Hydrogen sulfide dissociation in nanosecond dielectric barrier discharge

Hydrogen sulfide (H$_2$S) is a byproduct of oil refinement, and it comprises a large portion of natural gas deposits. The minimum dissociation energy of hydrogen sulfide is only 0.2 eV/molec, and it is very important commercially. The process of hydrogen sulfide dissociation was investigated in nanosecond dielectric barrier discharge (ns-DBD). Experiments on dissociation of H$_2$S in ns-DBD allows for effective separation of ion-molecular and thermal effects, which is necessary for understanding the potential and limitations of plasma dissociation of hydrogen sulfide. The study was performed in a reactor, in which there is no contact between any metal parts (including electrodes) and H$_2$S. It is well known that many common metals and alloys either react or catalyze H$_2$S dissociation (especially at elevated temperature); our reactor design eliminates this problem. This study was performed in a moderately low pressure reactor (50 - 200 Torr) with 100\% pure hydrogen sulfide. The minimum dissociation energy cost was found to be less than 5 eV/molec at room temperature, which is significantly better than results obtained in earlier studies using discharges with high $E/n$ and low gas temperature.