt. The Au@Pt NPs show exciting catalytic activity in electrooxidation of sustainable fuels ( i.e. formic acid, methanol and ethanol), and selective hydrogenation of benzene derivatives. Especially high activity was achieved for formic acid oxidation, 549 mA (mg Pt ) −1 (at 0.6 V vs. SCE), which is 3.5 fold higher than a commercial < 5 nm PtNP catalyst. Excellent activity for the direct production of γ-valerolactone, an alternative biofuel/fuel additive, from levulinic acid and methyl levulinate was finally demonstrated. Atomically thin platinum shells on gold nanoparticles (NPs) are synthesized in one pot under mild conditions. The core-shell NPs exhibit excellent catalysis for energy related processes such as electrochemical oxidation of biofuels, aromatic ring hydrogenation, and γ-valerolactone production.