Low-cost Preparation of Graphene Papers from Chemical Reduction with FeI₂/Ni²⁺ for Conductivity and Catalytic Property

A novel method to produce reductive graphene oxide (RGO) with FeI 2 /Ni 2+ applied as reductive agent was reported. This method provides a cheap, effective and environmentally friendly route for the large-scale production of RGO without losing its high conductivity and catalytic activity. An extremely high conductivity of 30231 S/m was obtained affer the optimized FeI 2 /Ni(NO 3 ) 2 solution treatment. The enhancement of bulk conductivity was clue to the promotion of the nucleophilic substitution reaction induced by Fe 2+ (a strong Lewis acid). Ni 2+ was introduced to optimize the reductive process by reducing the concentration of hydrogen ions, which would inhibit the hydrolysis of Fe 2+ . Furthermore, a high cathodic peak current density was observed when applying the free-standing RGO paper as counter electrode in I -/I 3-electrolyte system, indicating the high catalytic performance of the RGO paper and providing electron transporting pathway. These outstanding features exhibit a promising prospect of application in solar cells.