One-Step Low-Temperature Reduction of Sulfur Dioxide to Elemental Sulfur by Plasma-Enhanced Catalysis

The low-temperature conversion of sulfur dioxide (SO2) to elemental sulfur in a single catalytic step remains elusive. Here we report a one-step, low-temperature, plasma-enhanced catalytic process for direct SO2 reduction to elemental sulfur in a dielectric barrier discharge (DBD) packed bed reactor. Coupling nonthermal plasma with supported iron sulfide catalyst dramatically promotes SO2 reduction at low temperatures, enhancing SO2 conversion by 200% and 100% using H-2 and CH4, respectively. Interestingly, under plasma conditions, the supported zinc sulfide catalyst showed high SO(2 )reduction activity, although it is thermally inactive even at higher temperatures. The possible origin of these synergetic effects as well as plasma influence on SO2 adsorption are discussed.