Enhanced Efficient Solar Evaporation of Co/CoO Loaded on the Tobacco Stem Under Visible Light

Abstract Solar‐driven water evaporation is an emerging technology in green technology of seawater desalination and sewage treatment. However, the quality of high cost, complex manufacturing, and a small amount of synthetic materials is the main obstacle to large‐scale applications. Biological carbon‐based materials have a large and efficient heat exchange area due to the naturally abundant pore structure, which plays an important role in regulating convection and radiant heat loss. However, single‐component carbon materials have limited photothermal conversion performance, which limits their large‐scale application. In this work, tobacco stem (TS) organisms loaded with Co/CoO nanoparticles are successfully prepared by one‐step pyrolysis. The synergistic effect of Co/CoO nanostructures and biocarbon materials enhances water evaporation performance, widening the absorption range of the material across the entire solar spectrum, and expanding the range of energy that can be converted into heat. Specifically, the water evaporation rate and photothermal conversion efficiency of TS ‐Co/CoO (0.20) reached 2.22 kg m⁻² h⁻¹ and 139.4%, respectively, and its evaporation rate is 1.7 times the direct carbonized tobacco and 4.35 times the pure water. This work provides a research idea for the multifunctional and effective utilization of waste biomass materials and the construction of bionic structure solar photothermal materials.