Environmentally benign preparation of metal nano-particles by using water-in-CO2 microemulsions technology

Water-in-CO2 (W/C) microemulsion technology offers a new environmentally friendly approach for the synthesis of a variety of metal nano-particles in supercritical CO2 using water-soluble reagents as starting material. W/C microemulsions have unique advantages over conventional water-in-oil (W/O) microemulsions because of the use of environmentally benign, cheap, and recyclable CO2 as the continuous phase in place of organic solvents. In this review, we will discuss some recent progress on the preparation and applications of metal nano-particles prepared in W/C microemulsions.