Issue Date: April 7, 2008
Surface Science's Sage
AS GIANTS GO, Gabor A. Somorjai isn't very tall. At 5 feet 8 inches he hardly towers over his fellow scientists at the University of California, Berkeley, or at Lawrence Berkeley National Laboratory, where for more than 40 years he has served as a chemistry professor and staff scientist. Yet even though the 72-year-old Somorjai isn't literally an unusually big man, he stands head and shoulders above other leading scientists for his pioneering role in and ongoing contributions to surface chemistry, a field of far-reaching and still-growing scientific and technological significance.
One way to gauge the impact of Somorjai's work is to consider how far the reach of surface science extends. It may seem surprising that an incredibly thin skin—just a couple of atoms thick—can govern the properties of a large chunk of material. Yet that's exactly what happens in a number of disparate processes, many of which play a central role in industrially relevant technologies.
In petroleum and hydrocarbon chemistry, for example, chemical reactions on the surfaces of catalyst particles drive a large number of the transformations needed to produce fuels, chemicals, and other products. Such catalysis, known as surface or heterogeneous catalysis and long associated with Somorjai's name, also plays a key role in scrubbing automobile emissions and abating other forms of pollution. Similarly, chemical reactions on the surfaces of electrodes lead to power production in batteries and fuel cells and lie at the heart of electroplating and other electrochemical processes.
Other areas that would appear unrelated to classic surface science are in fact closely related because they, too, involve critical phenomena that occur on surfaces or at the interfaces of surfaces. For example, tribology—the science of friction, wear, and lubrication—is dominated by surface reactions. In one investigation in that area that's somewhat off the beaten path, Somorjai's group studied the structure and nature of ice crystal surfaces and tied those findings to ice's slipperiness and frictional properties. The study gained attention because it deepened understanding of that ubiquitous material and opened the door to applications related to ice hockey, skiing, and other cold-weather activities.
In fields such as tribology and the closely related area of corrosion, practitioners often focus on ways to customize the chemical composition and properties of surface layers to prevent damage caused by sliding contact between surfaces and by corrosive reactions. Similarly, tailoring surfaces by applying coatings or depositing thin films endows metals, glass, semiconductors, and other materials with just the right surface properties needed for applications in optics, microelectronics, and data-storage technologies. The same customizing principle holds true for materials used in medical implants and other biological applications.
Somorjai's main research focus for 40-plus years has been surface chemistry and catalysis. Yet the analytical tools, detailed surface models, and reaction mechanisms that his group has conceived, developed, or applied in new ways have also helped advance science and technology in a variety of fields that collectively depend on surface processes.
"There's no question that a lot of the concepts and terminology in classic surface science, some of which were developed in Gabor's lab, influence the way people think about phenomena in tribology, electrochemistry, and other surface processes," says Andrew J. Gellman, a tribologist and head of chemical engineering at Carnegie Mellon University. Gellman, who was a graduate student in Somorjai's group in the early 1980s, points to chemistry-induced reconstruction of crystal surfaces (alteration of lattice spacings) as one example of a universal and now commonly accepted concept that Somorjai championed and proved experimentally.
Another such concept, surface-structure sensitivity, addresses the dependence of the rates of some chemical reactions on the atomic structure, but not the composition, of the surface that mediates a reaction. Long ago, Somorjai's group showed that some hydrogenations, polymerizations, and other reactions proceed either exclusively or preferentially on a specific face of a crystal—for example the so-called (111) face of platinum—even though all of the faces are chemically, but not physically, identical. That idea, which nowadays researchers commonly invoke to describe surface-reaction mechanisms, plays an important part in efforts to improve catalysts and develop new ones.
Certainly no scientist, not even a highly successful figure like Somorjai, who has published more than 1,000 journal papers and three textbooks and who is a recipient of the National Medal of Science and the Wolf Foundation Prize in Chemistry, could be actively involved in all of the topics under the surface-science umbrella. "Yet even if Gabor didn't actively work in all of those fields, he certainly turned out students who do," says Northwestern University's Peter C. Stair, who was a graduate student of Somorjai's in the 1970s.
More than simply serving as branches that make up an expansive family tree, however, the 350-odd students and postdocs whom Somorjai trained carried away important lessons and strategies for conducting scientific investigations. "Their approach to science," says Stair, including himself in that group, "the way they frame problems in terms of molecular-scale surface phenomena, is directly related to what they learned from Gabor."
