The door to the hydrogen economy may be made of cobalt

 

The door to the hydrogen economy may be made of cobalt
    For years people have talked of fuel cells as as a salvation from
our current oil-based economy to a new, enlightened hydrogen-based
economy where pollution from energy will be a thing of the past.  While
this, like many visions of the future, is a bit grandiose, it is based
in fact.  Fuel cells are operate on the same principle as all modern
engines: they seek to turn potential chemical energy stored in a fuel
into useful mechanical energy.  The big difference from the engines of
today is that the main source of fuel for a fuel cell is hydrogen, and
its by-product is merely fresh water.  One promising class of fuel
cells are polymer electrolyte fuel cells, an example of a proton
exchange fuel cell.  While these are not a new technology-they were
first used on the Apollo missions in the 1960s and 1970s-they have
one prohibitive barrier: cost.

    Current PEFC consist of a polymer membrane sandwiched between an
anode and a cathode, which are then connected to form an electrical
current.  The basic chemistry of a fuel cell is that molecular hydrogen
(H2) is present on the anode side where it is oxidized into two protons
(H+) and two electrons (e-).  The electrons flow to the cathode
creating an electrical current that can be used to power devices.  The
free protons migrate across the polyelectrolyte membrane to participate
in an oxygen reduction reaction at the cathode.  Here on the cathode
side, pure oxygen (O2) or air is present and it combines with the
electrons that have flowed across the circuit, and along with the
protons that have migrated across the membrane react to form pure water
(H2O).  While this is very simple in theory, performing the oxidation
and reduction reactions is not easy, therefore catalysts are used to
facilitate these reactions.  Currently precious metal catalysts are
used to aid these reactions.  These catalysts are primarily platinum
(Pt) and to a lesser extent palladium (Pd) and ruthenium (Ru).  Use of
these metals presents a few problems; as mentioned above they are
expensive (Pt is currently selling for $45/gm), these metals are rare
(Pt occurs at only 37 parts per billion in the Earth's crust), and
their catalytic activity can significantly degrade over time.

    Recent work by scientists at Los Alamos National Laboratory may
alleviate some of these issues.  The researchers have found a class of
non-precious metal composites that can replace the platinum on the
cathode side of a PEFC.  While it would be ideal to be able to replace
the platinum on both electrodes on the cell, replacing it on the
cathode only will result in a large decrease in the amount of catalyst
needed. This is due to the fact that the slower oxygen reduction
reaction requires much more catalyst than the hydrogen oxidation
reaction that takes place at the anode.  The researchers found that a
composite consisting of cobalt (Co, a non-precious metal) covalently
trapped in-between polypyrolle (PPY, [C4NH3]n) backbones on an
amorphous carbon support could give both decent fuel cell performance,
and excellent stability, all at a low cost.  Fuel cells built with this
catalyst were tested in a pure H2 and O2 environment and were reported
to be capable of generating ~0.2 A/cm2 at 0.5V potential.  While this
is less that what may be obtained with a Pt-based catalyst system (~ 1
A/cm2, from early reported numbers), it was shown to be able to
maintain this output level for the entirety of a 100 hour test.  While
it may not produce the same amount of energy per unit time, this
technology has shown that it can produce energy at a fraction of the
cost-cobalt costs ~$0.20/gm.  It can also sustain its energy output
for long periods of time, longer than the traditional precious metal
catalyst are capable.  This work represents a large step towards
economically viable hydrogen fuel cells, something many the world have
been waiting for.
http://arstechnica.com/journals/science.ars/2006/9/8/5232

 



But where does the hydrogen come from?

Nick

 



nicksanspam@ece.villanova.edu wrote:


It's *magic* ! It just 'happens'.

Graham

 

On 2006-09-08 17:38:44 -0700, nicksanspam@ece.villanova.edu said:


That is the pink elephant in the back of the room that people in the
people spending the grant money don't want to talk about. : )
--
Mike
Some say we must tax corporations more.  What they do not understand is
that corporations do not pay taxes.  One of our governments conditions
for a companies existence is they collect the taxes from their
customers and pass them to the government.
    Mike Swift

 

On alt.energy.homepower, in

Correction: A dishonest coward who _sometimes_ calls himself "lkgeo1" wrote:

<article not downloaded:
http://slrn.sourceforge.net/docs/README.offline>


Let's see. How is hydrogen manufactured? By running very large
electrical currents through fresh water (salt water won't work)
or by running superheated steam over red-hot coke (charcoal made
from coal).

And that water has to be purified first.

Guess what many top geopolitical analysts think is going to be
the cause of the next major wars: Freshwater shortages.

And those projections don't take into account taking truly
enormous amounts of fresh water and and turning it into hydrogen.

And how must it be stored and transported? As a liquid, which
requires further enormous inputs of energy.

This is another one of the pipe dream, anti-solutions of the
uneducated psuedo-environmentalists.

---------------------------------------------------------------

But what does this guy care if he makes a fool of himself? He'll
just drop this alias and go hide behind another one.

That's why I don't even bother reading the articles of trolls.

Alan

--
If you replied to an article of mine and are wondering
why I didn't respond to you, the fact is that I didn't
even download your article. For an explanation, see:
http://home.earthlink.net/~alanconnor/newsfilter.html