Polyimide aerogels crosslinked with MWCNT for enhanced visible-light photocatalytic activity

Polyimide (PI) aerogel cross-liked through multi-walled carbon nanotube (MWCNT) has been successfully synthesized by gelation of chemically imidized polyimide in N-methylpyrrolidinone (NMP) solution, followed by ethanol supercritical drying. The as-prepared PI(MWCNT) aerogel photocatalyst with 1 wt% MWCNT content exhibited excellent photocatalytic activity for oxytetracycline (OTC) degradation with a rate constant of 0.144 min−1, which is 20.6 and 3.3 times as many as that of PI powder and pure PI aerogel, respectively. Characterizations by a series of techniques certified that the enhanced photocatalytic activity of PI(MWCNT)-1% aerogel photocatalyst originated from not only the large specific area and modified band gap, but also the enhanced charge transfer effect because MWCNT can interact with PI through the π-π stacking interaction. The photo-induced electrons can be captured and rapidly transferred by MWCNT, efficiently enhancing the separation efficiency of photo-induced electron-holes.