Looking over the chemical literature with an RSS reader can really give you a sense of what the hot topics are, and what's cooling off. Remember when it seemed as if every third paper was about ionic liquids? You still see work in the area, but it's nowhere near as crazy as it was. (I had a colleague come by my office the other day and ask "Did anyone ever find out what to do with those things?") Similarly, gold catalysts have been all over the place in recent years, but seem, to my eye, to be calming down.
Some of these things are research areas that look promising, but die off when their limits become apparent. Some of them are almost sheer fads, with papers coming out from all sorts of odd places because the authors want to get in on the hot, publishable topics while they can. Others keep going because the topics themselves are important but ver hard to exhaust (metal-catalyzed couplings come to mind).
And there are areas that keep going in the literature because they look like they should be important and useful, and eventually will, but no one can quite get them to either work generally enough or get people to recognize that they do. The metal-catalyzed coupling literature was in this shape back in the 1970s and into the 1980s - there were a lot of disparate reactions that you could do with palladium, but none of them had exactly taken over the world. My vote for a current field in this protostar state is engineered solid-phase catalysis.
That may sound odd, since work on solid-phase catalysts has been going on for decades, and is of huge industrial importance. But many of the important catalysts have been arrived at either by luck or by an awful lot of hard slogging. The field is complicated enough - fiendishly so - that it's hard to draw general conclusions. If you have a good solution-phase catalyst, how do you make a solid-supported variety that works just as efficiently? Well. . .if you really want one, you make about a zillion variants and hope for the best, as far as I can see.
Part of the problem (as with the metal-catalyzed coupling world) is that there are just so many variables. The solid supports alone are enough to keep a person occupied for life, what with all the various aluminas, silicas, zeolites, polymers, mesoporous engineered thingies, and so on. Then you have the uncountable schemes for linking these surfaces to active catalysts - what functional groups to use, what density things should be on the surface, what distance you need between the surface and the catalyst, etc. And just linking up to the known catalysts is no light work, either, since most of these things were not made with convenient handles hanging off them.
As we get better at making (and characterizing) new kinds of surfaces and new kinds of macromolecular assemblies, we might start to get our hands around this subject. For now, though, it seems to be mostly in the descriptive stage: papers are of the "Hey, we made this thing and here's what it does" variety, with further work in the series being "Hey, remember that stuff we made? Turns out you can do this with it, too - who knew?" What you don't see, or not too darn often, is a paper describing the general principles of these processes. For the most part, we don't know them yet.
But if I had to pick an area that will eventually blossom into a host of applications, this would be high on the list. It's a mixture of surface chemistry, materials science, nanotechnology, and organic synthesis, and it's got a lot of promise. But then again, it's had a lot of promise for a long time now. . .
1. milkshake on December 14, 2010 11:04 AM writes...
I am not so sure about that. Maybe bi- and trimetallic catalysts have some potential - especially with zeolites providing acidic/Lewis acidic sites. But one cannot really engineer such catalysts at will, and the progress depends on serendipity.
Shibasaki came up with a fairly simple and somewhat tunable heterogennous catalyst concept based on bimetalic complexes of BINOL but they were not as catalytically active.
Attaching homogenous catalysts on a solid support: Lots of useful catalytic systems are using pre-catalysts that get activated in situ, and are quite air sensitive once activated...
Permalink to Comment2. silicon scientist on December 14, 2010 11:10 AM writes...
Interesting post! I'm actually considering getting into the heterogeneous catalysis field since semiconductor research seems to be on a steady decline. From what I've seen, there's a huge disconnect between the complex, granular materials that are of actual importance and the model systems that surface scientists can study and kind-of-sort-of understand...one crystallographic orientation at a time...using time-consuming and very expensive analytical tools.
But putting "engineered" in front of solid-state catalysis with the current state of our knowledge is akin to cavemen claiming they're combustion engineers after building a campfire.
Permalink to Comment3. startup on December 14, 2010 12:56 PM writes...
A few years ago Angewandte had a paper with fitting title: "Heterogeneous Catalysis — Still Magic or Already Science?"
Permalink to Comment4. anonymous on December 14, 2010 8:22 PM writes...
Every idea needs a "killer app". It's got to do something important and it's got to do it better then any competing method. Think CC bonds and Pd or spreadsheets and PC's.
Permalink to Comment5. Charles Pergiel on December 14, 2010 9:49 PM writes...
I've looked at a few academic papers (usually not chemistry) and I have been put off by the style: Lots of name dropping, lots of jargon, inscrutable formulas and little bits of english sprinkled hither and yon. Makes it exceedingly difficult to extract any useful information from them. I suppose for people who are thoroughly immersed in the subject they are easy enough to parse, but for anyone on the outside they are useless.
Guess I've just been looking for a place to vent.
Permalink to Comment6. Thomas Cotter on December 15, 2010 8:18 AM writes...
I am currently about to finish my doctorate in this field and I can say that there is a lot more science to it than magic, but having come from outside the discipline I can also appreciate the lack of apparent transparency which people perceive.
As a whole the het. cat. market grosses over 400bn per year, just in catalyst sales. When one considers the added value from the products produced in these processes it jumps to many trillions.
Being so broad a field with a long industrial heritage, coupled with the fact that surface science techniques to begin to understand these processes were only available in the latter half of the 20th century, means that you have a rather mongrel-like scientific pedigree with a bit of surface science, chem eng, solid state, theoretical/quantum chem and physical chemistry.
These all contribute to further understanding of process of which many were worked out empirically many years before. What has more recently been established is that you will reach a limit of understanding unless you are really able to observe such catalytic mechanisms in operating conditions which means 200-1000°C and 1-100 bar with any range of gaseous atm.
It is clear from the scale of industrial catalysis and potential scope of transformations (catalysts required for fuel cell electrodes, water-splitting, conversion of natural gas and many more) that heterogeneous catalysis is a central and requisite aspect of futurising our society and reducing the toll of humanity on the planet's resources.
@Charles P.
I would suggest that instead of looking for a place to vent, look for a place to start. There are a vast number of publications in the area and certainly if you don't know what you are looking for then it will be impenetrable (as in general most inorg. chemists find org. journals to be).
There are also solutions for het. cat. in organic reactions but homogeneous catalysis will likely be a useful tool for some time. That said, a methanol synthesis catalyst generally lasts for 2-3 years and producing thousands of times it's weight in product, all ready to be easily recycled after use - certainly there exists a disparity with regards to economy of scale.
@silicon scientist
Permalink to Commentthere is a huge disconnect between the models and reality, but surely that is the fun in it! In that way it shares a lot in common with semiconductor research except that we are trying to extend the spectrum of techniques and understanding towards inherently complex materials
7. sepisp on December 16, 2010 4:23 AM writes...
Fortunately heterogeneous catalysis is a real field of science and not a fad. That is because when the interest dies off, funding is not going to disappear. Namely, there's a lot of oil money poured into this research, for obvious reasons: oil refineries are the main "customers" of the catalysis scientist.
Permalink to Comment8. Carmen Crocco on October 8, 2011 5:49 AM writes...
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