Abstract
Bimetallic nanostructured core-shell structures are commonly used as catalysts in a wide variety of reactions. We surmised that the addition of an additional metal would potentially allow catalytic tailoring with the possibility of an increase in activity. Here a tri-metallic catalytic structure, consisting of clustered catalytic Pt on the surface of a Pd shell supported on a rod shaped Au core was fabricated. The significance of the additional metallic component is shown by comparative electrochemically active surface area (ECSA) analysis results for the trimetallic Aurod-Pdshell-Ptcluster, bimetallic Aurod-Ptcluster and monometallic JM-Pt (used as a reference), which have respective ECSA values (cm2/mgPt) of 1883.0, 1371.7 and 879. The potential utility of the trimetallic catalysts was shown in a hydrogen peroxide sensing protocol, which showed the catalyst to have a sensitivity of 604 ìA/mMcm2 within a linear range of 0.0013–6.191 mM.
Highlights
The resulting nanoparticles were characterized by X-ray diffraction (XRD), UV-vis, Transmission electron microscopy (TEM), and XPS
From the TEM images, we can see that the core–shell nanostructures consist of Au rod-like cores with a Pd coating, upon which a coating comprising Pt clusters is deposited, Figure 2e,f
The XRD peak positions of the core-shell nanoparticles carrying the Pt clusters are similar to those of the core-shelled nanoparticles because the particle size of the Pt clusters is too small to give a distinct diffraction peak; the presence of Pt is confirmed by a Pt(111) shoulder which is apparent on the Au(111) peak
Summary
Catalysts incorporating metals with high catalytic ability, typically palladium and platinum, incur cost-penalties due to the scarcity of the active metal component; structures that efficiently employ a minimal amount of material, while retaining high catalytic efficiency, are highly sought after. Core-shell structured catalysts, formulated to contain only small amounts of palladium and platinum, have been used in a range of catalytic applications [1]. It was shown that the addition of Pt and Au to palladium promoted the methane oxidation activity, as well as improved the long-term stability compared to the monometallic Pd catalyst. In this study a tri-metallic structure was sequentially fabricated with the initial stage being the deposition of Pd on Au rods to give a Aurod-Pdshell support for the later deposition of Pt: the ability to exploit high surface area to mass ratios of precious metals by using thin coating confers both enhanced activity/selectivity and considerable materials cost savings [4,5,9]. New approaches leading to the development of robust and sensitive H2O2 sensors remain an ongoing quest
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