In situ ion exchange preparation of Pt/carbon nanotubes electrode: Effect of two-step oxidation of carbon nanotubes

The in situ ion exchange method has been employed to prepare carbon nanotubes (CNT) supported Pt electrode, in which CNT is functionalized with two-step oxidation, namely electrochemical oxidation and chemical oxidation. X-ray photoelectron spectroscopy (XPS) confirms that two-step oxidation produces more carboxylic acid groups. Transmission electron microscopy (TEM) shows that Pt nanoparticles are highly dispersed on the CNT surface. Electrochemical measurements show that the resultant Pt/CNT electrode treated by two-step oxidation exhibits the largest electrochemical surface area and the highest activity for oxygen reduction reaction (ORR) among the investigated electrodes. This can be attributed to the fact that the two-step oxidation treatment produces more carboxylic acid groups which is the determining factor for Pt loading and dispersion via ion-exchange.

Two-step oxidation treatment, which involved both electrochemical oxidation and chemical oxidation, can produce more carboxylic acid groups at the electroactive sites on CNT surface, and result in loading more Pt nanoparticles in the following ion exchange process.Figure optionsDownload as PowerPoint slideHighlights
► Pt nanoparticles deposited via in situ ion exchange were highly dispersed on the CNT surface.
► Two-step oxidation treatment produced more carboxylic acid groups at the electroactive sites on CNT surface.
► Pt/CNT electrode treated by two-step oxidation exhibited the largest electrochemical surface area and the highest activity for oxygen reduction reaction (ORR) among the investigated electrodes.