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Charlie:

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Great update and analysis (and the more detailed article on the wiki is an excellent way to stimulate conversation)!  Besides the catalyst species (Fe3O4 is a good one to start with) and surface structure (clean) the number one factor to consider is probably the specific surface area, in units of meters squared per gram (m2/g).  As an example, a 1 cm diameter sphere of magnetite (5.2 g/cm3, or 5.2x106 g/m3) has a surface area (always 3 divided by the product of the radius times the density, in consistent units) of .00012 m2/g and for a sphere of iron or stainless with a surface layer of rust it is even smaller.

Wikipedia says activated carbon is 3000 m2/gram and typical catalysts have on the order of several hundred m2/g so we see we have a very long way to go if we want to get a high surface area - we'll assume that the reaction progress goes up linearly with the surface area held within the reactor - by crushing up solid things we find in ordinary life, like ore or stuff around the shop.  To get a paltry 1 m2/g requires us to grind to effective spheres of just over 1 micrometer - pretty fine stuff!  This is just a reality check, and it indicates why supported catalysts (the metal or oxide deposited on just the very surface of some very high surface area material like specially prepared alumina) are so popular, and not just for very expensive catalysts like those used in automobile catalytic converters.  Jay has been looking into making our own supported catalyst - you can buy the support from Sigma Aldrich or similar chemical supply companies, then deposit the monolayer or so thickness of metal oxide on them by some only somewhat fancy chemistry steps.

Unfortunately, surface area is typically only measured in well equipped laboratories, often using the BET method (the T is for Edward Teller, before his bomb days), but where there is a DIY will there is a DIY way.  Until then, grinding stuff really fine, or finding better ways to increase the surface area, is the best path - there will always be a syngas reaction, we just have to be prepared to measure very tiny amounts of reaction products (diluted by large volumes of syngas) if the specific surface area is relatively low.

[JayAlchemAPL]

Charlie,
Thanks for the reply,

Yes I have been experimenting with depositing catalysts on alumina supports. This co-precipitation method is not only attractive for its high surface area and a lower volume of actual catalyst needed, but for weight. Some supports are also being considered over others due to their qualities as "promoters" as well.

Turns out that when the column is packed with the iron catalyst it is pretty heavy. Turns out this is much of an issue for larger plants due to the cost and design of the foundation of the building structure.



The decrease in weight of the over all design is not as big of a gain as the catalytic efficiency, and for this reason the supported catalysts are a much greater win. I started out with an alumina oxide support to give the co-precipitation method a try. Turns out it is very simple.

Alumina oxide supports are also sold as 'bumping' or 'boiling stones'. These small inert stones are used to offer a molecular rough surface for the nucleation of gas bubbles. When boiling in a molecular smooth surface, liquids can become super heated just on the fact that there is no spot for a gas bubble to start forming. The liquid will bump, causing a splash when all of a sudden nucleation happens and a huge bubble is formed at random and a more frantic boiling occurs sporadically.

These can be purchased easily in 50lb bags. I was able to find them easily, I can't recall how much they are but  I ended up purchasing a smaller amount at first.

Below is a picture of the alumina oxide support before and after co-precipitation:



This procedure starts with obtaining ferric nitrate as the iron carrier. Co-precipitation usual refers to having a second precipitate typically of cobalt, in the form of cobaltous nitrate. In this case, I followed a procedure that incorporates cupric nitrate as the co-precipitate.



In some suggestions the iron oxide catalyst is mixed in the range of 5% or so of cobalt oxide or copper oxide by weight. The respective metal nitrates are dissolved in an aqueous solution. In this case I made a 2 molar solution and added 3 grams of alumina oxide stones to the solution. Next, the solution is neutralized by adding a baking soda and water slowly. I added about a table spoon of baking soda to about 50 ml of water at first and slowly mixed it in the metal nitrate solution. The solution started to change color to a muddy red and it became obvious that Fe2O3 was depositing onto the alumina stone surface.
There is some experimentation among the literature to compare varied concentrations of the metal carriers as well as the neutralizing agent to better hone in on the concentrations that give higher yields to more efficient catalysts. There is also some discussion in this niche that residual potassium salt shows a higher catalytic promoting qualities of the over all catalyst, so the suggestion of using potassium bicarbonate in contrast with sodium bicarbonate is being explored as the neutralizing agent.  I have referred to this paper for the above experiment: http://wiki.gekgasif...h Catalysts.pdf