Chemist's Ultimate Birthday Gift: A Nobel

What do you give the chemist who has everything for his birthday? How about the Nobel Prize?

Gerhard Ertl of Germany won the 2007 Nobel Prize in chemistry on Wednesday - his 71st birthday - for studies of chemical reactions on solid surfaces, which are key to understanding questions like why the ozone layer is thinning.

Ertl's research laid the foundation of modern surface chemistry, which has helped explain how fuel cells work, how catalytic converters clean up car exhausts and even why iron rusts, the Royal Swedish Academy of Sciences said.

Ertl told reporters in a live teleconference that it "is the best birthday present that you can give to somebody."

Ertl - the first German to win the chemistry prize since 1988 - showed how reliable results could be obtained in a difficult area of research, and his findings applied in both academic studies and industrial development, the academy said.

"Gerhard Ertl has succeeded in providing a detailed description of how chemical reactions take place on surfaces and has in this way laid the foundation of modern surface chemistry," the award citation said.

The academy highlighted Ertl's studies of a chemical process in which nitrogen is extracted from the air, using iron as a catalyst, for inclusion in artificial fertilizers. That process has had "enormous economic significance," the academy said.

Ertl has also studied the oxidation for carbon monoxide on platinum, a reaction that helps clean exhaust emissions in the catalytic converters of cars. Automakers worldwide have in recent years been trying to produce cars that are more fuel-efficient and less harmful to the environment.

Other scientists have been able to build on his research and methodology to further understanding of surface chemistry, which is a key field of research for the chemical industry.

"Surface chemistry can even explain the destruction of the ozone layer as vital steps in the reaction actually take place on the surfaces of small crystals of ice in the stratosphere," the award citation said.

Ertl is a professor emeritus at the Max Planck Institute, one of Germany's most prominent research centers. He said he was aware that he could be considered a candidate, but he was without words after he found out that he had won the Nobel Prize.

"I was really speechless," . "Of course, one knows that one is one of the candidates, but there are always at least a dozen candidates, so I was really speechless."

Nevertheless, he noted that he had a full 20 minutes before the phones started ringing off the hook with journalists seeking to contact him.

In that time, he gathered with all of his colleagues at the Fritz Haber Institute in Berlin, part of Germany's Max Planck Institute, to toast the prize.

Johann Deisenhofer, Robert Huber and Hartmut Michel were the last German scientists to win the Nobel Prize in chemistry when they shared the award in 1988.

The chemistry award was the third of this year's Nobel Prizes to be announced.

Americans Mario R. Capecchi and Oliver Smithies, and Briton Sir Martin J. Evans, won the 2007 Nobel Prize in medicine on Monday for groundbreaking discoveries that led to a powerful technique for manipulating mouse genes.

On Tuesday, France's Albert Fert and German Peter Gruenberg won the physics award for discovering a phenomenon that lets computers and digital music players store reams of data on ever-shrinking hard disks.

Prizes for literature, peace and economics will be announced through Oct. 15.

The awards - each worth 10 million Swedish kronor ($1.5 million) - will be handed out by Sweden's King Carl XVI Gustaf at a ceremony in Stockholm on Dec. 10.