ROBERT J. MADIX (1938-2023)

BY CYNTHIA M. FRIEND
SUBMITTED BY THE NAE HOME SECRETARY

ROBERT JAMES MADIX, a pioneer in surface science and catalysis, the C.J. Powell Professor of Chemical Engineering Emeritus at Stanford University, and senior research fellow in the Paulson School of Engineering and Applied Sciences at Harvard University, passed away at the age of 84 on May 25, 2023. He was a visionary scientist, a gifted athlete, and a great storyteller.

Robert, more commonly called Bob, was born in Beech Grove, Indiana, on June 22, 1938. He was the first child of Marjorie Strohl Madix and James Madix, who were high school sweethearts. In his early years, Bob moved frequently as his father served in the Army during World War II. After the war, the family returned to their hometown of Champaign, Illinois, where their relatives still resided.

Bob excelled academically but often found school unstimulating. He channeled his energy into sports, particularly baseball. He was a standout player at Champaign High School, where he was inducted into the hall of fame. He later played at the University of Illinois while excelling as a chemical engineering student. One of his proudest accomplishments was winning the Big Ten Medal of Honor in 1960. During college, he was scouted by professional baseball teams but chose to pursue chemical engineering, in part because engineers earned higher salaries than professional athletes at the time.

He graduated with honors with a bachelor’s degree in chemical engineering from the University of Illinois Urbana-Champaign in 1960. During his studies, he completed several summer internships, including one at Exxon in New Jersey. Though he considered several industrial positions, he realized that research was his true calling.

He was admitted to the chemical engineering graduate program at the University of California, Berkeley, where he worked with Michel Boudart (NAE 1979), a leading figure in catalysis and a member of the National Academy of Sciences. Madix earned his Ph.D. in 1964, focusing on silicon etching. He built a highly sensitive mass balance instrument that could operate unattended, as the mass changes he measured were minuscule and required long observation periods. His automation relied on a chart recorder, as computers were not yet available for such applications. With his research running in the background, Bob found time for other pursuits, including intramural sports. During this period, he married his college sweetheart, Camille. Their son, Bradley, was born in 1962 in San Francisco while Bob was still a graduate student.

Bob was inspired to develop a molecular-level understanding of heterogeneous catalysis as he witnessed advances in modern tools and quantum chemical methods. In 1964, he spent a year as a National Science Foundation postdoctoral research fellow in Manfred Eigen’s (NAS) lab at the Max Planck Institute in Göttingen, Germany. His research on nickel oxidation faced challenges due to contamination issues, leading him to explore ultrahigh vacuum technology for surface chemistry investigations. At the encouragement of Boudart, Bob traveled across Europe to learn about the latest advancements in catalysis and instrumentation. The limitations of his postdoctoral research further motivated him to apply ultrahigh vacuum technology to studying surface chemistry on well-defined, single-crystal surfaces. At the time, key catalytic reaction mechanisms—such as formic acid decomposition on nickel—were poorly understood, shaping his future work.

Madix began his independent career in 1965 as a faculty member at Stanford University, joining a new department founded by David Mason. Boudart and Andreas Acrivos (NAE 1977, NAS), a leader in fluid mechanics, had joined the department the previous year. With limited startup funding, Bob built ultrahigh vacuum equipment and used mass spectrometry and molecular beam methods to study reaction kinetics, receiving support from Boudart. That same year, Bob and Camille welcomed their second son, David.

From 1969 to 1972, Bob was appointed a Ford Foundation Fellow, giving him additional responsibilities and the freedom to experiment with innovative teaching methods. This period coincided with the Vietnam War, which caused unrest on campuses nationwide, including Stanford. The war also impacted his research group, as two of his graduate students were drafted. One of them, John Falconer, returned after his service and made significant contributions to the development of temperature programmed reaction spectroscopy, a key tool for obtaining rate constants for surface reactions.

Madix was granted tenure in 1973, though the process was not without controversy. Some faculty were skeptical of his emerging research, as he was pioneering new methodologies. His tenure case ultimately reached Stanford’s provost, who, after reviewing highly supportive external letters, interviewed Bob directly. Convinced of the work’s impact, the provost approved his tenure. Bob’s political activism as a Ford Fellow had also made tenure discussions more complex. The stress of this period affected him personally, leading to his divorce from Camille. Despite this, they remained friends throughout his life.

Following tenure, Madix and his research group published groundbreaking studies on surface chemistry related to selective oxidation catalysis. His work on methanol and formic acid reactions on copper and silver remains widely cited. He introduced the concept that oxygen atoms bound to silver and copper act as Brønsted bases, facilitating reactions with hydroxyl groups in alcohols and organic acids to initiate catalytic cycles for selective oxidation. He demonstrated this mechanism through isotopic labeling and temperature programmed reaction spectroscopy. His team later extended this paradigm to oxygen-induced reactions of thiols and amines. These studies not only advanced the understanding of oxidation catalysis but also established benchmarks for spectroscopy methods, including vibrational spectroscopy (infrared absorption reflection and high-resolution electron energy loss), X-ray photoelectron spectroscopy, and near edge X-ray absorption fine structure (NEXAFS).

