Nano technologies -
A Direct Strategy for Producing Carbon-Nanotube-Based
Electrocatalytic Electrodes
Introduction
Fabrication of pre-existing carbonaceous
electrode materials for electrocatalysis is inherently
difficult to control, since it involves a multi-step
process and requires surface activation, chemical modification
or heat treatment, and/or other processing steps. Additionally,
the loading of noble metal-based catalysts generally
occurs as a secondary step either by physical, chemical,
or electrochemical deposition methods.
Invention Description
The method proposed avoids the problems
encountered when using pre-existing materials by preparing
the electrodes directly by chemical vapor deposition
(CVD) using metal precursors containing both carbon
and heteroatom sources, in addition to a carbon growth
catalyst to fabricate carbon nanotube electrodes with
incorporated electrocatalyst.
Benefits
Direct and low-cost methodology
No post-processing, post-treatment,
post-activation, or post-chemical modification
Heteroatom-doped carbon is inherently
catalytic
Features
Direct growth of aligned, high
surface area multi-walled carbon nanotubes on conductive
substrates
Simultaneous loading or dispersion
of electrocatalytic components via chemical vapor
deposition (CVD) of metal-containing or other heteroatom-containing
precursor(s)
Formation of mesoporous, high surface
area, 3-D electrode geometries of oriented carbon
nanotubes for increased mass transport
Demonstrated excellent electrocatalytic
ability for the reduction of dioxygen and the decomposition
of hydrogen peroxide
Carbon nanotube-based electrodes
and electrocatalyst are prepared simultaneously
Market Potential/Applications
U.S. battery market is estimated to
be at $10.4B (Freedonia, 2002). Carbon electrode demand
is expected to be 700kMT in 2003, growing to 725kMT
in 2004 (International Iron and Steel Institute SGL
Carbon Group, 2002). The market for carbon nanotube
materials was $8M in 2002 and is expected to reach over
$230M in the next few years (Business Communications
Corp., Chemical Engineering 2/2003). The fuel-cell market
expects to sell 3 million units in 2008, 50 million
units in 2010, and 200 million units in 2011 (Allied
Business Intelligence, IEEE Spectrum, 6/2003). The market
for fuel cells could reach $20B by 2010 (Principia Partners,
10/2002). The gas sensors market is expected to exceed
$2.5B by 2010 (Nanomaterials Research, LLC, 2002).
Applications:
Electroanalytical sensors, air batteries, fuel cells,
gas diffusion electrodes
IP Status
One PCT Application filed
UT Researcher
Keith Stevenson, Ph.D., Department
of Chemistry and Biochemistry, The University of Texas
at Austin
Stephen Maldonado, Department of Chemistry and Biochemistry,
The University of Texas at Austin
