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Preparation of a platinum electrocatalyst by coaxial pulse arc plasma deposition

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ABSTRACT

We have developed a new method of preparing Pt electrocatalysts through a dry process. By coaxial pulse arc plasma deposition (CAPD), highly ionized metal plasma can be generated from a target rod without any discharged gases, and Pt nanoparticles can be deposited on a carbon support. The small-sized Pt nanoparticles are distributed over the entire carbon surface. From transmission electron microscopy (TEM), the average size of the deposited Pt nanoparticles is estimated to be 2.5 nm, and their size distribution is narrow. Our electrocatalyst shows considerably improved catalytic activity and stability toward methanol oxidation reaction (MOR) compared with commercially available Pt catalysts such as Pt black and Pt/carbon (PtC). Inspired by its very high efficiency toward MOR, we also measured the catalytic performance for oxygen reduction reaction (ORR). Our PtC catalyst shows a better performance with half-wave potential of 0.87 V, which is higher than those of commercially available Pt catalysts. The higher performance is also supported by a right-shifted onset potential. Our preparation is simple and could be applied to other metallic nanocrystals as a novel platform in catalysis, fuel cells and biosensors.

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Cyclic voltammograms for MOR catalyzed (a) PtC-CAPD, (b) PtC-5%, (c) PtC-20% and (d) PtB catalysts, respectively, in a 0.5 M H2SO4 solution containing 0.5 M methanol at different stages.
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Figure 4: Cyclic voltammograms for MOR catalyzed (a) PtC-CAPD, (b) PtC-5%, (c) PtC-20% and (d) PtB catalysts, respectively, in a 0.5 M H2SO4 solution containing 0.5 M methanol at different stages.

Mentions: In addition to the catalytic activity, the durability of Pt catalysts is also a very important factor for practical usage. Both the activity and the durability were investigated by using chronoamperometric curves at 0.5 V for 2000 s (figure 3(b)). The current density of our Pt catalyst than the other samples. For each sample, the initial current density gradually decreased, and finally reach a plateau with a stable current value. In addition to the highest initial activity, our Pt catalyst retains superior current density even after 2000 s (table 1). Even when the applied potential was changed to 0.4 V, the activities of different Pt catalysts are in the same order (figure 3(c)). After 2000 s, MOR performance was evaluated (figure 4, table 1). As clearly seen from table 1, when the potential is 0.4 V, MOR activity loss is only 11.1% for the PtC-CAPD catalyst, which is significantly lower compared to PtB (57.1%), PtC-5% (12.0%) and PtC-20% (21.2%). This further testifies that our Pt catalyst exhibits superior electrocatalytic performance of the MOR.


Preparation of a platinum electrocatalyst by coaxial pulse arc plasma deposition
Cyclic voltammograms for MOR catalyzed (a) PtC-CAPD, (b) PtC-5%, (c) PtC-20% and (d) PtB catalysts, respectively, in a 0.5 M H2SO4 solution containing 0.5 M methanol at different stages.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036468&req=5

Figure 4: Cyclic voltammograms for MOR catalyzed (a) PtC-CAPD, (b) PtC-5%, (c) PtC-20% and (d) PtB catalysts, respectively, in a 0.5 M H2SO4 solution containing 0.5 M methanol at different stages.
Mentions: In addition to the catalytic activity, the durability of Pt catalysts is also a very important factor for practical usage. Both the activity and the durability were investigated by using chronoamperometric curves at 0.5 V for 2000 s (figure 3(b)). The current density of our Pt catalyst than the other samples. For each sample, the initial current density gradually decreased, and finally reach a plateau with a stable current value. In addition to the highest initial activity, our Pt catalyst retains superior current density even after 2000 s (table 1). Even when the applied potential was changed to 0.4 V, the activities of different Pt catalysts are in the same order (figure 3(c)). After 2000 s, MOR performance was evaluated (figure 4, table 1). As clearly seen from table 1, when the potential is 0.4 V, MOR activity loss is only 11.1% for the PtC-CAPD catalyst, which is significantly lower compared to PtB (57.1%), PtC-5% (12.0%) and PtC-20% (21.2%). This further testifies that our Pt catalyst exhibits superior electrocatalytic performance of the MOR.

View Article: PubMed Central - PubMed

ABSTRACT

We have developed a new method of preparing Pt electrocatalysts through a dry process. By coaxial pulse arc plasma deposition (CAPD), highly ionized metal plasma can be generated from a target rod without any discharged gases, and Pt nanoparticles can be deposited on a carbon support. The small-sized Pt nanoparticles are distributed over the entire carbon surface. From transmission electron microscopy (TEM), the average size of the deposited Pt nanoparticles is estimated to be 2.5 nm, and their size distribution is narrow. Our electrocatalyst shows considerably improved catalytic activity and stability toward methanol oxidation reaction (MOR) compared with commercially available Pt catalysts such as Pt black and Pt/carbon (PtC). Inspired by its very high efficiency toward MOR, we also measured the catalytic performance for oxygen reduction reaction (ORR). Our PtC catalyst shows a better performance with half-wave potential of 0.87 V, which is higher than those of commercially available Pt catalysts. The higher performance is also supported by a right-shifted onset potential. Our preparation is simple and could be applied to other metallic nanocrystals as a novel platform in catalysis, fuel cells and biosensors.

No MeSH data available.


Related in: MedlinePlus