Studies on redox H_2-CO_2 cycle on CoCr_xFe_(2-x)O_4

摘要

Completely reduced CoCr_xFe_(2-x)O_4can be used to decompose CO_2. It was found that for pure CoFe_2O_4 there is no FeO formation in the first step while there is formation in the second step. For CoCr_(0.08)Fe_(2-0.08)O_4, there is no FeO formed in all the oxidation process, because of effect of Cr~(3+). Pure CoFe_2O_4 was destroyed at the first reaction cycle of H_2 reduction and CO_2 oxidation, while doped Cr3~(3+) spinel CoCr_(0.08)Fe_(1.92)O_4, showed good stability. The results from H_2-TG, CO_2-TG and XRD show that the addition of Cr~(3+) to CoFe_2O_4 can inhibit the increasing of crystallite size and the sintering of alloy. Most importantly, the CoCr_(0.08)Fe_(1.92)O_4 can be used to decompose CO_2 repeatedly, implying that it is a potential catalyst for dealing with the CO_2 as a 'green house effect' gas.