Controlled synthesis of Ag nanowires and nanoparticles in mesoporous silica using supercritical carbon dioxide and co-solvent

► Mesoporous silica supported silver nanocomposites were synthesized using scCO2 as solvent. ► Low price AgNO3 instead of organometallic compound was used as precursor with the addition of a little appropriate co-solvent. ► The metal loading achieved 26.97 wt% when the deposition time was only 1 h. ► Nanowires were successfully confined in the channels of MCM-41 with an average diameter of 2-3 nm.