Choy received his B.S. (1971) and M.S. degrees (1973) in chemical engineering from Yonsei University in Seoul. Afterwards he received a diploma in 1975 from the UNESCO postgraduate course in chemistry and chemical engineering, research laboratory of engineering materials, Tokyo Institute of Technology, Japan. He then moved to Germany, where he earned his PhD (1979) in inorganic chemistry at the Ludwig Maximilian University of Munich.