The 2007 Nobel Prize in Chemistry

The winner of the 2007 Nobel Prize for Chemistry is Gerhard Ertl, now emeritus professor at Berlin's Fritz Haber Institute of the Max Planck Society, for his groundbreaking studies in surface chemistry. 

What is surface chemistry? 

Surface chemistry is the study of how molecules and atoms behave at surfaces: for example, working out what happens when gas molecules smack into the tightly-held atoms in the surface of a solid. 

Why is surface chemistry important? 

Surfaces are central to many important chemical reactions:

• The ozone layer breaks down when gases react on the surfaces of ice crystals in the stratosphere.
• Metal surfaces in cars' catalytic converters clean up toxic carbon monoxide before it escapes from the exhaust. 
• Iron rusts when oxygen molecules attach to its surface. 
• Artificial fertilisers contain ammonia, which is made when nitrogen and hydrogen gas react on an iron surface. 
• Many medicinal drugs and materials for the electronics industry are made using reactions aided by reactive surfaces.    

In all these reactions, chemicals would combine much more slowly, or not at all, if they weren't interacting with some kind of surface. By understanding these processes, chemists can design better surfaces to improve chemical reactions and create new materials, fuels, and pharmaceuticals. 

Why do surfaces speed up chemical reactions? 

Surfaces that speed up chemical reactions are called catalysts. They do this by changing the behaviour of molecules attached to them. For example, take the industrial reaction which helps produce over 100 million tonnes of fertiliser a year - the Haber-Bosch process, which makes ammonia from nitrogen and hydrogen. If those two gases are mixed together, nothing happens. But add an iron catalyst and the gases react more easily. The nitrogen molecule binds to the surface of iron and falls apart, recombining with nearby hydrogen atoms to make a new molecule, ammonia, which falls off the iron again. 

What did Ertl do to win his Nobel Prize? 

Ertl helped transform surface chemistry into its modern form, showing that you could work out how molecules were moving, step by step, on the surface of a solid. Before the 1960s, it was impossible to form a picture of exactly what molecules were doing at surfaces, though they were already used industrially to speed up many reactions. 

Over a lifetime, Ertl helped explain the mystery behind this black box. He prepared clean metal surfaces in almost perfect vacuum and slowly injected gas molecules onto them. Though the molecules couldn't be seen, it was possible to work out their behaviour by firing electrons, x-rays, and ultraviolet and infrared rays at them. The rays would bounce off, diffract, or knock out electrons - taken together, this evidence allowed Ertl to explain what was going on when nitrogen and hydrogen reacted on iron, or when carbon monoxide turns into carbon dioxide on the surface of platinum, for example. He picked his way through a formidable series of methods to a comprehensive understanding; showing how molecules organised themselves and moved around on different areas of the surface in complicated rhythms and patterns. And in turn, chemists now understand how to choose and change surface composition and shape to speed up thousands of chemical reactions. 

Why was Ertl special? 

Many other chemists in the 1970s, 80s, and 90s contributed to the modern emergence of surface chemistry. Ertl stands out not because of one discovery, but because his style of investigation set a benchmark for all other studies into molecular behaviour at surfaces. Ertl was never satisfied with one interesting observation: he had a knack of picking the most suitable methods from the toolbox to elegantly answer questions which a few decades before seemed impossible to answer. 

Richard Van Noorden, Chemistry World magazine

Professor Ertl has a long history of involvement with the RSC, both as a published author and advisor. 

He has served on both the Faraday Transactions Editorial and Physical Chemistry Chemical Physics (PCCP) Advisory Boards and been a regular contributor to our international conference series, the Faraday Discussions. This included delivering the Spiers Memorial Lecture at Faraday Discussion 121 in 2002 when he was the RSC Spiers lecture and prize winner. 

Professor Ertl is also the current winner of the Faraday lectureship, the RSC Faraday Division's oldest award. 

Professor David Clary, President of the RSC Faraday Division, welcomed the Nobel announcement, "The Faraday Division of the Royal Society of Chemistry is delighted that Professor Gerhard Ertl has been awarded the 2007 Nobel Prize for Chemistry. Professor Ertl's pioneering research on surface chemistry has been an inspiration for many physical chemists in the United Kingdom."