Hierarchical porous metallic glass with strong broadband absorption and photothermal conversion performance for solar steam generation

The development of a strong light absorption absorber with a facile preparation process are crucial for some photothermal conversion applications, such as solar steam generation, photothermal catalysis and detectors. Here, a hierarchical structure based on microporous surface equipped with nanoporous layer is ingeniously designed and fabricated benefiting from the unique thermoplastic forming ability of metallic glasses by using the soluble clusters as template in less than 30 s. The presence of hierarchical porous structures induces multiple reflection of light and excites the plasmonic behavior of surface, achieving over 90% light absorption in the 380–20 µm wavelength range and the broad light incident angle from 0° to 70°, resulting in a remarkable photothermal conversion performance. Compared to conventional and existing absorber, the innovatively designed and fabricated metallic surface offers outstanding advantages in terms of light absorption range, heating rate and maximum temperature rise. Afterwards, the hierarchical porous structures for solar steam generation shows an evaporation efficiency of up to 94.2% and evaporation rate of 1.72 kg m−2 h−1 at 1 kW m−2. The design of unprecedented structure on metallic glass opens up a new strategy for solar energy harvesting, water treatment and other related fields.