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.
This work entails a comprehensive study on PtPd, and PdPt bimetallic nanoparticles (BNPs) supported on Vulcan XC‐72 carbon towards methanol oxidation reaction (MOR) in alkaline media. BNPs with different compositions were synthesized using a flexible and facile polyol method through a heterogeneous nucleation process. The homogeneous BNPs were characterized by SEM, XRD, HR‐TEM and XRF to analyse the crystallographic structure and verified the controlled characteristics. The electrochemical properties and stability were investigated using cyclic voltammetry and chronoamperometry, respectively. As a consequence of the electrocatalysts’ controlled composition, a direct correlation between the catalytic activity and the shift in the PtO/PdO reduction potential was observed. The optimal electrocatalyst that overcomes the catalytic performance of PdPt structure, also showed an improvement in the CO anti‐poisoning ability was PtPd (1 : 0.5)/C with a current density of 12.56‐fold higher than of commercial Pt/C. This study about different Pt/Pd structures may provide valuable information for developing new and efficient electrocatalysts towards MOR.
Direct alcohol fuel cells are claiming to be one of the primary clean power sources to attain a sustainable future. In the present study, PtPd core-shell bimetallic nanoparticles (CSNPs) were synthesized by the polyol method. The shell was adjusted by adding an increased amount of Pd precursor on presynthesized Pt nanoparticles. The morphology and atomic structure of the PtPd CSNPs were characterized by X-ray diffraction and high-resolution scanning transmission electron microscopy. PtPd CSNPs were successfully supported on Vulcan XC-72 carbon and verified by scanning electron microscopy.The electrocatalysts were tested by cyclic voltammetry in an alkaline medium for the activity performance to ethanol oxidation reaction. The stability along with the presence of poisoning carbonaceous species was investigated by chronoamperometry and voltammetry cycles. Also, the cyclic durability was analysed. The results confirmed that the catalytic performance depends on the elemental composition of PtPd CSNPs, showing the optimum catalytic properties to PtPd (1 : 0.5)/C than commercial Pt/C.
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