Abstract: Molybdenum trioxide (MoO₃) has a special structure,which is made up of the octahedral \[MoO₆\] basic structural unit,in which the Mo atom is in the center and oxygen atoms in the corner.Basic units are connected in a chain through sharing angles and every two similar chains are connected through sharing the sides to form layered MoO₃ stoichiometric structure.Layers are accumulated and arranged in a crisscross pattern under the action of the van der Waals force.This particular structure is very suitable for the embedment of other small molecules or ions and makes MoO₃ has good electrochromic,photochromic,catalytic,and gas sensing properties.Some common preparation methods of MoO₃ and applications thereof in optoelectronics,smoke suppression/flame retarding,catalysis,gas sensing materials and so on were introduced.In addition,the research progress in those areas by domestic and foreign scholars and the future development direction were also summarized.

Key words: molybdenum trioxide, electrochromic, smoke suppression