Multi-networked nanofibrous aerogel supported by heterojunction photocatalysts with excellent dispersion and stability for photocatalysis

Abstract

Suitable carriers enhance the dispersion and stability of powder photocatalysts and further expand their applications. Nevertheless, the preparation of such active supports presents significant challenges owing to the complicated synthetic conditions and high cost entailed. Therefore, novel bi-component and multi-networked nanofibrous aerogels (BMFAs) were successfully designed and fabricated using a maneuverable and economical approach. Specifically, BMFAs became more stable and active owing to the H-bond interactions between natural cellulose and aminated electrospun polyacrylonitrile (PAN) nanofibers. The multi-network remarkably assisted BMFAs as an optimal template for the in situ growth of NH₂-MIL-88B(Fe) (NM88) and loading of g-C₃N₄ (g-CN), which were anchored in the multi-network to construct a heterojunction owing to the volume shrinkage of BMFAs. Thus, the recyclable 3D g-CN@NM88/BMFA nanocomposites with low-density, super-hydrophilicity and excellent stability were successfully prepared and expectedly exhibited excellent photocatalytic performances towards Cr(VI) reduction (99%) within 20 min over a broad pH range, which is superior to that exhibited by many reported materials. Besides, g-CN@NM88/BMFA nanocomposites also presented good activities for hydrogen evolution and SMZ degradation and antibacterial properties. The mechanisms behind many excellent solar-driven photocatalytic properties were primarily attributed to the photo-induced electron transfer and multiple active species interaction processes. Moreover, the negligible Fe leaching and multi-cycles of photocatalysis processes indicated the superior stability of g-CN@NM88/BMFA nanocomposites. Hence, the ordered array of the self-assembled nano-heterojunction photocatalysts, which exhibited favorable stability and excellent dispersion, could promote their wide application in both environmental remediation and energy transfer.