Madix was awarded a senior research fellowship by the Humboldt Foundation in Germany. He spent his sabbatical at Ludwig Maximilian University in Munich in 1980, where he collaborated with Gerhard Ertl (Nobel Prize in Chemistry, 2007; NAS) and engaged in lively discussions with Dietrich Menzel, another leading figure in the emerging field of surface science. This period further established his reputation on the international stage and marked the beginning of a prolific phase in his research career.

The Madix group established key principles governing surface chemistry using various kinetic and thermodynamic methods, including temperature programmed reaction spectroscopy, molecular beam scattering, Kelvin probe measurements, and temporal analysis of products (TAP). Bob was an early adopter of molecular beam techniques in surface science, having been a graduate student at Berkeley during the advent of molecular beam methods for the study of gas phase reactions. His work demonstrated the presence of dynamic states for adsorption that involved the conversion of normal to parallel momentum. He also investigated the dissociation of hard-to-react molecules, such as nitrogen and alkanes, using high kinetic energy molecular beams on nickel and platinum surfaces. His contributions in this field were widely recognized as pedagogical.

Bob was always quick to adopt new tools to advance the understanding of surface chemistry. In addition to his early use of surface spectroscopy, he pioneered the use of scanning tunneling microscopy (STM) to study surface reactions, including oxygen-induced dissociation reactions. His STM work established that metal surfaces undergo structural rearrangement during surface reactions — a principle now widely accepted but controversial at the time. His groundbreaking research on the massive restructuring of copper surfaces during the oxidation of ammonia exemplified this discovery.

Madix played a major role in the growth and development of the Chemical Engineering Department at Stanford, serving as department chair from 1983 to 1987. He introduced novel ways to support faculty, including providing some of the first personal computers to faculty members. A strong advocate for gender equity, he was pivotal in recruiting a diverse and talented faculty.

Madix married Barbara Slatkin, and they had two children, Michaella and Evan, in 1983 and 1985. After their divorce, he formed a relationship with Cynthia Friend, a colleague at Harvard. Given that they worked in the same field, it was nearly impossible for them to secure tenured faculty positions at the same institution. They maintained a long-distance relationship between Stanford and Harvard, often meeting at scientific conferences around the world. Despite these challenges, they married and remained devoted life partners until his passing.

Madix accepted early retirement from Stanford in 2004 and moved his lab to Harvard as a research professor in the Paulson School of Engineering and Applied Sciences. Beginning in 2005, he embarked on a second prolific career. He relocated equipment and a small research group to Harvard, where he focused on single crystal surface chemistry, particularly silver chemistry. His work was complemented by other work on gold at Harvard and at Lawrence Livermore National Laboratory, and on nanoporous gold, a dilute silver-in-gold alloy, at Bremen University.

At Harvard, Bob was a key member of a small group of scientists who envisioned an innovative research program integrating fundamental surface chemistry with operational catalysis. This vision led to the successful establishment of an Energy Frontier Research Center (EFRC) grant, funded by the Department of Energy, to support sustainable catalysis research. As part of the EFRC, Madix focused on selective oxidation reactions on dilute silver-in-gold alloys, building on his earlier work. This research culminated in a 2018 Nature Catalysis paper¹ that demonstrated the ability to predict reaction selectivity across six orders of magnitude in pressure and several hundred degrees of temperature. The study used mechanisms and rate data obtained from surface chemistry experiments on well-defined crystalline surfaces. Key kinetic data were obtained using the TAP method and flow reactors. This work was the first of its kind, establishing a methodology for predicting and understanding catalytic reactions.

Throughout his career, Bob prided himself on being a Socratic teacher. He served as an advisor and mentor to students and postdoctoral researchers for six decades at both Stanford and Harvard. Many of his mentees, as well as their students and subsequent generations, have gone on to become leaders in industry, education, and research. His influence on the field of chemical engineering extended through both education and research.

Bob’s election to the National Academy of Engineering came late in life. He was elected in the class of 2022 “for development of quantitative models for predicting catalytic selectivity through fundamental understanding of reaction mechanism and kinetics.” He received numerous other honors including the American Chemical Society (ACS) Gabor A. Somorjai Award for Creative Research in Catalysis, the ACS Adamson Award in Surface Chemistry, the Alpha Chi Sigma Award for Chemical Engineering Research of the American Institute of Chemical Engineering, the Paul H. Emmett Award in Fundamental Catalysis from the North American Catalysis Society, and the Henry J. Alpert Award from the International Precious Metals Institute. In 2022, he was awarded the Langmuir-Gaede Award by the American Vacuum Society (AVS) for “ground-breaking research that advanced the development of surface science for understanding complex surface reactions and their relationship to heterogeneous catalysis.” Madix was also a fellow of the ACS and the AVS.

Bob is survived by his wife, Cynthia Friend; his children, Bradley Madix, David Madix, Michaella Madix, and Evan Madix, and his stepdaughter, Ayse Gurdal-Friend. He is also survived by his former spouses, Camille Andre and Barbara Slatkin; his grandchildren, Danielle Madix, Austin Ohel, Beau Wilson, and Asher Wilson; and his great-granddaughter, Mira.

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¹Reece C, Redekop EA, Karakalos S, Friend CM, Madix RJ. 2018. Crossing the great divide between single-crystal reactivity and actual catalyst selectivity with pressure transients. Nature Catalysis 1:852-9.