Enhanced photothermal PVA aerogel containing “nut-cake-like” filler consisting of edge oxidized graphene and liquid gallium for efficient solar steam generation

Abstract

A solar steam generator (SSG) is an effective method for solving water shortages and protecting the environment, but its evaporation rate remains limited. Herein, Ga@EOG/PVA aerogel-based SSG with excellent photothermal seawater purification capabilities was prepared using liquid metal gallium (Ga), edge oxidized graphene (EOG), and polyvinyl alcohol (PVA). The “nut-cake-like” structure formed by electrochemical oxidation of EOG encapsulated Ga nanoparticles enhances light absorption and heat conversion efficiency through multiple light scattering and surface plasmon resonance. Furthermore, the vertical pore structure of the aerogel mimics the xylem conduit in tree trunks, allowing rapid transmission of heat and water, thus increasing its evaporation capacity. Based on these attributes, the SSG demonstrated a light absorption rate of 98.2% and an evaporation rate of 5.13 kg·m⁻²·h⁻¹ under one-sun illumination, surpassing previously reported values in the literature. Moreover, the SSG effectively treated heavy metal salts, organic dyes, wastewaters, and acidic or alkaline solutions. These findings highlight the potential effectiveness of the prepared aerogel for numerous of environmental remediation applications, especially in ensuring high water quality and safety for human consumption.