Neodymium Nickelate High Temperature Electrolysis of Water In Solid Oxide Cells.

-NNadir




(Cross posted at
Daily Kos, as a diary with poll. It is appropriate here since it discusses some aspects of the fission product neodymium and also refers to means for making chemical fuels from nuclear energy.)

As we all know, the hydrogen HYPErcar has been in showrooms since 2005...

Um...

No? It isn't? You're kidding?!?

Well, it could have happened...

If it had happened we would have needed, um, hydrogen. Actually hydrogen is not a particularly useful consumer fuel. Its critical temperature is actually lower than the boiling point of liquid nitrogen, meaning that it requires huge amounts of energy to liquify it and, in fact, pretty large amounts of energy to obtain it.

Something called the "second law of thermodynamics," - a law that various legislatures have attempted to repeal and which often the subject of "efficiency will save us" arguments that are meaningless in places, like, say, Gabon - means that energy will always be lost whenever hydrogen is obtained from water or any other hydrogen containing fuel, methane for instance.

(Interestingly, the critical temperature of methane is considerably higher than that of hydrogen.)

People of course are always claiming that hydrogen can be made from so called renewable energy. For instance, for some years, Norway - in an attempt to put lipstick on its offshore oil and gas pig - funded a "wind to hydrogen" scam on the island of Utsira that powered ten homes.

Ten.

Not ten thousand.

Not ten million.

Ten.

We're saved, all ten of us living on this planet.

Predictably, it was funded by Stadtoil, Norway's offshore oil and gas company, again, to divert attention from the oil and gas pig that provides most of that august nation's wealth. At the very same time as Norway was running this little red herring "wind to hydrogen" scam, it was building its first dangerous natural gas power plant at Kårstø: Previously all Norwegian electricity was produced by hydroelectric facilities, but every damn river in the country was saturated with dams.

Predictably, Stadtoil handed out a bunch of bull about how it was going to build a sequestration facility for the dangerous natural gas waste in the Sleipner oil fields. As soon as the plant was finished that scam was shitcanned as "too expensive." I don't believe they were ever serious about this, any more than Amory Lovins is remotely interested in opposing the oil companies that fund his little "consulting" firm in Snowmass, far above the oil soaked fishing towns of Louisiana.

What a surprise.

The claim is now made that the plant is cleaner than other gas plants, which is, to my mind at least, rather like announcing that it is better to have breast cancer than it is to have melanoma, since the latter cancer kills faster than the former.

Heckuva job.

Anyway. The title of this diary is about Neodymium Nickelate.

Neodymium is an interesting metal. It is one of the metals we now refer to has a "lanthanide" - the historic name for this class of "f orbital" metals was "rare earth." Although the metal had been discovered spectroscopically in the 19th century, it was not actually isolated until the 1920's, and was not commercially available in pure form until the 1950's, when ion exchange and solvent extraction methods were developed.

It is often said that the "rare earth" name was a misnomer, but it should not be claimed either that it is common. Most of the neodymium in the world is mined in China, although historically the element was obtained in mines in the United States that were not economic in former times. Rising neodymium prices may change that and some closed mines may reopen. China recently announced restrictions on export of the metal.

World production of neodymium is on the order of 10,000 tons a year. The chief use of the metal is to make particularly strong permanent magnets which are alloys of iron, neodymium, and boron. The strength of these magnets means that they can be relatively lightweight, and thus they are commonly used in wind turbines of the type that bankers hype so that governments will subsidize, um, bankers who hype wind plants.

Governments can never subsidize the banking industry enough.

Some day there may be neodymium shortages in the future. I can't say. Although I am no fan of the wind industry, it has managed to sell itself - much to the detriment of the future - well enough that lots of money will be thrown down that particular rabbit hole, just like lots of money was thrown down the solar rabbit hole with very little result, so little as to approach zero.

Wind turbines have a nasty habit of falling over:








One hopes that the neodymium is recovered from the wrecks to make new wind turbines to fall over.

Natural neodymium, by the way, contains two radioactive isotopes, Nd-144, and Nd-150. However the half-lives of these two isotopes are much, much, much, much longer than the age of the universe, and thus essentially all of Nd-144 and Nd-150 that has ever existed, still exists. The radioactivity is so low, that only very, very, very, very sensitive detectors have been able to detect it at all, and it is nearly certain that the only reason people even looked to see if neodymium is radioactive had to do with theoretical aspects relating to nuclear science and the "thermodynamics" of nuclei.

It is possible to make pure neodymium-144 from used nuclear fuel. About 5% of fissions in U-235 based nuclear fuel have the mass number 144. Very often this is initially present as radioactive cerium-144. This isotope decays through two beta decays - with a half-life of about 284 days - to give neodymium-144. Thus if one isolates radioactive cerium from a nuclear reactor, and waits a few years, one can isolate Nd-144.

Neodymium is what I like to call a "node element" in nuclear fuel. With the exception of the above mentioned isotopes - which are effectively stable nuclei - no neodymium isotopes are very long lived, and thus it is possible to isolate essentially non-radioactive neodymium from used nuclear fuel and use it in any way one chooses, even for silly wind turbines.

Somewhere close to 10% of nuclear fissions will produce an isotope that will ultimately decay to a neodymium isotope.

