Steam generation enabled by a high efficiency solar absorber with thermal concentration

Highlights: • C-Au-TiO₂ solar absorber was prepared in this study. • A good photo-thermal conversion property was verified by experiments. • A novel system with the solar absorber for evaporation enhancement was designed. • The enhancement was investigated by experiments and theoretical calculations. Solar steam generation, a typical solar energy utilization way, has wide applications and attracts many researches, such as the enhancement achieving by numerous nanomaterials and porous membranes. However, some issues need to be solved (e.g., blockage of pore structures and poisoning of film nanoparticles (NPs)), which are critical for developing sustained and efficient evaporation processes. In this sense, we developed herein a novel evaporation method involving a thin water layer and a highly efficient solar absorber for enhanced steam generation. This technology prevented pore blockage and poisoning of NPs by employing a dense surface structure and continuous water flow. A C-Au-TiO₂ solar absorber prepared by a sol-gel method with a superior photo-thermal conversion capacity, even for lights with large angles of incidence was the key to enhance the solar steam generation process. By experiments and theoretical calculations for solar evaporation, the steam generation performance and heat change process were investigated. It was found that improving the light absorption of the solar absorber and reducing the thermal loss were effective methods to enhance evaporation rate and efficiency, while reducing the water height could cut down the time needed to reach stable stage. And the C-Au-TiO₂ solar absorber achieved a significantly enhanced solar steam generation, which may pave the way for developing new highly efficient solar steam generation paths.