Cai Qirui: "My favorite thing in my life is just a laboratory"

Cai Qirui (1913.12.3—2016.10.3), born in Tong'an, Fujian, is an academician of the Chinese Academy of Sciences and a famous chemist. In 1931, he was admitted to the Department of Chemistry of Xiamen University, stayed on to teach in 1937, and received a doctorate degree from The Ohio State University in United States in 1950, and later specialized in cesium oxide crystal structure. In 1956, he returned to China to teach at Xiamen University, and in 1958, he founded the first catalysis teaching and research department in a domestic university. In 1980, he was elected as a member (academician) of the Chinese Academy of Sciences, and served as the vice president of Xiamen University and a member of the discipline evaluation group of the first Academic Degrees Committee of the State Council. He has won the third prize of the National Natural Science Award of China for many times, and has won the "Senior Academician" and the "Ho Leung Ho Lee Foundation Science and Technology Progress Award".

Cai Qirui, the pioneer and founder of catalytic research and coordination catalysis theory in mainland China, has devoted his life to the research of catalytic theory, enzymatic and non-enzymatic catalytic nitrogen fixation, carbon-chemistry, light alkane chemistry and structural chemistry. He was the first to put forward the theoretical concept of complexation activation catalysis, systematically expounded the role of transition metal catalysts, and summarized four types of complexation catalytic effects, which enriched and developed the theory of complexation catalysis and had a significant impact at home and abroad.

Affection for Sangzi, with the national strategic needs as the mission

Cai Qirui stayed in Xiamen University after graduating from the Department of Chemistry in 1937, and moved to Changting with the school after the war, and taught for 8 years. During this period, he has demonstrated a high talent and enthusiasm for chemistry, spanning organic, structural, physicochemical, analytical, inorganic and other chemistry disciplines, and has been trusted by students and praised by colleagues. In 1947, at the recommendation of Lu Jiaxi, then dean of the School of Science and head of the Department of Chemistry at Xiamen University, Cai Qirui became one of the 20 people selected by the Chinese government to study in the United States at that time, and went to Ohio State University to specialize in physical organic chemistry, and obtained a doctorate in chemistry in only three years.

Cai Qirui was originally scheduled to return to his homeland immediately after completing his studies, but when the Korean War broke out in 1950, the United States government stipulated that all Chinese science and engineering students studying in the United States were not allowed to return to People's Republic of China, and Cai Qirui had to stay in United States temporarily, but he always cherished the motherland. In 1950, on the occasion of the 29th anniversary of Xiamen University, Cai Qirui sent back a telegram from the other side of the ocean: "The motherland is spring, I miss you, the motherland". At that time, Xiamen University was also planning for his return to the university, and Lu Jiaxi also proposed to the school to hire Cai Qirui as a full-time chemistry teacher and an instructor professor of the Institute of Chemistry. However, this letter of appointment was 6 years, and Cai Qirui wrote in a letter to his friend that "forgive this giant whale and can't muster up the waves", so he insisted on submitting an application for departure every year. Finally, in 1954, China and the United States signed the Geneva Agreement, and after negotiations, the mainland government exchanged United States prisoners of war for a group of scientists studying in the United States, and Cai Qirui was one of them.

In April 1956, Cai Qirui returned to his motherland on the steamship General Gordon, carrying only various experimental data and academic materials. During his time in the United States, he has made achievements in the field of physical organic and structural chemistry, and after returning to China, he continued to work on the polarization of ion crystals. However, in the face of the backwardness of the chemical industry and oil refining industry in the early days of the founding of the People's Republic of China, and the current situation that catalytic science was in a blank, he responded to the call of the country, started from scratch, devoted himself to catalysis research across borders, and established the first catalysis teaching and research department in a domestic university. In the first ten years in the field of catalysis, he successfully developed and industrialized two new catalysts, supported zinc oxide and niobium oxide, which laid the foundation for the breakthrough of acetylene rubber monomer technology.

Determined to innovate and work silently for the revival of Chinese science and technology

After 1972, Cai's research direction began to focus on chemical simulation of nitrogen fixation. At that time, with Zhou Enlai's approval, Chinese universities and research institutes began to resume basic research that had been stalled during the Cultural Revolution, and Cai Qirui, together with Tang Aoqing and Lu Jiaxi, academicians of the Chinese Academy of Sciences and masters of chemistry, formed an "ultra-luxury" interdisciplinary research team. The story of theoretical chemists, structural chemists and catalytic chemists working together to overcome the international academic problem of "chemical simulation of biological nitrogen fixation" is still a good story in the scientific community. Chemical simulation of biological nitrogen fixation is the process of using chemical methods to simulate the process of soybean rhizobia synthesizing ammonia directly from the air to produce nitrogen fertilizer at room temperature and pressure. It is necessary to first understand how nitrogen-fixing microorganisms in nature directly use nitrogen in the air to convert into ammonia at room temperature and pressure, so as to further improve the ammonia synthesis catalyst and improve the production efficiency of nitrogen fertilizer according to the principle. This was not only a scientific problem that the international community was trying to overcome at that time, but also a major problem that urgently needed to be solved in the construction and development of the mainland's countries, especially in the development of agriculture. After in-depth research, Cai Qirui elaborated on the mechanism of ATP-driven electron transport in enzymatic reactions, and proposed the single-cubisane model of nitrogenase active center with multi-nuclear atomic cluster structure earlier in the world (i.e., Xiamen model), and in the same year, Lu Jiaxi proposed the single-net-type model (i.e., Fuzhou model), which was later improved and evolved into the famous "Fujian model". In 1987, "Research on Nitrogen Fixation and Ammonia Formation under the Action of Nitrogenase and Iron Catalyst" was awarded the third prize of the National Natural Science Award, and the research on biomimetic nitrogen fixation by Cai Qirui's team was highly evaluated.

