Copper nanoparticles embedded flexible graphene aerogel for effective capture of iodine vapor

Development of highly efficient and low-cost adsorbents for radioactive iodine vapor is significant but still challenged now. In this work, we reported a novel graphene aerogel (GA-Cu-ED) decorated by zero-valence copper and nitrogen active sites, prepared via a two-step route of hydrothermal reaction and freeze-drying processes. The combination of X-ray photoelectron spectroscopy (XPS) valence imaging and high-resolution transmission electron microscope (TEM) confirms the formation of Cu⁰ and its uniform distribution. Besides, the good elasticity and ultra-low density of this aerogel were proved. Adsorption experiments indicate that GA-Cu-ED has a high adsorption capacity of 3.76 g/g for gaseous iodine and short adsorption equilibrium time of 90 min. Even after three cycles, this aerogel still shows an almost unchanged adsorption capacity of 3.74 g/g. Meanwhile, this aerogel can be long-term stored under air atmosphere with only slight loss in adsorption performance. In addition, the captured iodine molecules can be tightly bound in this aerogel even after being exposed in air for three days. Mechanism analysis indicates the I-benzene conjugation, I–N charge transfer, and I₂–Cu⁰ chemisorption contribute together to the capture of gaseous iodine. Therefore, our work provides a highly efficient and reliable adsorbent for radioactive iodine vapor, which may be worthy in large-scale application in future.