Free-standing reduced graphene oxide (rGO) membrane for salt-rejecting solar desalination via size effect

Interfacial solar vapor generation has revived the solar-thermal-based desalination due to its high conversion efficiency of solar energy. However, most solar evaporators reported so far suffer from severe salt-clogging problems during solar desalination, leading to performance degradation and structural instability. Here, we demonstrate a free-standing salt-rejecting reduced graphene oxide (rGO) membrane serving as an efficient, stable, and antisalt-fouling solar evaporator. The evaporation rate of the membrane reaches up to 1.27 kg m−2 h−1 (solar–thermal conversion efficiency ∼79%) under one sun, out of 3.5 wt% brine. More strikingly, due to the tailored narrow interlayer spacing, the rGO membrane can effectively reject ions, preventing salt accumulation even for high salinity brine (∼8 wt% concentration). With enabled salt-antifouling capability, flexibility, as well as stability, our rGO membrane serves as a promising solar evaporator for high salinity brine treatment.