Abstract: Quasi-homogeneous catalysts, composed of three-dimensional free metal nanoparticles in solvents and generally protected by a stabilizer, represent a growing branch of nanochemistry. Various quasi-homogeneous catalysts have been synthesized and applied to many catalytic reactions, exhibiting excellent catalytic performance under mild conditions. With versatile separation techniques, recycle of quasi-homogeneous catalysts can be realized.

Key words: quasi-homogeneous catalysis, nanocluster, soluble nanoparticle, ionic liquid, heterogeneous catalysis