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.