Kenzi Tamaru — A “titan of mechanism” who initiated the in-situ study of catalysts
On July 22, 2020, the scientific community lost Kenzi Tamaru, a pioneer in elucidating the mechanisms of heterogeneous catalytic reactions. His enduring legacy will be his insight that catalysts have to be studied at reaction conditions. This insight was the basis for the now widespread use of in situ and operando studies in catalysis.
Kenzi Tamaru was born in Kamakura, Japan on Nov. 2, 1923, and was educated at the University of Tokyo, obtaining his B.S. in 1946, and his Ph.D. in 1950. In 1953 he was awarded a Fullbright Fellowship and went to work with Sir Hugh Taylor at Princeton University where he stayed until 1956. In Princeton Kenzi studied the decomposition of germane and got the insight of the need to study catalysts at reaction conditions. When he told Prof. Taylor of this concept he said “You are very ambitious”, repeating it, “You are very ambitious”. On returning to Japan, Kenzi started research on adsorption during catalysis, first at Yokohama National University, and then at the University of Tokyo. In Adv. Catal. 15 (1965) 65–90, he stated “The state of the surface which catalyzes reactions is not that of the surface in the absence of reactants. The properties of a catalyst surface to be studied should be those in the working state.” Today, the need to study catalysts at in situ conditions is universally recognized and is applied regularly using spectroscopic and transient techniques. Kenzi Tamaru liked to tell his students, “You have a good head, so think carefully”. This thinking was evident in him at an early stage. His grade school teacher recalled that when students were asked to name something that would not burn most students answered with things like stones or steel. Kenzi’s unique answer was “ashes”. Kenzi Tamaru’s application of what he liked to call “the Tamaru Method”, included in situ studies of MeOH decomposition on ZnO and Cr2O3, NH3 decomposition on W and Mo, and CO hydrogenation on Ru, and the phenomenon of adsorption-assisted desorption. Kenzi had close friendships with many distinguished individuals in the field, notably Michel Boudart, Wolfgang Sachtler, and Guo Xiexian, with whom he shared a common interest in chemical kinetics as well as personal relations. Kenzi Tamaru held many important positions including the presidencies of the Japan Chemical Society in 1989–1990, and the International Association of Catalysis Societies in 1988–1992. He was recognized with many awards, including the Japan Chemical Society Award in 1974, the Purple Agate in 1985, and the Japan Academy Award in 2000.
His presence will be missed but his contributions will endure.