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Hexavalent chromium Cr(VI) is a highly toxic groundwater contaminant. In this study, we demonstrate a selective electrochemical process tailored for removal of Cr(VI) using a hybrid MOF@rGO nanomaterial synthesized by in situ growth of a nanocrystalline, mixed ligand octahedral metal–organic framework with cobalt metal centers, [Co₂(btec)(bipy)(DMF)₂]_n (Co-MOF), on the surface of reduced graphene oxide (rGO). The rGO provides the electric conductivity necessary for an electrode, while the Co-MOF endows highly selective adsorption sites for CrO₄^2–. When used as an anode in the treatment cycles, the MOF@rGO electrode exhibits strong selectivity for adsorption of CrO₄^2– over competing anions including Cl^–, SO₄^2–, and As(III) and achieves charge efficiency (CE) >100% due to the strong physisorption of CrO₄^2– by Co-MOF; both electro- and physisorption capacities are regenerated with the reversal of …