Congratulations to Professor Ertl on his Nobel Prize.
Ertl’s work is important because chemical reactions play by different rules when one or more of the molecules is tied to a surface and can’t flop around in solution. All kinds of everyday processes occur only at surfaces – the rusting of iron or the adhering of paint to a wall. it’s really difficult to took at a process that occurs on a layer of matter that is only a few atoms wide. Ertl is a master of adapting whatever techniques get him the answer he needs, and that has made him an analytical jack-of-all trades.
Ertl’s work has had probably the most direct impact on the science of catalysts. Catalysis is almost exclusively a surface phenomenon, and much of the materials we use and the clean air we breathe is owed to the catylitic reactions that Ertl studied. Mankind has long known that certain substances catalyze reactions, but Ertl began to show us how and why. The importance of that can not be overstated. It is exactly analgous to that period in the dye industry’s history when Perkin’s rivals in Germany began to understand the whys and hows of organic synthesis – in Derek Lowe’s words, leaving the era of witchcraft. The German dyers then began to best Perkin’s trial-and error method – accelerating progress and beating the master at his own game:
It was not long after Perkin’s original feat that Kekule and his structural formulas supplied organic chemists with a map of the territory, so to speak. Using that map, they could work out logical schemes of reactions, reasonable methods for altering a structural formula bit by bit in order to convert one molecule into another. It became possible to synthesize new organic chemicals not by accident, as in Perkin’s triumph, but with deliberation.
We are about to watch this same process happen in the development of indutrial catalysts.
Another surface reaction of interest, due to its political ramifications, is the effect of solid surfaces on the catalytic destruction of ozone by halides.
It turns out that the reaction rates of halides with ozone vary tremendously depending on whether a solid surface exit which will hold the halide in place. Any surface will do from a tiny ice crystal to the walls of a reaction vessel in a lab. Turns out that the estimations of the ozone destroying power of halides based on the rate observed in vessels in the lab overstated the rate that would occur in the upper atmosphere with few solid surfaces. Indeed, it appears that the availability of surfaces due to ice formation or volcanos has a larger impact on ozone destruction that the levels of halides.
Shannon, Ertl’s work touched on that, too. He talked about that when I met him at a lecture in the early 90s.
Shannon,
With respect to stratosphere ozone concentrations, it has long been known that 1) air temps cold enough to form polar stratospheric clouds has a large impact upon ozone loss rates and 2) there are active volcanoes in Antarctica, which emit halides, sulfates, silicates, etc into the stratosphere. The greater the extent of polar stratospheric clouds, the greater the ozone loss ceteris paribus. The greater the local emission of volcanic gas and dust, the greater the ozone loss, ceteris paribus.
Ever since IGY 1957, it has been known that the Antarctic stratosphere temperatures are more often lower than those of the Arctic stratosphere; and that polar stratospheric clouds are rare in the Arctic relative to the Antarctic.