The amount of neodymium that is likely to be found in used nuclear fuel in the United States is probably a drop in the bucket however, on the order of between 300 and 400 metric tons.

China has announced plans to build 200 nuclear reactors by 2030 - over the next 20 years - and 400 to 500 by 2050. Twenty-four are now under construction. Thus China will probably have some excess neodymium from these activities, not that they actually need it.

In any case, there are zero dedicated industrial scale "wind to hydrogen" plants on the drawing board anywhere on this planet, zero in existence, and zero hydrogen HYPErcars that are fueled by exclusively by wind (or solar) power on the planet.

There are however, some electrolysis plants on the planet that make hydrogen as a side product in the chlorine industry. About one to two percent of world industrial hydrogen production is made this way, the other 98% of the world's hydrogen is made by partial oxidation of dangerous natural gas, after which the dangerous natural gas waste is dumped in the favorite dump of the gas industry, earth's atmosphere. (A side product of the manufacture of chlorine via electrolysis is caustic soda, a very important industrial chemical.)

The problem with electrolysis as a means to hydrogen production is efficiency: As noted above, the second law of thermodynamics requires that all conversions of one form of energy to another, say electricity to chemical, will waste some energy. If the electricity is itself made from chemical energy - say a dangerous natural gas power plant like the plant at Kårstø - even more energy will be wasted.

One way to increase the efficiency of electrolysis is to conduct the electrolysis at very high temperatures, say the temperatures of supercritical water: Water under pressure at a temperature above 373C that is neither a gas nor a liquid but has properties of both. However supercritical water is corrosive, and special materials are needed to handle it: It's "neutral pH" is actually quite acidic, comparable, roughly, to 3N hydrochloric acid. Coupling this property with the property that anodes - the electrode where oxygen is made in the splitting of water also are subject to corrosion. Normally liquid mercury electrodes are used, and this results in some toxicological issues. (Most chlorine bleach contains a small amount of mercury.)

A recent publication in the scientific literature describes a new material that may work to solve the problems associated with high temperature electrolysis. The paper is Journal of Power Sources 195 (2010) 744–749. I cannot provide a link to it since the Elsevier "Science Direct" website has been down all day for maintainance.

Here's some excerpts of the paper:

For economical and ecological reasons, hydrogen is considered as a major energetic vector for the future. In order to gain the status of leading alternative fuel, one major question which still remains to be solved, is the massive production using clean processes with low or no CO2 emissions. High temperature steam electrolysis (HTSE) is one of the most promising processes to achieve this target, water molecule being split into hydrogen and oxygen using electricity and heat which can be provided by nuclear power plants for example [1]. However, in order to produce by HTSE the amount of hydrogen needed to replace even partially the fossil fuels, many dedicated power plants would be necessary. Thus, the development of highly efficient systems is required. Each component of the system has to be optimized, from the balance of plant to the solid oxide electrolysis cell (SOEC) where the HTSE reaction occurs. Most of current studies reported on HTSE consider reversible solid oxide cells (fuel cell/electrolysis cell) [2–5], containing hydrogen electrode made of cermet, zirconia based electrolyte,and perovskite-type oxygen electrode. An alternative oxygen electrode material, whose composition is Nd2NiO4+δ is presented in this work...

...

Here's the process by which the electrode was made:

The Nd2NiO4+δ powder was prepared by the nitrate–citrate route as described by Courty et al. [11]. Stoichiometric amounts of neodymium and nickel oxides were dissolved in diluted nitric acid. After addition of a large excess of citric acid for chelating the cations, the solution was dehydrated and heated until self-combustion of the precipitate to obtain submicronic precursor particles [9]. The final annealing was performed at 1000 ◦C for 12 h to obtain a single phase. The powder was then ball milled to obtain an median grain size (d0.5) of about 0.8 m. A terpineol-based slurry was prepared with this powder, and then deposited on the electrolyte by screen printing before a sintering step at 1100 ◦C for 3 h in air [12]. The thickness of the final Nd2NiO4+δ porous layer was about 30 μm (Fig. 1). A gold annular reference electrode (2mm wide) was painted on the oxygen electrode side of the electrolyte and then annealed at 750 ◦C for 30 min in air (Fig. 2). The distance between working and reference electrodes (more than 100 times the thickness of the electrolyte) was set to avoid as much as possible measurement artifacts due to the influence of the current lines through the electrolyte on the reference electrode [13]. The studied cell was placed in a ceramic housing and sealed using glass paste and gold rings, the whole being inside a specific setup equipped with a so called 3rd chamber with controlled atmosphere for the reference electrode (Fig. 2). The pressure in each chamber was 1 atm.

The electrodes are operated at very high temperatures and the NdNiO4+δ hyper stoichiometric oxygen electrode performs quite well.

The NdNiO4+δ at 850C gave the best result, a 53% conversion of steam to hydrogen.

Interesting, I think. Nonstoichiometric oxygen compounds have many interesting properties, in particular the perovskites, and many uses are expected for them.

As for hydrogen, it's a useful intermediate for better fuels like dimethyl ether, DME, but is pretty much useless as a consumer item, if you want my opinion (but maybe you don't). But that's another story.