LIKE THE STATURE of some giants, scientific or otherwise, Somorjai's ultimate "height" or the fact that he would become a fellow of the American Association for the Advancement of Science and a member of the National Academy of Sciences would have been tough to predict in his youth. Not only wasn't this year's Priestley Medalist particularly interested in science as a 10-year-old growing up in Budapest, Hungary, he also wasn't especially conscientious about any of his school work at that age.
Somorjai recalls that at about that time, a school psychologist told his mother that "I had no aptitude for science or math" but noted that the boy was unusually advanced in the humanities. This is not surprising, Somorjai says, because "I didn't like school, but I loved to read. I read everything I could get my hands on—especially history and literature."
Surely the young Somorjai's apathy toward school could be attributed, at least in part, to the turmoil and tragedy experienced by his family and other Jewish Hungarian families during World War II. In the mid-1940s, the family business, a shoe store, was confiscated. Somorjai's father was forced into the Hungarian Army and later incarcerated in Mauthausen, a Nazi work and death camp in Austria. And the Somorjais were evicted from their home.
"By a stroke of luck," however, Somorjai says, his family was not among the thousands of Hungarians who were deported for slaughter at Auschwitz. Rather, they were among the fortunate ones who were permitted to move into Budapest's so-called protected houses through the efforts of Swedish diplomat Raoul Wallenberg. His father, too, was lucky. The senior Somorjai survived Mauthausen and made his way back home. Eventually, some semblance of normality returned to the Somorjai family.
As a teenager progressing through his high school years, Somorjai was a stellar student and "a pretty decent basketball player," he says. "I loved history and I liked to write and I wanted to become a historian." His pragmatic father, however, pointed out that in a small country like Hungary, jobs for historians were few. So the father advised his son to study chemical engineering, explaining that an education in that subject, which in European schools focused more on chemistry than engineering, would provide job security. Somorjai agreed and soon found himself at the Technical University of Budapest immersed in studies that he remembers as "challenging and difficult but very enjoyable."
IT WAS DURING his university years that Somorjai began to cultivate the experimental creativity that would later come to characterize his career as a professional scientist. Long before he began contemplating how to design surface analysis tools to probe molecular subtleties, Somorjai was troubled with a more pressing problem: how to make a little pocket money so he could afford to take a date out for dinner and an evening of dancing. Chemistry came to the rescue.
"I concocted liqueurs by fermenting sugar solutions and adding various flavorings," Somorjai reveals. He sold the sweet eggnog-like mixtures to friends of his family. He also ran a brisk trade in dyed stockings. In postwar Hungary, nylon hosiery was in short supply. Nylon thread, collected from frayed stockings, was woven into recycled stockings. "But they didn't look as good as new ones," Somorjai recalls. So he used a little chemistry know-how to prepare colorful dye solutions to spruce up the recycled products for sale. He also raised a little spending money by making and selling mercury thiocyanate "snake eggs." These egg-shaped novelty items entertained his customers by producing a black smoky snake when ignited.
It was also during that time that Somorjai met Judith Kaldor, who soon became his girlfriend. "I was just 16 when we started dating," Judy says with a smile and raised eyebrows, "and I was very proud to be going out with a university student." The young couple frequented theater and opera shows, went dancing, and worked together to sell Somorjai's homemade chemistry products.
All the while, Somorjai remained a diligent student and was on track to graduate with top grades. But in the fall of 1956, just a few months before graduation, the young couple fled their Soviet-controlled homeland together in the wake of the chaos and mass exodus that followed the Hungarian Revolution.
Within a few months, they immigrated to the U.S. and enrolled as chemistry students at UC Berkeley. That's when Somorjai began investigating platinum catalysts' surface properties because, as he puts it, "I found the subject intriguing but didn't know much about it." Shortly thereafter, the young immigrants were married and began to build a life in their new homeland. Except for a short stint during which Somorjai served as a research associate at IBM in New York, the couple has remained in Berkeley, where they raised two children, Nicole and John. They celebrated their 50th wedding anniversary last year with their children and four grandchildren, Stephanie, Clara, Benjamin, and Diana.
