(511g) Cobalt-Iron Spinel Oxides And Their Application For Solar Thermochemical Hydrogen Production

Spinel ferrites, mixed metal oxides formed by substitution of iron in Fe₃O₄ by other metals, are capable of splitting water at relatively low temperatures.

We have investigated the role of specific surface area of Co_xFe_3-xO₄, where x ranges from 0.25 to 1.0, on the amount of oxygen evolved per mole of ferrite, and its subsequent reactivity with steam to generate hydrogen gas. Our results indicate that, by reducing particle size and thus increasing specific surface area, the amount of hydrogen generated per mole of ferrite can be significantly increased. XPS and EDS were utilized as a means to analyze the reduced samples, and confirm that oxygen atoms are evolved primarily from the surface, rather than the bulk lattice.