According to the present invention, there are provided processes for preparing a porous composite material comprising a metal and a two-dimensional nanomaterial. In one aspect, the processes comprise the steps of: providing a powder comprising metal particles; heating the powder such that the metal particles fuse to form a porous scaffold; and forming a two-dimensional nanomaterial on a surface of the porous scaffold by chemical vapour deposition (CVD). Also provided are materials obtainable by the present processes, and products comprising said materials.