A general and facile method for preparation of large-scale reduced graphene oxide films with controlled structures

Graphene or reduced graphene oxide films (rGOFs) can be prepared by a number of methods including chemical vapor deposition (CVD), filtration, and spin-coating for a variety of applications. However, controlling their surface morphologies and microstructures to meet the requirements of specific applications is still a great challenge. Here, controlled microstructure of large-size rGOF with good electrical and thermal conductivities as well as high sorption ability is produced through a heating-assisted spray method. By simply tuning the heating temperature, the smooth surface and close-packed layered structure of rGOF can be changed to rough surface and porous structure. Impressively, the rapid preparation of rGOF with area as large as ∼216 cm² in only 6 h has been successfully achieved, which is significant since normally it takes several days to prepare a rGOF with small area of ∼10 cm² by using conventional filtration method. More importantly, our rGOFs show promising applications in oil sorption, supercapacitors, and thermally/electrically conductive films.