Title: Chemical Strategies for Enhancing Activity and Charge Transfer in Ultrathin Pt Nanowires Immobilized onto Nanotube Supports for the Oxygen Reduction Reaction

Abstract

Multiwalled 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 -NH₂, allows for rational electronic tuning of catalyst–support interactions. But, several issues still need to be addressed for such systems. Over the course of an electrochemical run, catalyst durability can decrease, due in part to metal NP dissolution, a process facilitated by the inherently high surface defect concentration within the support. Second, the covalent functionalization treatment of MWNTs adopted by most groups tends to lead to a loss of structural integrity of the nanotubes (NTs). In order to mitigate for all of these issues, we have utilized two different attachment approaches (i.e., covalent versus noncovalent) to functionalize the outer walls of pristine MWNTs and compared the catalytic performance of as-deposited ultrathin (<2 nm) 1D Pt nanowires with that of conventional Pt NPs toward the oxygen reduction reaction (ORR). Our results demonstrated that the electrochemical activity of Pt nanostructures immobilized onto functionalized carbon nanotube (CNT) supports could be dramatically improved by using ultrathin Pt nanowires (insteadmore » of NPs) with noncovalently (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, both of which simultaneously impact upon the observed electrocatalytic performance. Specifically, the use of a noncovalent 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 toward the fabrication of high-performing electrocatalysts in general.« less

Authors:

Li, Luyao ^[1]; Liu, Haiqing ^[1]; Wang, Lei ^[1]; Yue, Shiyu ^[1]; Tong, Xiao ^[2]; Zaliznyak, Tatiana ^[3]; Taylor, Gordon T. ^[3]; Wong, Stanislaus S.  ^[4]

• Search DOE PAGES for author "Wong, Stanislaus S."
• Search DOE PAGES for ORCID "0000-0001-7351-0739"

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+ Show Author Affiliations

1. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, United States
2. Center for Functional Nanomaterials, Building 735, Brookhaven National Laboratory, Upton, New York 11973, United States
3. School of Marine and Atmospheric Sciences, State University of New York at Stony Brook, Stony Brook, New York 11794-5000, United States
4. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, United States, Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Building 480, Upton, New York 11973, United States

Publication Date:

Mon Dec 12 00:00:00 EST 2016

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1336964

Alternate Identifier(s):

OSTI ID: 1338606

Report Number(s):

BNL-113311-2016-JA
Journal ID: ISSN 1944-8244

Grant/Contract Number:  

SC-00112704; SC00112704

Resource Type:

Published Article

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Name: ACS Applied Materials and Interfaces Journal Volume: 8 Journal Issue: 50; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; charge transfer; functionalized carbon nanotubes; noncovalent attachment; oxygen reduction reaction; Pt ultrathin nanowires