Cai Qirui is not only a chemist, but also a strategist for the development of energy and chemical industry, he advocated the energy and chemical route of "simultaneous development of oil, coal and gas, combination of combustion and chemical plastics" in view of the national conditions of abundant coal and relatively scarce oil and gas in the mainland, and advocated the optimization of fossil fuel utilization and the construction of an advanced energy and chemical system. In 1986, he joined hands with Academician Peng Shaoyi to organize scientific research across units and co-chaired the national major project of "Basic Research on Carbon-Chemistry". The project supports modern coal chemical industry, natural gas chemical industry and carbon dioxide chemical industry, promotes low-carbon energy utilization and resource utilization, and is the starting point of carbon-chemical research in mainland China, which is of strategic significance for energy security and sustainable economic development. The key scientific issues in carbon-chemistry are the mechanism of action and catalytic theory of catalysts, and the team led by Cai Qirui has detected carbon-species HCO, CH2, H2C=C=O and CH3CO and the mechanism of syngas to ethanol on Rh-based catalysts, which has been evaluated as one of the most important advances in carbon-chemistry in China, and has been widely recognized by peers at home and abroad, and the important achievement of the project, "Research on the Catalytic Mechanism of Syngas to Ethanol", won the first prize of the Science and Technology Progress Award of the Ministry of Education in 1994. In 1995, he won the third prize of the National Natural Science Award.

"Exploring the old and the old, determined to innovate and be strong." Lu Jiaxi commented on Cai Qirui. Cai Qirui once said, "My favorite thing in my life is just a laboratory" and "as long as I can still move and think, I will stand up and promote the research of these projects." At the age of 91, he sent a letter to Comrade Wen Jiabao, "Although Qirui is over 91 years old, I am still willing to use my limited waste heat to cheer for my young and middle-aged colleagues", and vigorously promoted the establishment of a national engineering laboratory for clean production of alcohol ether ester chemicals, hoping to contribute to the country's energy and chemical industry, especially coal chemical work, which fully demonstrates that Cai Qirui is a Nanqiang son who has no distractions all his life and silently takes the revival of Chinese science and technology as his own responsibility.

Sincerity and perseverance, teaching and educating talents

"Learning is like flowing water, and Derby is loose and green. Climb across the peak, cultivate brilliant stars. Tang Aoqing, a famous chemist, praised Cai Qirui's knowledge and morality. Cai Qirui was simple and rigorous all his life, indifferent to fame and fortune, and always put the interests of the country and the collective first. In 1999, shortly after Cai Qirui won the Ho Leung Ho Lee Foundation Science and Technology Progress Award and a prize of 200,000 Hong Kong dollars, he went straight to the college to donate the prize money for talent introduction. Considering Cai Qirui's living constraints and the illness of his family, Lin Yongsheng, then secretary of the Party Committee of the School of Chemistry and Chemical Engineering of Xiamen University, and his colleagues decided to quietly save the money in the name of Mr. Cai for emergencies. It was not until Cai Qirui moved that the college returned the passbook. In 2013, after consulting with his family, he once again supported the talent cultivation and scientific research development of the college through student donations. Student Chen Hongbin recalled that in 1983, Cai Qirui was sponsored by UNESCO to visit, and he used the savings of more than 3,000 US dollars to buy advanced PC/XT microcomputers for the team. At that time, computers were not widely used in China, and Cai Qirui's move was intended to hope that the team would keep up with the pace of the world.

Cai Qirui has also cultivated a large number of outstanding chemical research workers, making important contributions to the sustainable development of China's catalysis. He often said, "A disciple doesn't have to be inferior to a teacher", "Don't attribute the collective achievements to me, don't attribute the achievements of others to me", and practiced it personally. Student Wang Wei once recalled in "Memories of Mr. Cai Qirui" that Cai Qirui once read his experimental report in the laboratory and keenly discovered that this research was a pioneering scientific invention. Under the continuous guidance of Cai Qirui, the research was authorized by the national invention patent in 1992, but Cai Qirui resolutely did not agree to the joint signature, but helped him revise and improve the paper, down to the correction of punctuation, and the paper was finally published on multiple platforms.

On October 3, 2016, 104-year-old Cai Qirui passed away peacefully. His 100-year life is a vivid interpretation and glorious example of Xiamen University's motto of "unremitting self-improvement, stopping at perfection". catalysis, he is the founder; He is the leader in physical and chemical research; He is a pioneer in the development of engineering. Cai Qirui's rich scientific research achievements have laid a solid foundation for the progress and development of catalysis science in mainland China.