Catalytic Hydrogen Evolution from H₂S Cracking over Cr_xZnS Catalyst in a Cylindrical Single-Layered Dielectric...

The use of non-thermal plasma technology in producing green fuels is a much-appreciated environmentally friendly approach. In this study, an Al₂O₃-supported Cr_xZnS semiconductor catalyst was tested for hydrogen evolution from hydrogen sulfide (H₂S) gas by using a single-layered dielectric barrier discharge (DBD) system. The Al₂O₃-supported Cr_xZnS catalyst (x = 0.20, 0.25, and 0.30) was produced by using a co-impregnation method and characterized for its structural and photocatalytic characteristics. The discharge column of the DBD system was filled with this catalyst and fed with hydrogen sulfide and argon gas. The DBD plasma was sustained with a fixed AC source of 10 kV where plasma produced species and UV radiations activated the catalyst to break H₂S molecules under ambient conditions. The catalyst (hexagonal-cubic-sphalerite structure) showed an inverse relationship between the band gap and the dopant concentration. The hydrogen evolution decreased with an increase in dopant concentration in the nanocomposite. The Cr_0.20ZnS catalyst showed excellent photocatalytic activity under the DBD exposure by delivering 100% conversion efficiency of H₂S into hydrogen. The conversion decreased to 96% and 90% in case of Cr_0.25ZnS and Cr_0.30ZnS, respectively.