Since the CO2 •-in reaction 1 results from mediated C2O4 2-oxidation at an anode, we refer to this method as "oxidative reduction" or, equivalently, "reduction by oxidation." Cyclic voltammetry is first employed to examine the feasibility of the oxidative reduction method. Then, we demonstrate that efficient conversion of Ar-X (X = Br, Cl) to Ar-H (i.e., reductive hydrodehalogenation) in controlled-potential electrolysis is achieved in < 4 h at very moderate potentials (~ 0 V vs Fc/Fc + ).