The reaction thermodynamics of hydrogen sulfide decomposition into hydrogen and diatomic sulfur

To verify a hypothesis about the electronic state of diatomic gaseous sulfur formed during the low-temperature catalytic decomposition of hydrogen sulfide, we carried out some experiments to examine elemental sulfur dissociation. As shown, after heating at similar to 1000 K, elemental sulfur sealed in quartz ampoules with metal catalysts followed by quenching at room temperature did not produce any visible changes on solid sulfur. However, conversion of solid sulfur into gaseous diatomic sulfur can be realized via intermediate interaction of melted sulfur with hydrogen in the presence of Pt followed by decomposition of H2S formed on the surface of the metal catalyst at room temperature. It is suggested that the conversion of the singlet sulfur atoms into the ground triplet state becomes feasible only on the surface of metal catalysts resulted from the dissociation of hydrogen sulfide into adsorbed atomic species.