Recent progress in solar photothermal steam technology for water purification and energy utilization

Solar photothermal steam technology (SPST) has attracted increasing attention in recent decades because of great potential to produce fresh water from various water sources, such as seawater, rivers/lakes and sewage. Recently, lots of research has been carried out on the photothermal effect materials and rational structural design of SPST devices. The basis of photothermal conversion process, the design of efficient photothermal conversion materials-light collection, water transportation and heat management have been summarized. However, various preparation methods of SPST devices, the design and optimization of photothermal conversion system for improving steam generation rate and energy conversion rate still need to be further studied. The latest design and application of SPST are reviewed in this paper. Herein, photothermal effect, rapid water supply and fluent steam channels, and rational thermal management are identified as three key factors for efficient SPST. We propose a novel concept of “toolbox” to analyze SPST. Through this concept, the preparation method of photothermal effect materials is discussed, and the surface, structure and type of water supply materials are also analyzed, the strategies that have been used to optimize such issues are discussed. Furthermore, the influencing issues for thermal management to control heat loss and ensure maximum use of thermal energy for evaporation are discussed and combination of processing methods for SPST is summarized. Typical applications of SPST in desalination, wastewater treatment and energy generation are reviewed. Finally, challenges and key issues facing SPST are summarized, aiming to provide comprehensive understanding and guidance for the further development of SPST in clean water production and application.