Fe_(3+δ)O_4的制备及CO_2完全分解成碳的研究

Preparation of Fe_(3+δ)O_4 and Their Complete Decomposition of CO_2 to Carbon

在低温(358K)下用空气氧化Fe(OH)_2悬浮液制备了阳离子缺位的磁铁矿(Fe_(3-δ)O_4,0.2>δ>0.在563K下用H_2还原活化Fe_(3-δ)O_4制得了阳离子过量的磁铁矿(Fe_(3+δ)O_4,0.2>δ>0),并考查了不同温度和气氛下该磁铁矿的稳定性.研究了CO_2在Fe_(3+δ)O_4上563K下的分解活性,发现CO_2几乎100%地还原成碳,氧被以O^(2-)离子形式转移给了Fe_(3+δ)O_4,而变成化学计量的Fe_3O_4.磁铁矿阳离子过量程度越大,分解CO_2的活性越高,分解的量也越大.

The Cation-deficient magnetite (Fe3-δO4, 0.2>δ>0) was synthesized by the air oxidation of Fe(OH)2 suspensions at 358K. The cation-excess magnetite (Fe3+δO4, 0.2>δ>0) was obtained by flowing H2 gas through cation-deficient magnetite at 563K, the stability of the magnetite is examined at various temperpatures and under atomspheres. Reactivity of Fe3+δO4 (0.2 >δ>0) to reduce CO2 gas into carbon was studied at 358K. The results confirm that CO2 was nearly 100% decomposed into carbon, the oxygen in the CO2 is transferred, in the form of O2-, to the cation excess magnetite. The bigger the cation-excess degree of magnetite, the higher the decomposition activation of CO2 is, the more the amount of decomposited CO2.