Facile preparation of flexible polyacrylonitrile/BiOCl/BiOI nanofibers via SILAR method for effective floating photocatalysis

Flexible and floating photocatalysts have unique advantages in water pollution treatment due to their light-harvesting and recycle performance. Here, a facile successive ionic layer adsorption and reaction (SILAR) method was used to layer by layer grow BiOCl/BiOI heterojunctions on self-supporting electrospun polyacrylonitrile (PAN) nanofiber mats at room temperature. This method enables tunable good interface contact of the heterojunctions while makes the composites maintain flexibility and floatable properties. The PAN/BiOCl/BiOI nanofibers show much better photocatalytic activity than the PAN/BiOCl and PAN/BiOI nanofibers. For removal of Rhodamine-B and Bisphenol-A, the degradation rates of PAN/BiOCl/BiOI nanofibers were about 1.68 and 1.41 times higher than PAN/BiOCl nanofibers and were 2.27 and 2.01 times higher than PAN/BiOI nanofibers, respectively. The high photocatalytic performance could be attributed to the effective interfacial charge separation of BiOCl/BiOI heterojunctions, confirmed by the enhanced photocurrent densities, and significantly decreased photoluminescence intensity. The photocatalytic activity of these composite nanofibers could be further improved by adjusting the contents of BiOCl and BiOI in the heterojunction due to the excellent controllability of the SILAR method. Furthermore, the PAN/BiOCl/BiOI nanofibers can float easily and directly reused due to their flexible and self-supporting fiber mats structures. It was expected that the PAN/BiOCl/BiOI nanofibers with high photocatalytic activity and easily separable properties would be useful for industrial wastewater remediation.