Green cellulose- based solar light capturing composite films made of carbon nanotubes (CNT) and cellulose nanofibrils (CNF), with high photothermal conversion performance, were designed and developed. Thanks to the strong electrostatic interactions between carboxyl- rich CNFs (obtained from 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO) mediated oxidation), and cationic-modified CNTs using cetyltrimethylammonium bromide, the resultant CNT/CNF composite (FTC) films are uniform and exhibit excellent mechanical properties. More importantly, the effect of CNT/CNF ratio in the FTC films on their photothermal conversion capacity and coefficient of thermal expansion (CTE) was investigated. The FTC film with 50 % CNT incorporation shows both high photothermal conversion capacity and high negative CTE, and its application for solar energy harvesting was explored, including seawater desalination, photothermal power generation and light- driven actuators. The FTC film exhibits high light-induced desalination capability, with water evaporation rate reaching 1.23 Kg m -2 h - 1 at an irradiance of 1 kW m - 2 (evaporation efficiency of 84.5 %) and ion concentrations in purified water decreasing by 4 orders of magnitude. The FTC film can also be assembled into photothermal power system, achieving an output voltage of 310 mV at an irradiance of 3 kW m - 2 . With the assistance of a boost module, it can be used to re-charge a cell phone. A light-driven FTC/polytetrafluoroethylene (PTFE) double- layered actuator was also designed. Benefiting from the negative CTE of the FTC film, the actuator has a high sensitivity and achieves a bending curvature of 3.3 cm - 1 at an irradiance of 0.74 kW m - 2 . This study presents a scalable, yet simple strategy to design green/sustainable cellulose- based solar energy harvesting devices that can have multiple applications.
With the increasing scarcity of freshwater resources and electricity, solar water evaporation and photothermal power generation are effective ways to solve energy shortages by utilizing renewable sunlight. However, current solar evaporators have low mechanical strength and evaporation rate . In this study, an interpenetrating network hydrogel evaporator with high mechanical strength, high water evaporation rate and photoelectric conversion performance was developed using galactomannan (GG), polyacrylamide (PAM), graphene oxide (GO) and Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs). Among them, PAM forms a three-dimensional cross-linking network structure with crosslinking agents, while the cis hydroxyl groups on the mannose branch chain in GG form a borate ester bond cross-linking network, enhancing the mechanical properties of the system; The GO and Fe 3 O 4 NPs uniformly dispersed in the evaporator can provide significant photothermal conversion efficiency for water evaporation. Under 1 sun irradiation, the water evaporation rate reaches up to 2.3 kg m −2 h −1 and conversion efficiency is 90.7 %. In addition, the combination of the hydrogel and the thermoelectric device module achieves thermoelectric conversion with a power density of 0.46 Wm −2 . Excluding losses in practical applications, the combined equipment could in the future heat the collected water to the required temperature to cope with extreme environments.
Lignin-based photothermal conversion materials provide effective solutions for advancing next-generation photothermal generators. However, recently reported lignin-based photothermal conversion materials face significant challenges due to poor mechanical strength, unstable solar energy collection, and difficulty in recycling. In response, high-performance photothermal materials based on lignin–tung oil covalent adaptive networks (LTs) are produced. The dynamic β-hydroxyl esters and multiple hydrogen bonds confer LTs with mechanical robustness, high adhesive strength, swelling resistance, and cycle processing performance. The π–π conjugation of aromatic rings imparts efficient photothermal conversion performance to LTs. Under xenon light irradiation (200 s, 1.2 W cm −2 ), LTs achieved a photothermal temperature exceeding 125°C. Furthermore, LTs demonstrated excellent maximum temperature stability over five light-heating and cooling cycles. The generator voltage remained stable within four cycles under leaf occlusion or real sunlight and could be artificially regulated when integrated into a thermoelectric generator. Consequently, the bio-based, mechanically strong, highly efficient, and stable-responding photothermal materials produced via a simple strategy hold significant potential for next generation solar thermal generators, suitable for industrial scale and large-scale production.
危险品化学品经营许可证（带存储）