▎ 摘　　要

NOVELTY - Preparation of graphene photothermal film with double-layer structure comprises depositing graphene oxide film on substrate, and using flash lamp for flash reduction of surface layer of graphene oxide film to obtain graphene photothermal film of graphene layer with three-dimensional hole structure and graphene oxide layer with two-dimensional layered structure. The energy density of the flash lamp is 0.5-1.0 J.cm2. The flash reduction time is 0.5-200 ms. The flash distance of graphene oxide film is less than 3 cm. The thickness of graphene oxide film is 80-1500 nm. USE - The method is for preparation of graphene photothermal film with double-layer structure used for solar seawater desalination and in seawater desalination device (all claimed). DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) graphene photothermal film with double-layer structure comprising graphene layer of three-dimensional hole structure and graphene oxide layer of two-dimensional layered structure, where the thickness ratio of graphene layer and graphene oxide layer is 100:1-1:1; (2) application of the graphene photothermal film with double-layer structure in solar seawater desalination, comprising under irradiation of sunlight, contacting the graphene oxide layer or substrate of two-dimensional layered structure and desalting seawater; and (3) seawater desalination device comprising graphene photothermal film with double-layer structure, supporting structure for supporting the graphene photothermal film, seawater container for containing seawater, seawater injection device for supplementing the seawater into seawater container, light-transmitting steam collecting device, which is set above the graphene photothermal film, for condensing and collecting the generated water vapor, and fresh water collecting device for collecting fresh water collected by the light-transmitting steam collecting device.