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A Facile Preparation of Hollow Palladium Nanosphere Catalysts for Direct Formic Acid Fuel Cell

2009; American Chemical Society; Volume: 113; Issue: 24 Linguagem: Inglês

10.1021/jp902713k

1932-7455

Zhengyu Bai, Lin Yang, Lei Li, Jing Lv, Kui Wang, Jie Zhang,

Conducting polymers and applications

A facile and low-cost preparation of a polypyrrole-modified Vulcan XC-72 carbon-supported Pd/PPy−XC-72 hollow nanosphere catalyst was introduced in this paper. To increase the stability and utilization ratio of the catalyst, a two-step strategy was employed, which included the synthesis of a polypyrrole−carbon composite and the preparation of a hollow nanosphere catalyst. Co nanoparticles as sacrificial templates were deposited on the prepared polypyrrole−carbon composites by chemical reduction, and then Pd hollow nanospheres formed through the surface replacement reaction between the surface of Co nanoparticles and PdCl2 at room temperature. The novel Pd/PPy−XC-72 hollow nanosphere catalyst was 30−40 nm in diameter and 3−4 nm in shell thickness. FT-IR and TGA characterizations confirmed the existence and content of polypyrrole in the catalysts. The catalysts with 40 and 20% Pd showed a very high electrochemically active surface area and significant increase in electrocatalytic activity toward formic acid oxidation, which make them the preferable catalysts for direct formic acid fuel cells.