Multi-walled carbon nanotubes (MWNTs) represent a promising support medium for electrocatalysts, especially Pt nanoparticles (NPs). The advantages of using MWNTs include their large surface area, high conductivity, as well as long-term stability. Surface functionalization of MWNTs with various terminal groups such as -COOH, -SH, and -NH<sub>2</sub> allows for rational electronic tuning of catalyst-support interactions. However, several issues still need to be addressed for such systems. First, catalysts have the tendency to aggregate and dissolve during the electrochemical procedure. Second, the covalent functionalization treatment of MWNTs adopted by most groups tends to lead to a loss of structural integrity of the nanotubes (NTs). To mitigate for all of these issues, we have utilized two different attachment approaches (i.e. covalent versus non-covalent) to functionalize the outer walls of pristine MWNTs and we compared the catalytic performance of as-deposited ultrathin (&lt; 2 nm) 1D Pt nanowires with that of conventional Pt NPs towards the oxygen reduction reaction (ORR). Our results have demonstrated that the electrochemical activity of as-prepared Pt NW/functionalized-CNT heterostructures could be dramatically improved by using ultrathin Pt nanowires (instead of NPs) with non-covalently (as opposed to covalently) functionalized CNT supports. Spectroscopic evidence corroborated the definitive presence of charge transfer between the metal catalysts and the underlying NT support, whose direction and magnitude are a direct function of (i) the terminal chemistry as well as (ii) the attachment methodology, all of which simultaneously impact upon the observed electrocatalytic performance. Specifically, the use of a non-covalent π-π stacking method coupled with a -COOH terminal moiety yielded the highest performance results, reported to date, for any similar system consisting of Pt (commercial NPs or otherwise) deposited onto carbon-based supports, a finding of broader interest towards the fabrication of high-performing electrocatalysts in general.<br/>

Chemical strategies for enhanced oxygen reduction reaction activity in ultrathin Pt nanowires supported by functionalized carbon nanotubes

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.