Zinc–zinc oxide cycle

For chemical reactions, the zinc–zinc oxide cycle or Zn–ZnO cycle is a two step thermochemical cycle based on zinc and zinc oxide for hydrogen production with a typical efficiency around 40%. The thermochemical two-step water splitting process uses redox systems: Dissociation: ZnO → Zn + 1/2 O2 Hydrolysis: Zn + H2O → ZnO + H2 For the first endothermic step concentrating solar power is used in which zinc oxide is thermally dissociated at into zinc and oxygen. In the second non-solar exothermic step zinc reacts at with water and produces hydrogen and zinc oxide. The temperature level is realized by using a solar power tower and a set of heliostats to collect the solar thermal energy.