Solar‐Powered High‐Performance Lignin‐Wood Evaporator for Solar Steam Generation

Abstract

Recent research on wood‐based solar evaporators has made great progress and significant breakthroughs have been made in using lignin as a photothermal material; however, the intensity change mechanism regarding the conjugate structure of lignin is almost never mentioned. This study innovatively proposes a mechanism to explain the changes in conjugate intensity that occur before and after lignin dissolution and fabricates a lignin/wood‐based solar evaporator (LWE) using an all‐wood‐based material that is salt‐tolerant and has long‐term serviceability. Lignin in the evaporator serves not only as a photothermal material for converting light energy into heat energy but also as a reinforcement for the evaporator's structural strength. Adding lignin changes the original structure of balsa wood, increasing the proportion of intermediate water in the LWE, thereby lowering the enthalpy of water evaporation. The optimized LWE with an enhanced desalination capability, dye removal property, and high stability exhibits full‐spectrum solar absorption of about 83.6%, a photothermal conversion efficiency of 91.74%, and an evaporation efficiency of 1.93 kg m ⁻² h ⁻¹, which surpasses most wood‐based evaporators. This study demonstrates that all‐wood‐based materials can be used to prepare evaporators with excellent performance, providing a new approach to address freshwater depletion.