Abstract: Sequential and simultaneous methods of making a multi-metalized nanocomposite. A method includes providing a porous matrix, dissolving at least a first metal or metalloid precursor and a second metal or metalloid precursor in a supercritical carbon dioxide (CO2) fluid, wherein the first and second metal or metalloid precursors are different, infusing the supercritical CO2 fluid with the dissolved first and second metal or metalloid precursors into the porous matrix, lowering the pressure to trap the infused first and second metal or metalloid precursors in the porous matrix and reducing the first and second metal or metalloid precursors at an elevated temperature to form first and second metal or metalloid nanoparticles in the porous matrix.