Is science sometimes in danger of getting tunnel vision? Recently published ebook author, Ian Miller, looks at other possible theories arising from data that we think we understand. Can looking problems in a different light give scientists a different perspective?

Scientific Papers, Funding, Commercial Applicability And Relevance: Scientists Have Mixed Objectives.

There are a number of problems that seem to be looming, one of which is the climatic effects of the so-called greenhouse gases. Science should be able to address such problems, but the question arises when a discovery is made is, is this a solution to the designated problem, could it be a solution to the designated problem if some further problems can be overcome, or is it simply an interesting observation but essentially irrelevant in terms of solving any of our problems? With the problem of getting funding for science, "relevance" often becomes an issue. Accordingly, funding applications frequently make significant claims as to what their research might achieve, and there are advantages in carrying this over into the subsequent papers. Of course some of these papers may truly herald an opportunity. So, what do you make of the following?
 
Ammonia is an important chemical for fertilizer, and is usually made through the Haber-Bosch process, which involves reacting nitrogen gas with hydrogen under pressure, the hydrogen being made by steam reforming of methane, in turn obtained from natural gas. The oxygen from the steam ends up eventually as carbon dioxide, so it contributes to the greenhouse effect. However, a new process has been claimed (Science, 345: 638 – 640) that involves electrolysis of air and steam in a pressurized molten hydroxide suspension of nano-sized Fe2O3, at temperatures of 200 – 250 oC. This process results in the conversion of nitrogen to ammonia with an efficiency that is apparently 35% of the applied current, the other 65% resulting in excess hydrogen. Hydrogen would remain a marketable product. The chemistry is interesting. Iron/iron oxide is a catalyst for the Haber-Bosch process, but that process uses pressures considerably higher than would be found in this reaction. That comparison is probably irrelevant, as is shown by ball-milling standard iron oxide, in which case the reaction did not go, so the nano-sizing is important. The question then is, is this a solution to a problem or merely an interesting side-issue? That leaves open the question, how likely is it that this reaction will scale up successfully, and if it does, then run successfully?
 
The first problem that I could see is that the efficiency drops off at higher current, thus the efficiency of one synthesis was >30% at 20 mA, but ~7% at 250 mA. The suggestion was that the conversion is limited by the available area of nano-Fe2O3, which may or may not be fixable during scale-up. From the chemical point of view, the nanoparticles were dispersed throughout the solution, but the electron transfer would presumably occur at the electrodes, so that raises the question, exactly what are the nanoparticles doing? The electrodes were nickel, so they should not be a problem for scale-up, but the area might be. The production rates were in the order of 7 x 10-9 mol NH3 per second per square centimetre. That would require a very large area to get 1t/hr, which is hardly a rate to get excited about. The requirement for nano-sized  Fe2O3 would also worry me because Fe2O3 slowly dissolves in hot sodium hydroxide solution to make sodium ferrite. This was not mentioned in the article. On the other hand, they found conditions that stabilized production for six hours. (Actually, it may not be beyond the bounds of possibility that sodium ferrite is the catalyst, as nano-sized Fe2O3 might well be more reactive than the bulk oxide. That is yet another aspect that at least needs answering.) Is this possibly a commercial process? My guess is no, at this stage at least, but it does provide an interesting new opportunity for research. If they could get the current density up significantly, then perhaps there is something here.
 
Would that help solve the greenhouse problem? In my view, since this electricity would be the marginal production, no, unless we find a way to make electricity that totally stops the use of fossil fuels to make electricity. Nevertheless, the production of ammonia is required to address the food problem. However, if we really want to do something about global warming through ammonia usage, then a good place to start would be to make nitrogen fertilizers more efficient. A very large amount of such nitrogen finds its way into N2O, presumably through the decomposition of ammonium nitrite.  Accordingly, there is plenty of work remaining for further research. The question then is, how to fund it? Unfortunately, the scientist's first duty is to obtain funding, which encourages flag waving in papers.
Posted by Ian Miller on Sep 29, 2014 3:17 AM Europe/London

Share this |

Share to Facebook Share to Twitter Share to Linked More...

Leave a comment?

You must be signed in to leave a comment on MyRSC blogs.

Register free for an account at http://my.rsc.org/registration.