Integrating stable radical hydrogen-bonded organic frameworks with silver nanoparticles for highly efficient solar-driven water evaporation
摘要
Global freshwater scarcity is a serious environmental issue facing the world today. One of the promising solutions is to employ solar energy to evaporate seawater and collect freshwater. This approach, however, requires the development of materials with excellent photothermal conversion performance. Herein, we report a post-modification method to effectively oxidize hydrogen-bonded organic frameworks (HOFs) to open-shell radical state, and simultaneously load silver nanoparticles on HOFs, obtaining Ag@oxidized HOFs (Ag@oxHOFs). Compared with pristine HOFs, Ag@oxHOFs present stable radical states in air and water, and display a broad absorption within the solar spectrum and excellent photothermal conversion ability. In particular, Ag@oxPFC-1 (PFC refers to porous materials from FJIRSM, CAS), under 808 nm light irradiation, can surge to 198.1 °C with the photothermal conversion efficiency as high as 69.8%. The sample is further loaded onto the airlaid paper as a proof-of-concept device to simulate solar-driven water evaporation. As a result, the water evaporation rate reaches 1.445 kg m−2 h−1, with 93.6% efficiency. This work showcases a post-synthesis method that can trigger the radical state of HOFs and in situ generate silver nanoparticles, providing pivotal insights into the preparation of high-performance photothermal materials.