Electrochemical Sulfion Valorization Using Biphasic Electrolyte and Transition Metal Selenization Simultaneously Enabled by Ionic Liquid

Preventing electrode passivation is a critical challenge in direct electrochemical desulfurization of aqueous solution systems. Here, a hydrophobic imidazole ionic liquid [HMIM]PF₆ was introduced into the electrode and electrolyte for constructing a new sulfide oxidation reaction (SOR) system. [HMIM]PF₆ was utilized as both a phosphating agent and a dopant in the synthesis of catalysts. It promoted the attachment of precursors to nickel foam, which was then fully selenized to form P-, F-, and N-doped Co_0.85Se/NF. At a potential of only 0.29 V, a current density of 100 mA cm^-2 was achieved, with no degradation in catalytic performance observed after 600 h of stability testing. [HMIM]PF₆ incorporated biphasic can prevent sulfur adhesion to the electrodes, because [HMIM]PF₆ accelerates the extraction of SOR products from the electrode phase. The SOR products were identified as S₈ and Na₂SO₃, which were successfully extracted using a novel green condensation reflux method, ensuring the recyclability of [HMIM]PF₆. This work offers a novel approach to improve the electrochemical performance of the SOR.