ABSTRACT
The Hybrid Sulfur (HyS) cycle (Figure 18.1) is one of the simplest thermochemical watersplitting processes, comprising only two reactions with all reactants and products in the ¦uid state. Known also as the Westinghouse Sulfur or Ispra Mark 11 cycle, it entails coupled reactions that cycle sulfur between its +4 (sulŒte) and +6 (sulfate) oxidation states. One of the two reactions is thermochemical (high-temperature, endothermic) while the other is electrochemical, making it a hybrid thermochemical cycle.
