New-Concept CO-Tolerant Anode Catalysts Using a Rh Porphyrin-Deposited PtRu/C

作者：Yamazaki Shin ichi^*; Yao Masaru; Siroma Zyun; Ioroi Tsutomu; Yasuda Kazuaki

来源：Journal of Physical Chemistry C, 2010, 114(49): 21856-21860.

DOI：10.1021/jp107887x

CO poisoning of the Pt-based anodes (PtRu) of stationary proton exchange membrane fuel cells remains a severe problem for their realization. We tried to counteract this problem using a CO oxidation electrocatalyst. Rh porphyrins, which can catalyze electrochemical CO oxidation in low potential regions, were adsorbed on a carbon-supported PtRu catalyst (PtRu/C) to increase its CO tolerance. The combined electrocatalysts (Rh(porphyrin)-PtRu/C) exhibited significantly higher activity toward CO(2%)-contaminated H(2) than the PtRu/C alone; the onset potential for H(2) oxidation reaches 0.2 V (vs a reversible hydrogen electrode) on the combined catalyst. In contrast, the composite of PtRu black and Rh(porphyrin) scarcely exhibited CO tolerance. This suggests that the enhancement of CO tolerance in Rh(porphyrin)-PtRu/C is mainly caused by Rh porphyrins on carbon. The significance of Rh porphyrins on carbon was shown by the findings that a mixed catalyst composed of carbon-supported Rh(porphyrin) (Rh(porphyrin)/C) and PtRu/C gave high oxidation activity toward CO(2%)/H(2). Rh porphyrin on carbon would decrease the CO concentration around PtRu particles and thus reduce the CO poisoning of PtRu catalysts.

• 出版日期2010-12-16