Studies on redox H2–CO2 cycle on CoCrxFe2−xO4

Completely reduced CoCrxFe2−xO4 can be used to decompose CO2. It was found that for pure CoFe2O4 there is no FeO formation in the first step while there is formation in the second step. For CoCr0.08Fe2−0.08O4, there is no FeO formed in all the oxidation process, because of effect of Cr3+. Pure CoFe2O4 was destroyed at the first reaction cycle of H2 reduction and CO2 oxidation, while doped Cr3+ spinel CoCr0.08Fe1.92O4 showed good stability. The results from H2-TG, CO2-TG and XRD show that the addition of Cr3+ to CoFe2O4 can inhibit the increasing of crystallite size and the sintering of alloy. Most importantly, the CoCr0.08Fe1.92O4 can be used to decompose CO2 repeatedly, implying that it is a potential catalyst for dealing with the CO2 as a ‘green house effect’ gas.

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