An electrochemical claus process for sulfur recovery

Electrochemical oxidation of H{sub 2}S to give sulfur and water was achieved at 900{degrees}C using fuel cells possessing the general configuration where anode electrocatalysts experimentally investigated for promoting the subject oxidation reaction included WS{sub 2} and the thiospinels CuNi{sub 2}S{sub 4}, CuCo{sub 2}S{sub 4}, CuFe{sub 2}S{sub 4}, and NiFe{sub 2}S{sub 4}. The predominant oxidizable electroactive species present in the fuel cell anode compartment was suggested to be hydrogen originating from the initial thermal dissociation of H{sub 2}S (H{sub 2}S {r reversible} H{sub 2} + 1/2 S{sub 2}) at fuel cell operating temperatures. Rapid anode kinetics were found for the anodic reaction with the empirical trend for exchange currents (i{sub o}) per geometric area being found to be NiFe{sub 2}S{sub 4}{gt}WS{sub 2}{gt}CuCo{sub 2}S{sub 4}{gt}CuFe{sub 2}S{sub 4}{approx equal}NiCo{sub 2}S{sub 4}{gt}CuNi{sub 2}S{sub 4}.