Low-temperature catalytic decomposition of hydrogen sulfide on metal catalysts under layer of solvent

Abstract

When hydrogen sulfide decomposition {2 H2S ↔ 2 H2 + S2(gas)} is carried out in the flow regime at room temperature on metal catalysts placed in a liquid capable of dissolving H2S and sulfur, the reaction equilibrium can be significantly (up to 100%) shifted to the right yielding the desired product – hydrogen. The process efficiency was demonstrated using aqueous solutions of monoethanolamine (MEA), sodium carbonate, which is widely used in industry for H2S absorption from tail gases, and aqueous hydrazine as examples. IR and Raman spectroscopy data demonstrated that sulfur obtained in the solutions is in the form of diatomic molecules. DFT calculations showed that diatomic sulfur forms weakly bound coordinative complexes with solvent molecules. Some problems related to sulfur accumulation and recovery from the solvents are discussed.