Electrochemical Preparation of Graphene Membrane for Continuous Water Vapor and Crystalline Salt Production

Graphene has high application value in photothermal conversion fields because of the thinness, ultra‐lightness, and excellent photothermal properties. However, the traditional methods for preparing commercial graphene were less efficient and more expensive. Herein, the graphene suspensions were prepared using a convenient and environmentally friendly electrochemical exfoliation method. The graphene photothermal conversion (E‐GR) membranes were obtained to investigate the effect of electrochemical preparation conditions on the photothermal conversion performance. The evaporation rate of E‐GR membrane was 1.267 kg m −2 h −1 under 1 sun, achieving a solar‐to‐steam conversion efficiency of 79.65%. In the continuous salt crystallization experiment, the E‐GR membrane achieved desalination and uninterrupted fresh water and salt production for 7 days, resulting in the generation of 23.451 kg m −2 d −1 fresh water and 0.654 kg m −2 d −1 crystalline salt. During this period, the crystalline salt was formed only at the edges with no obvious crystallization on the surface. Because of the characteristic that graphene can provide a large number of adsorption sites, combined with the capillary action of filter paper, the membrane can be wetted in a short time. Overall, this simple, cost‐effective and efficient preparation method greatly promotes the application of graphene in the field of seawater desalination.