Applications of supercritical carbon dioxide in materials processing and synthesis

Supercritical carbon dioxide (scCO2) is carbon dioxide that is held beyond supercritical conditions of 31.1 °C and 7.4 MPa. As a non-toxic and environmentally benign green solvent, it has been widely used in the food and pharmaceutical industries for extraction. However, scCO2 also has many unique properties and thus has great potential for advanced, green materials processing. This concise review focuses on its use as a solvent and an anti-solvent in materials processing and synthesis. Different experimental routes are described that are used to synthesize bulk materials, thin films, coatings, particle suspensions and powders. Examples from the literature are highlighted to illustrate the different experimental set-ups and applications of the resulting materials. This review endeavours to reveal the potential and versatility of scCO2 in materials processing and synthesis, aiming to encourage a wider application of scCO2 to open more opportunities in innovative green processing of both traditional and functional materials.