It's anyone's guess how far an apple will fall from its tree. In the Somorjais' case, it didn't fall far at all. Both Somorjai children studied chemistry, at least initially. John later switched to law and now works on the business-development side of a California high-tech company. John and his wife, Hilary, live in the San Francisco Bay Area. Nicole, a Ph.D. chemist, is married to Berkeley chemistry professor A. Paul Alivisatos, coeditor of Nano Letters. Nicole serves as the journal's coordinating editor.
LOOKING BACK at his career at UC Berkeley, now well into its fifth decade, Somorjai says he has been carried along all these years by his tenacity and perseverance, coupled with a desire "to move into new territories and out of my scientific comfort zone."
It's hardly surprising that the combination of those traits—inquisitiveness, tenacity, and a strong desire to explore the unknown—led Somorjai to become a dedicated scientist and a committed investigator. But what was he like as a mentor and research adviser?
"Fantastic," exclaims Paul S. Cremer without hesitation. Cremer, who was a graduate student with Somorjai in the 1990s and now is a chemistry professor at Texas A&M University, explains that Somorjai "had an uncanny ability to pinpoint exactly the heart of a problem." But in Cremer's experience, Somorjai didn't simply take control of a faltering investigation and solve problems unilaterally. Quite the opposite, Cremer says. "He would ask his students and postdocs just the right kinds of probing questions and let us think for ourselves. He always gave us plenty of room to grow."
That's exactly how Gellman at Carnegie Mellon remembers his years in Somorjai's group. "Gabor expected a lot from his students but gave us an enormous amount of freedom to design our own experiments," he says. And even though Somorjai was highly experienced, he would listen to the voice of reason from his young associates.
Gellman's favorite case in point involved his desire to purchase a tiny fraction of a milliliter of 35S-labeled CS2 for more than $4,000 (25 years ago) to conduct what he argued would be "exactly the experiment we need to do." Somorjai balked at the high price and kept putting off Gellman, who tried in various ways to convince his adviser to sign off on the purchase.
Finally, Gellman stressed to Somorjai that his roughly $1 million research budget produced 30-odd journal papers per year at a cost of some $30,000 per publication. "I argued that for just four grand we would get a paper and a really good one too." Reliving one of his "proudest moments in graduate school," Gellman, doing his best impersonation of Somorjai's Hungarian accent, recalls his adviser's response to that cogent argument. "Look, Andy. How can I win? Buy it." The resulting paper was published in the Journal of Catalysis.
GET A HANDFUL of Somorjai students to reminisce about him and they will quickly produce a list of attributes that characterize him as a skilled scientist and a wise mentor. But the list won't end there. "He was always a gentleman," Northwestern's Stair says, "very much the benevolent father figure."
More than 25 years after serving as a postdoc with Somorjai, Nicholas D. Spencer remembers him in much the same way. "It was clear that he really cared about his students personally," says Spencer, now director of the Materials Research Center at the Swiss Federal Institute of Technology, Zurich. Even as the years after leaving Somorjai's group turn to decades, Somorjai "continues to be incredibly supportive and interested in the success of his students' careers," Spencer relates. Gellman concurs, adding that Somorjai keeps in touch with many of his students from long ago and "is always ready to help."
Years of success in scientific research were met by extreme disappointment last year, when for the first time in more than 75 years the Nobel Prize in Chemistry was awarded for work in surface science, but it was not awarded to Somorjai. The decision to select just one winner came as a shock to the winner himself, Gerhard Ertl, professor emeritus at the Fritz Haber Max Planck Institute in Berlin. "It was really a surprise because my work is usually discussed with Somorjai's," Ertl told C&EN at the time (Dec. 3, 2007, page 60).
Somorjai responded that "Ertl is well-deserving of the prize." The longtime Berkeley scientist also expressed satisfaction that surface science, the subject matter upon which he built his scientific career, was acknowledged so prestigiously. Yet Somorjai's disappointment was unmistakable.
"It took a few months to get over it," Somorjai acknowledges with his characteristically warm smile and an upbeat tone, "but you have to move on." The lessons of his sometimes tumultuous life have taught Somorjai not to dwell in the past. And he's certainly not planning to.
"There's still so much work to be done," he says in a matter-of-fact way. "I'm privileged to be able to work at the frontier of an area of science that I helped pioneer. And I'm planning to do science as long as I can."
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