Synthesis of Au@Pt Core—Shell Nanoparticles as Efficient Electrocatalyst for Methanol Electro-Oxidation

Abstract

Bimetallic Au@Pt nanoparticles (NPs) with Pt monolayer shell are of much interest for applications in heterogeneous catalysts because of enhanced catalytic activity and very low Pt-utilization. However, precisely controlled synthesis with uniform Pt-monolayers and stability on the AuNPs seeds remain elusive. Herein, we report the controlled deposition of Pt-monolayer onto uniform AuNPs seeds to obtain Au@Pt core–shell NPs and their Pt-coverage dependent electrocatalytic activity for methanol electro-oxidation. The atomic ratio between Au/Pt was effectively tuned by varying the precursor solution ratio in the reaction solution. The morphology and atomic structure of the Au@Pt NPs were analyzed by high-resolution scanning transmission electron microcopy (HR-STEM) and X-ray diffraction (XRD) techniques. The results demonstrated that the Au@Pt core–shell NPs with Pt-shell thickness (atomic ratio 1:2) exhibit higher electrocatalytic activity for methanol electro-oxidation reaction, whereas higher and lower Pt ratios showed less overall catalytic performance. Such higher catalytic performance of Au@Pt NPs (1:2) can be attributed to the weakened CO binding on the Pt/monolayers surface. Our present synthesis strategy and optimization of the catalytic activity of Au@Pt core–shell NPs catalysts provide promising approach to rationally design highly active catalysts with less Pt-usage for high performance electrocatalysts for applications in fuel cells.

Characterization and Electrocatalytic Features of PtPd and PdPt Bimetallic Nanoparticles for Methanol Electro‐oxidation

“…All the synthesized nanoparticles showed a homogeneous particle size distribution, and no aggregates and agglomeration are observable. In addition, figure S4 shows the histogram distribution plots, where varying the Pt/Pd ratio (1 : 0.5, 1 : 1, and 1 : 3), the average particle size slightly increases, this is related to an increase of the thickness of Pd layers [29] . In the same way, Pd and PdPt BNPs showed a homogeneous particle size similar to PtPd BNPs (Figure S5).…”

Enhancing the Hydrogen-Sensing Performance of p-Type PdO by Modulating the Conduction Model

“…The X-ray diffraction (XRD) patterns of Au@PdO NAs before and after treatment by NaBH 4 for different times are shown in Figure C. The diffraction peaks at 33.8, 42.1, 54.9, 60.4, 60.8, and 71.4° correspond to the (101), (110), (112), (103), (200), and (211) planes of the PdO shell, , and the remaining four characteristic diffraction peaks correspond to the (111), (200), (220), and (311) planes of the Au core . After being reduced by NaBH 4 , a new characteristic diffraction peak at 40.1° appears, which should be assigned as the Pd (111) plane, and the peak becomes intensive along with the increase of the reduction time.…”

Recent Advances in Bio‐Templated Metallic Nanomaterial Synthesis and Electrocatalytic Applications

“…In bimetallic systems, the introduction of a second metal generally gives a number of new effects: [188] 1) different Fermi levels of the two metals can lead to charge transfer and alter the electronic properties of the material; [189,190] and 2) the intimate interactions between the two components may affect the final size, shape and spatial arrangement of surface atoms, [191] which will further impact the catalyst performance. One good example of bimetallic catalysts is AuPt NMs, which have been discovered to be effective electrocatalysts in a series of applications such as ORR, [192–194] HER [195–197] and MOR [198–200] . However, precise control of the surface properties in such systems still presents a large challenge in bimetallic nanostructures.…”