Highly Effective\nMultifunctional Solar Evaporator\nwith Scaffolding Structured Carbonized Wood and Biohydrogel

Abstract

A solar evaporator that utilizes solar radiation energy\ncan be\na renewable approach to deal with energy crisis and fresh water shortage.\nIn this study, a solar evaporator was prepared by assembling composite\ncarbonized wood of Melaleuca Leucadendron L. and biobased hydrogel. The multilayer MXene (Ti₃C₂T_<i>x</i>) was embedded in the scaffolding\nstructure of the wood to form composite carbonized wood, where the\nloose and ordered scaffolding structure of the carbonized wood significantly\nimproves the efficiency of water transportation with increased capillary\nforce. The MXene adsorbed in the carbonized wood has high binding\nenergy with water molecules, leading to reduction of vaporization\nenthalpy and contact angle. Moreover, the addition of MXene can improve\nthe light absorbance, especially for the infrared and ultraviolet\nlight bands. The hydrogel was fabricated by crosslinking konjac glucomannan\nand sodium alginate polysaccharides with Ca²⁺, and it has\na lower thermal conductivity than water and improves the evaporation\nefficiency by regulating the temperature distribution and concentrating\nthe heat on the surface of the evaporator. This solar evaporator has\nan evaporation rate of 3.71 kg·m^–2·h^–1 and an evaporation efficiency of 129.64% under 2\nsun illumination and is available to generate an open-circuit voltage\nof 1.8 mV after a 20 min hydrovoltaic, demonstrating a high performance\nand versatility. Also, experiments and numerical simulation were carried\nout to understand the mechanism and design principles of this solar\nevaporators.