H-2 EVOLUTION REACTIVITY OF CARBON-BEARING NI(II) FERRITE (CBNF)

Two-step water-splitting with a carbon-bearing Ni(II) ferrite (CBNF) a t 300 degrees C has been studied. The chemical analysis of the solid p hase showed that the CBNF was gradually oxidized during repeated water splitting, but the evolved H-2 amount is 1.5-2 times larger than that expected from the oxidation of the CBNF. Following two types of hydro gen evolution reactions are considered to be participated: Type I is t he water splitting by the activated form of CIO layer(alpha(n)), where the activated form changes to the original form (beta(n)), Type II is hydrogen evolution by the oxidation of CIO layer, where the original CIO layer form(beta(n)) changes to an oxidized form (beta(n+1)) The am ount of released oxygen was about 40-80% of the amount estimated from the amount of hydrogen gas evolved by the Type I reaction. Thus, the s toichiometry of the above two steps has been demonstrated.