Study of Metal–Graphene Aerogel for Efficient Solar Energy Interface Evaporation Based on One‐Step Thermal Reduction Method

Abstract

Freshwater resources can be sustainably harvested through interfacial evaporation by solar energy. To enhance the efficiency of solar interfacial evaporation, a metal–graphene alcohol gel is synthesized using a one‐step thermal reduction technique. Subsequently, a metal–graphene aerogel (GA) is produced using freeze‐drying technology. The hydrothermal treatment method is applied to introduce asymmetric moisture and roughness on the upper and lower surfaces of the aerogel. The unique structure of the aerogel plays a significant role in facilitating continuous water transport to the interface for evaporation. The top layer, being hydrophobic, and the bottom layer, being hydrophilic, contribute to this process. Importantly, the top layer's design ensures that an excessively thick water film does not form, thereby preventing any adverse effects on light‐absorption efficiency. The aerogel exhibits that an outstanding water‐evaporation rate is 1.75 kg m−2 h−1 and a remarkable photothermal conversion efficiency (PTCE) is 93.17% under one solar radiation intensity. This is because the aerogel has a unique 3D structure. This special 3D structure has an interconnected microporous‐like appearance inside, which increases the evaporation area. Metal–GA is based on the electric field dielectric evaporation mechanism of metal nanoparticles localized surface plasmon resonance effect and the thermal mediated evaporation mechanism of graphene full spectrum. Under the double action, the PTCE is significantly improved. The meticulously created metallic GA performs exceptionally well at evaporating water. As a result, it presents a promising and practical avenue for exploring effective solar interfacial evaporation.