Preparation of RGO-MIL-68(Fe) composites by a simple self-assembly strategy for photocatalytic reduction of Cr(Ⅵ)

Novel photocatalysts reduced graphene oxide (RGO)-MIL-68(Fe) were synthesized via an electrostatically derived self-assembly of MIL-68(Fe) with graphene, followed by solvothermal approach. The as-prepared RGO-MIL-68(Fe) composites were characterized by XRD, FESEM and UV-vis diffuse reflectance spectra (UV-vis DRS). The photocatalytic activity for reduction of Cr(Ⅵ) over RGO-MIL-68(Fe) composites were investigated under visible light irradiations using ammonium oxalate ((NH₄)₂C₂O₄) as a sac-rificial agent. The results show that the reduction of Cr(Ⅵ) over MIL-68(Fe) can be significantly increased by loading RGO. An optimum activity is achieved over 1wt%RGO-MIL-68(Fe) composite, giving a corresponding Cr(Ⅵ) reduction ratio of 81% after 60 min under visible light irradiation. Combining with photoelectrochemical analyses, it can be revealed that the introduction of RGO will minimize the recombination of photogenerated electron-hole pairs.