Highlights

Functionalized Aligned Carbon Nanotubes as Electrocatalyst for Fuel Cell Applications

Scientific Achievement

Our project aims at developing a novel membrane electrode assembly (MEA) using catalyst-decorated, vertically-aligned carbon nanotube (ACNT) layers as the electrode support.  The potential advantages of an ACNT-based MEA include improved thermal and charge transfers through the direct contact between the electrolyte and current collectors and maximum exposure of the catalyst site to gas reactant through uniform support geometry.

Excellent progress was made since the project inception; three major achievements are listed below:

(1) Methods of preparing dense, uniform ACNT layers with adjustable thickness were successfully developed using chemical vapor deposition (CVD) technique.

(2) A variety of solution impregnation methods were developed to catalyze ACNTs with good metal dispersion. A co-CVD process was developed to functionalize ACNT by directly depositing Pt through a gas phase reaction.

(3) MEA fabrication method was successfully developed to transfer ACNT to Nafion  membrane. The preliminary single cell tests demonstrated that ACNT-MEA showed improved mass-transport and power density over commercial product at equal or lower Pt loading.

Significance

ACNTs generated from the CVD process generally are highly hydrophobic. The current processes to deposit Pt on carbon black do not apply to ACNTs.  The catalyzing methods we developed can also be applied to other hydrophobic systems. 

This research is a brand new concept in the fuel cell research field. The objective of the proposal is to develop a novel aligned carbon nanotube based MEA and PEMFC with improved efficiency, lower or no Pt usage.  The project, if successful, will benefit significantly to the PEMFC manufacturers for automotive industry, as well as stationary and micro-power generation

The image acquired from SEM at EMC was featured as a cover page image for Argonne's FY2006 Annual Report.

This work has been published in Chem. Comm. 3, 329 (2008), Carbon 45, 2845 (2007); and presented at national and international conferences.

Performers