N-Doped Graphene Aerogels Decorated by MoS2 Nanoflowers for Steam Generation under Low Solar Flux

As a spontaneous solar-thermal energy conversion technology with high photothermal efficiency, solar-driven interfacial evaporation has attracted enormous attention. However, considering the inadequate light illumination most of the time in a day and the expensive light-concentrating facilities, achieving high energy conversion efficiency under low solar flux is in great demand. In this work, we develop a broadband solar absorber based on graphene hybrid aerogels with MoS2 nanoflower decoration and nitrogen doping (MNGA). Synthesized via a two-step hydrothermal method, the porous MNGA shows self-floating ability, good thermal insulation, and a strong solar absorption of ≈93% in the visible to near infrared range. The nanoflower-like MoS2 decoration and nitrogen doping modulate the surface hydrophilicity jointly. Compared to nitrogen-doped GA , MNGA shows a reduced surface hydrophilicity, while still ensuring good wettability for water transport. Under low solar flux (0.3–1.0 sun), MNGA presents a high energy conversion efficiency (89.7–96.9%) and excellent cycling performance. It is endowed with good salt resistivity and recycling stability, maintaining an average efficiency of 96.6% under 1 sun illumination and stable performance during 10-cycle evaporation tests. These hybrid aerogels with outstanding photothermal performance, self-floating ability, salt resistivity, and durability offer a potential approach to realize water purification and desalination in daily life.