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

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 ben-efits, 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.