Hydrogen (H2) Recovery From Hydrogen Sulfide (H2S): Current Technologies, Challenges, and Future Outlook.

Hydrogen sulfide (H2S) can be transformed into hydrogen (H2) through several chemical and catalytic processes, offering a promising route for both waste treatment and clean H2 production. This colorless, flammable, and toxic gas is found abundantly in swamps, volcanoes, hot springs, sewages, other natural gas fields, and even in refineries and during some industrial processes. A very low concentration of H2S could cause adverse health impacts and even fatality. Therefore, removal of H2S is necessary. Moreover, decomposition of H2S produces H2 which is being considered as one of the most promising sustainable clean energy solutions. The by-product, sulfur, holds additional value through its diverse industrial applications and contribute to the circular economy. Numerous techniques, including thermal, thermo-catalytic, photocatalytic and electrocatalytic approaches, are employed for H2S decomposition. This review provides a comprehensive discussion on recent progress on H2S splitting via different methods, including thermocatalysis, photocatalysis, electrocatalysis and plasma-assisted decomposition to guide innovations in this highly promising yet unexplored areas. Moreover, energy requirement, economic viability and current market status are also explored. Finally, key challenges and future perspectives of this highly promising research area are discussed, directing great potential for future explorations.