Efficient capture and conversion of HS into H and sulfur in guanidinium ionic liquid-NaOH aqueous solution.

Electrochemistry allows for the simultaneous conversion of hydrogen sulfide (HS) to hydrogen (H) and sulfur, achieving atomic economy, and is a sustainable and cost-effective method. At the same time, an electrolyte with high conductivity and HS absorption that can effectively capture HS in an electrochemical process is essential. An ionic liquid electrolyte system for the absorption and electrolysis of HS was constructed using the guanidine salt ionic liquid with amine-based functional groups as the carrier electrolyte, water as the solvent, and NaOH as the HS absorber. The prepared electrolyte ([TMG][IM]-AE-30) showed a strong absorption of HS with an equilibrium solubility of 100.82 g L. Under constant potential electrolysis at 1.0 V . RHE, the maximum hydrogen production rate reaches 2919.97 μmol h and the Faraday efficiency reaches 99%, and the anodic product is α-sulfur with a production of 0.881 g after electrolysis for 8 h; the current density and hydrogen production rate are still higher than those of the AE systems after three cycles. Overall, the system has good hydrogen sulfide absorption and electrolysis performances, and [TMG][IM] can effectively improve the HS absorption and electrolysis efficiencies.