Cai Qirui




Cai Qirui (K. R. Tsai), physical chemist; professor of chemistry, Xiamen University (1956-); member of the Chinese Academy of Sciences (1980-). Born in Tong-an, Fujian Province in January 1914. B.Sc. (1937, Xiamen University); Ph.D.  in chemistry (1950, Ohio State University, USA). Cai has also served as vice-president of Xiamen University and chairman of the Academic Committee (1978-1992), director of the Research Institute of Physical Chemistry, Xiamen University (1979-1985); chairman (1987-1996) and honorary chairman (1996-) of the Academic Committee of the State Key Laboratory for Physical Chemistry of the Solid Surface; and a member of the Committee for the 8th International Congress on Catalysis (1984-1988).
Since 1957, Cai has focused his research interest on fundamental catalysis oriented towards the rational utilization of fossil fuel resources; since 1972 he has also been engaged in chemical modeling of nitrogenase catalysis and mechanistic study of ammonia synthesis over industrial iron catalysts. Since the early 1960s, Cai and his associates have developed the theoretical concept of coordination catalysis, summarized the “four possible effects" of coordination catalysis, and applied the principles of coordination catalysis to correlate various types of homogeneous catalysis, heterogeneous catalysis, and metallo-enzyme catalysis.
In the early 1970 to 1978, Cai and Lu Jiaxi pioneered internationally in proposing independently from slightly different approaches, slightly different cluster-structural models of nitrogenase active-center and multinuclear coordination of various types of the known substrates.  Since 1993, Cai and associates have proposed some new ideas about the structure-function relationship in nitrogenase catalysis, including the labile-mouthed M-cluster cage, the molecular recognition of substrates and inhibitors, the [Mo-3Fe-3Fe] monocapped trigonal-prism-mode of heptanuclear coordination of N≡N, and two proton-transport pathways from P-cluster to M-cluster cage via concerted proton tunnelling, based on the principles of coordination catalysis and chemical-probe experiments.
In methanol and ethanol syntheses over Cu-ZnO-based catalysts and Rh-MnOx-based catalysts, respectively, Cai have proposed that the promoter action of metal oxides lye mainly in lowering the energy barrier for the formation of formyl intermediate through charge-dipole interaction; Cai and associates have elucidated the reaction mechanisms for the main and side reactions of the two catalytic systems by means of in-situ chemical trapping, isotope methods, and FTIR spectroscopy. and pointed out that the experimental results of TPSR of preadsorbed CO on Rh-MnOx/SiO2 catalyst with D2 or H2 confirm the deuterium inverse kinetic isotope effect and the involvement of formyl intermediate in CO hydrogenation, and clearly indicate that linear CO is more reactive than bridging or tilted CO.
On oxidative coupling of methane (OCM) over irreducible rare-earth-alkaline-earth-based composite oxide catalysts, Cai and associates have shown mainly from in-situ Raman spectroscopy that O-2 is less reactive, but more selective than O2-2, and pointed out that O2-3 with in-situ Raman signal around 940cm-1 might be a precursor of O-2 during OCM reaction.  
Up to 1997, Cai (KR Tsai) has more than 200 publications to his credit as author or co-author.  In 1982, 1987, and 1995, Cai has led his research group to the winning of 3 national natural science awards of the third class.