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In recent years, pursuing a high evaporation rate of solar steam generation (SSG) has been the focus of research for relieving the freshwater shortage. Scientists struggled to find perfect photothermal materials while the importance of substrate during the steam generation was often overlooked. Therefore, in this work, an aerogel substrate composed of polyvinyl alcohol (PVA) and chitosan (CS) has been designed for solar steam generation. The compounded aerogels synthesized via freeze‐drying method not only retain the inherent characteristics of lightweight, porosity, and high specific surface area, but also inherit the advantages of PVA in water lock effect as well as CS in moisture absorption. The obtained PVA/CS/CuO aerogel coupling with high light absorption of CuO exhibited excellent steam generation capabilities, largely benefited from the superiority of the aerogel substrate. Under 1 sun solar illumination (1 kW m–2), it realized an evaporation rate as high as 2.14 Kg m–2 h–1, which is superior to recently reported semiconductor solar evaporation system. The solar‐to‐vapor energy conversion efficiency of 87.1% is obtained. Due to the versatility of CuO, PVA/CS/CuO aerogel not only has excellent light‐to‐heat conversion performance, but also has good effects in antibacterial. [ABSTRACT FROM AUTHOR]

Solar steam generation is an environmentally friendly water treatment method that produces clean water using solar energy. However, it is still a challenge to effectively prevent the performance deterioration when most photothermal conversion materials are used to evaporate high‐concentration salt‐containing wastewater or strong acid/alkali solution. Herein, a stable and effective solar evaporator is designed using natural sugarcane, where sucrose is simply dehydrated into carbon particles by hydrothermal reaction in sulfuric acid. With a honeycomb structure, it not only enables water transport capacity but also promotes sunlight absorption. Sulfuric acid hydrothermal carbonized sugarcane (SHCSC) can reach up to 95.36% solar absorption in a wide wavelength range (200–2500 nm) and a high evaporation rate of 2.32 kg m−2 h−1 under 1 sun illumination. More importantly, SHCSC has an excellent adsorption capacity with ion removal rate of 99.9% even under artificial wastewater containing 1000 mg L−1 of mixed metal ions. SHCSC also can perform efficiently and stably at a high evaporation rate above 2.2 kg m−2 h−1 in strong acidic or alkaline wastewater. These findings suggest that SHCSC can be potentially applied to the efficient harvest of clean water from the high‐concentration wastewater containing acid, alkali, and mixed metal ions. [ABSTRACT FROM AUTHOR]

The solar‐assisted desalination generator (SADG) shows great potential for solving water scarcity problems. However, salt precipitation and accumulation is still a challenge for SADG, which slows down solar steam generation performance of evaporator during operation. Here, a facile integrative evaporator featuring stable and high evaporation performance breaks this bottleneck. By using a rational design in which amorphous carbon particles are evenly composited within the porous chitosan aerogel, the evaporator not only integrates excellent light absorption, heat management, and water transportation abilities but also endows a large vapor escape space. Upon desalination, salt concentration ingredients between carbon particles and chitosan membranes can be quickly balanced by water transport in interconnected chitosan chains, and thus salt precipiation on the evaporator surface would be avoided. Compared to other salt‐rejection evaporators, the integrative evaporator can operate in 3.5 wt% brine for 60 days without salt precipiation and exhibits a stable evaporation rate (1.70 kg m−2 h−1), indicating its potential for practical applications in seawater desalination and the harvest of clean drinking water. [ABSTRACT FROM AUTHOR]

Energy matching strategy is verified as an effective method for significant improvement of evaporation rate in direct solar steam generation (DSSG). By adjusting the solid–liquid interface through bilayer structure, the water transport speed from reservoir to evaporation surface is controlled to reduce the required energy (RE) for closely matching with that of input energy (IE). The highest evaporation rate can reach up to 2.22 kg m−2 h−1 under one‐sun illumination, which is improved by 40% through energy matching. A solar‐to‐vapor energy conversion efficiency of 93.2% is obtained. It is also highly effective in practical applications including desalination, sewage treatment, oil–water separation, and heavy metal ions treatment. This concept displays a balance between the energy needed for water waiting to be evaporated and the IE. It can inspire more ideas for researchers to accelerate the development of DSSG. [ABSTRACT FROM AUTHOR]

Direct solar steam generation (DSSG) offers a promising, sustainable, and environmentally friendly solution to the energy and water crisis. In the past decades, DSSG has gained tremendous attention due to its potential applications for clean water production, desalination, wastewater treatment, and electric energy harvesting. Even though the solar–thermal conversion efficiency has approached 100% under 1 sun illumination (1 kW m−2) using various photothermal materials and systems, the optimization of the materials and system structure remains unclear because of the lack of evaluation methods in unity for the output efficiency. In this review, a few key concerns about different dimensional materials and systems that determine the characteristics of DSSG are explored. Quantitative analysis, including calculations and methods for the solar–thermal conversion efficiency, evaporation rate, and energy loss, is employed to evaluate the materials and systems from the point of view of ultimate utilization. This article focuses on the relationship between the system dimension and energy efficiency and notes opportunities for future system design and commercialization of DSSG. [ABSTRACT FROM AUTHOR]