Folic acid and CuS conjugated graphene oxide: An efficient photocatalyst for explicit degradation of toxic dyes

Abstract

A robust, ternary photocatalyst, GO-FA-CuS was prepared by covalent conjugation of folic acid (FA) to graphene oxide (GO) nanosheets and subsequent deposition of CuS nanoflowers. The photocatalytic efficiency of GO-FA-CuS was evaluated by degradation rate of industrially versatile used dyes, rhodamine B, methylene blue, methyl orange and alizarin red s by irradiating to near-infrared (NIR) laser. The complete degradation of all four dyes was attained by excellent photocatalytic activity of GO-FA-CuS. Incorporation of GO, FA and CuS in GO-FA-CuS, significantly improved their individual photocatalytic activity with several fold. In GO-FA-CuS, GO and CuS were performed as a collector of holes and captor of electrons, respectively. The blending of FA with GO and CuS, tuned the GO-FA-CuS as an efficient photocatalyst and opened a new era of FA in photocatalysis, apart from its classical application in biomedical field. The hierarchical structured, GO-FA-CuS emerged with important benefits, viz., efficient suppression of recombination of photogenerated electrons and holes, higher adsorption of dye molecules and elevated harvesting of NIR light. The photocatalytic activity of GO-FA-CuS in degradation of rhodamine B was higher under exposure to NIR laser rather than UV, visible and sunlight. The facile degradation of rhodamine B found in NIR laser was influenced by photothermal effect. GO-FA-CuS possessed the negative surface charge, because of that, its photocatalytic activity was higher in degradation of cationic dyes, rhodamine B and methylene blue compared to anionic dyes, methyl orange and alizarin red s. The GO-FA-CuS demonstrated significant stability and easy recycling ability for repeated use.