Enhanced Solar-to-Heat Efficiency of Photothermal Materials Containing an Additional Light-Reflection Layer for Solar-Driven Interfacial Water Evaporation

Solar-driven interfacial evaporation integrating inexhaustible solar energy and abundant seawater to address the scarcity of freshwater is a green and sustainable solution, but its industrial application remains challenging. Herein, a solar-utilizing device with a light-reflection layer was first proposed and fabricated for the improvement of light absorption as an efficient solar-driven interfacial salt-resistance evaporator, which consists of reduced graphene oxide-modified melamine sponge (rGOMS) (light-absorption layer) and aluminum foil (light-reflection layer). The strategy endows the assembled evaporator with high broadband light absorption (6.5% higher than that of the evaporator without a reflective layer), superior thermal insulation (0.0148 W m^–1 K^–1 in dry state), and continuous water transportation. Furthermore, the melamine sponge-based evaporator with a three-dimensional network structure (porosity of 99%) exhibits stable salt-resistance performance even in 20 wt % brine. As a result, the as-prepared evaporator (rGOMS-Re) has the merits of facile fabrication, durability, high cost-efficiency, and a stable photothermal evaporation efficiency of 87.5% under 1 kW m^–2 illumination (12.2% higher than that of the evaporator without a reflective layer) and has promise to be an ideal candidate for scalable practical application. The strategy to improve light absorption opens a new and simple route for obtaining photothermal materials with light loss.