Electrospun, flexible and reusable nanofiber mat of graphitic carbon nitride: Photocatalytic reduction of hexavalent chromium

Nanofiber mat of graphitic carbon nitride (g-C3N4) was fabricated from g-C3N4/polyvinylidene fluoride (PVDF) composite using an electrospinning technique. The mat was characterized with SEM, AFM, XRD, FTIR and photoluminescence (PL) spectroscopy. This nanofiber mat is flexible and can be folded or rolled without losing any structural integrity. The nanofiber mat also demonstrates self-cleaning properties in aqueous medium as demonstrated with two dyes, methylene blue and rhodamine B. Hexavalent chromium was successfully reduced by the nanofiber mat of g-C3N4 under visible light. Although the rate of reduction of Cr(VI) was very slow in presence of nanofiber mat of g-C3N4 alone, it was enhanced significantly in presence of trace amounts (0.3%) formic acid. Formic acid played the dual role of hole scavenging agent of g-C3N4 to make the photogenerated electrons more available to the reaction and generating H-2 and CO in the system that can also directly reduce Cr(VI) onto Cr(III). The nanofiber mat demonstrated excellent cyclability for photocatalytic reduction of Cr(VI) and self-cleaning properties in presence of visible light. (C) 2020 Elsevier Inc. All rights reserved.