Fe(III)-grafted K-doped g-C ₃N ₄ /rGO composite photocatalyst with efficient activity towards the degradation of organic pollutants ^§

Abstract: The quick recombination of charge carriers and the low oxidizing ability of VB holes of g-C ₃N ₄ limits its practical application. Herein, we have synthesized a visible-light sensitive Fe(III)-grafted K-doped g-C ₃N ₄/ rGO heterostructure photocatalyst to tackle the above problem so as to achieve enhanced photocatalytic activity. The prepared samples were characterized by standard analytical techniques such as XRD, FT-IR, EPR, SEM, TEM, DRS and PL spectroscopy. EPR analysis reveals that the grafted iron exists in +3 oxidation state in the composite material. As compared to pristine g-C ₃N ₄, surface grafted nanocomposite photocatalyst exhibits excellent photocatalytic performance for the degradation of Rhodamine B (RhB), Methylene Blue (MB) and Methyl Orange (MO) under visible light irradiation. The enhanced activity could be attributed to the creation of defect levels in the band gap, shift of absorption band towards the visible region and intimate interfacial interactions between graphene and g-C ₃N ₄, effectively promoting separation of photoinduced charge carriers. The idea to tune the bandgap of graphitic carbon nitride by introducing alkali metal along with its composite formation with graphene could present a new concept to effectively steer the photocatalytic activity. Graphical Abstract: SYNOPSIS New visible light sensitive Fe(III)-grafted K-doped g-C ₃N ₄ reduced graphene oxide composite was prepared and its photocatalytic activity under visible light was evaluated by studying the degradation of RhB, MB and MO in aqueous suspension.[Figure not available: see fulltext.].