Janus interpenetrating structure based on optimized water supply for solar-driven water evaporation

Realizing a balance between water supply and the evaporation of photothermal evaporators is a valuable means to enhance the solar–thermal evaporation rate, but practical obstacles remain. The interfacial mechanics of a Janus evaporator with an interpenetrating structure are proposed to achieve a dramatic improvement in the solar–thermal evaporation rate. The Janus evaporator is composed of a membrane material of Cu1.96S grown in situ on a foamed copper skeleton (CF@Cu1.96S) and a graphene oxide/sodium alginate aerogel (GA), through an interfacial freeze-drying shape technology. In this unique architecture, the superhydrophilic GA can be stretched into the hydrophobic CF@Cu1.96S interior to build an interpenetrating network architecture (CF@Cu1.96S/GA), thereby adjusting the Laplace pressure and constraining capillarity. Due to the optimized water supply of interfacial mechanics, the CF@Cu1.96S/GA evaporator achieves an evaporation rate of 1.79 kg m−2 h−1 under 1 sun irradiation and exhibits superior salt resistance. This provides a rationale for the reasonable design of the structure of the solar–thermal evaporators.