Recovery of Hydrogen and Sulfur by Electrolysis of Ionized H₂S in an Amine-Containing Organic Electrolyte with Highly Temperature-Dependent Sulfur Solubility

Abundant hydrogen sulfide (H₂S) from nature and industry has been considered a harmful substance. However, it is a potential resource if valuable H₂ and elemental sulfur can be recovered from H₂S. Herein, a new organic electrolyte system was constructed for H₂S direct electrolysis using tetraethylene glycol dimethyl ether as the solvent, ionic liquid [C₃OHmim]­BF₄ as the supporting electrolyte, and monoethanolamine (MEA) as the absorbent for H₂S. The as-prepared electrolyte was found useful as highly temperature-dependent on the sulfur solubility electrolyte with catalytic effects of sorbent MEA, conducive to solving passivation problems caused by sulfur adhesion in direct electrolysis of H₂S and sulfur recovery in indirect electrolysis. Moreover, the as-obtained organic electrolyte showed certain stability with Faraday efficiency of H₂ generated after three heating–electrolysis–cooling cycles, reaching 89%. In summary, the as-obtained electrolyte looks promising for efficient and continuous electrolysis of H₂S.