One-pot sustainable preparation of sunlight active ZnS@graphene nano-composites using a Zn containing surface active ionic liquid

Herein we report a facile and sustainable method for the preparation of ZnS@graphene nano-composites (NCs). An appreciable amount of graphene is obtained by liquid-phase exfoliation using a zinc-containing surface active ionic liquid (SAIL). It is followed by in situ preparation of ZnS quantum dot (QD) decorated graphene sheets at room temperature for the first time. The employed method is distinct from all previous reports, as we have employed graphene instead of graphene oxide (GO) or reduced graphene oxide (rGO) and used relatively fewer chemicals. Further, a SAIL is employed as a precursor of Zn(2+) as well as a template for the preparation of ZnS QDs onto graphene. The prepared ZnS@graphene NCs show enhanced photocatalytic performance for the degradation of Rhodamine B dye under sunlight and ciprofloxacin antibiotic under visible light as compared to bare ZnS QDs. The better photocatalytic activity of the NCs under visible light compared to that reported in the literature along with the ease of preparation is advantageous for scaling-up the process.