On Jul 31, 2008, at 12:06 PM, Jones Beene wrote:
...they do
not even understand the difference between Redox
half-cell reactions, and why two half-cells do not
imply a workable whole-cell - not to mention: what
really constitutes a breakthrough.
... we already possess an efficient way to get oxygen,
and you're breathing with it now. What about the
hydrogen, Luis?
Let me answer that. This is NO breakthrough, ...
Is MIT really this hard-up for a news story, or what
am I missing?
Jones
Consider the following.
From:
http://tinyurl.com/5hw4jd
page 2: "Nocera's catalyst is made from cobalt, phosphate and an
electrode that produces oxygen from water by using 90 percent less
electricity than current methods, which use the costly metal platinum."
The above statement must mean the anode interface potential drop has
been reduced by 90 percent. I say this in part because the photos of
the experiment show a typical three electrode scheme for measuring
half cell potentials. Dropping one of the half-cell potentials by 90
percent is a HUGE advancement. This is drop in the anode interface
potential, which is about half the cell minimum potential drop,
therefore represents roughly a 45 percent overall improvement over
other technologies, assuming the plate gap is maintained sufficiently
small and the gas bubbles are sufficiently handled, in a manner
similar or better than typical commercial electrolysers. In fact, if
this potential drop assumption is true, it changes the baseline for
the method of even measuring electrolytic voltage efficiency. The
1.24 V baseline is moved down to about 0.7 V. Typical commercial
electrolysers run (or at least used to run) at about 1.9 V, or 65%
voltage efficiency. The 0.6 V drop for the anode would drop the
overall required voltage to 1.3 V for similar hydrogen production,
and thus, by the old measuring standard, would cause the cell to
operate at nearly 100% voltage efficiency.
Further, the anode no longer needs to be made of platinum in order to
avoid anode digestion because it is continually recoated (with
phosphorous I assume) by the electrolysis process. Electrolyser
cathodes are already made fairly efficiently using thin platinum
coatings, though stainless steel works pretty well too.
This eventually will present a major threat to various battery
companies that are in or moving into the renewable energy
transmission power management field. It also represents a huge
opportunity for developing solar powered fertilizer production,
especially in sunny desert regions. This can free up natural gas for
other uses, like vehicle propulsion.
Lastly, the cell components are not highly corrosive, expensive, or
even resource limited, so this permits wide use of the technology in
small distributed systems and in third world countries. The timeline
for this is greatly reduced by similar recent advancements in fuel
cells.
It appears to me this is a world changing development. I expect it
will not take 10 years to see it applied to utilities power
management. I don't see why it wold not be possible to just change
out the electrolyte in order to significantly benefit some
electrolysers. If true, then it is only intellectual property rights
that might get in the way of progress, and that is explicitly to be
avoided according to statements by MIT.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
