Solar driven cogeneration of freshwater and electricity based on an Al2O3 nanoparticle decorated graphene aerogel

Abstract

The combination of solar water evaporation and the hydrovoltaic effect (HVE) provides an effective way to solve the crisis of water shortage and fossil fuel pollution. However, there are still challenges faced such as the low output power, slow water evaporation, and high salt accumulation. Here, we design a three-dimensional (3D) Al₂O₃-decorated graphene aerogel (AGA) that can effectively collect fresh water and electricity simultaneously. The AGA prepared by the freeze-drying method has vertical channels, a loose porous structure, and strong hydrophilicity. Moreover, the hydrated ions introduced by Al₂O₃ lead to strong zeta potential in the channel, thereby resulting in excellent electricity generation capacity. In seawater, the water evaporation performance reaches 3.03 kg m⁻² h⁻¹; meanwhile, the maximum output voltage is about 0.76 V with output electrical power density reaching 38 mW m⁻².