Stabilizing Iron Oxide Used in Cycles of Reduction and Oxidation for Hydrogen Production
Stabilizing Iron Oxide Used in Cycles of Reduction and Oxidation for Hydrogen Production
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DOI：
10.1021/ef100199f
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发表时间：
2010-07-01
期刊：
影响因子：
5.3
通讯作者：
Dennis, J. S.
中科院分区：
文献类型：
--
作者：
Bohn, C. D.;Cleeton, J. P.;Dennis, J. S.
改性氧化铁 Fe2O3 用于通过重复的还原和氧化循环来生产纯 H-2。在 1123 K 的填充床上用 (i) CO + N-2 或 (ii) H-2 + N-2 进行还原；再氧化用(iii)蒸汽+N-2进行，并且在一些情况下另外用(iv)空气+N-2进行。如果 Fe2O3 仅还原为 FeO，则可在重复循环中观察到稳定的 H-2 产率。如果 Fe2O3 完全还原为 Fe，则观察到 H-2 产率随着循环次数的增加而降低。通过用 Al、Cr、Mg 和 Si 进行湿浸渍制备改性 Fe2O3 样品，金属添加剂的负载量分别为 1、10 和 30 mol%。当 Fe2O3 还原为 Fe 时，添加金属添加剂可以改善甚至有时稳定产生的 H-2 量。金属添加剂（i）形成比所涉及的铁物质（即 Fe2O3、Fe3O4、FeO 和 Fe）熔点更高的中间体，并且（ii）形成在还原或氧化过程中分解以释放活性铁的中间体，增加了 H-2 的产生量。含 30 mol% Cr 的样品在 10 个循环中获得了稳定的 H-2 产率；如果在空气中进行额外的氧化以将 FeO 中心点 Al2O3 氧化为 Fe2O3 和 Al2O3，则具有 10 mol% Al 的样品可以获得超过 10 个循环的稳定 H-2 产率。
Modified iron oxide, Fe2O3, was used to produce pure H-2 using repeated cycles of reduction and oxidation. Reduction was performed in a packed bed at 1123 K with either (i) CO + N-2 or (ii) H-2 + N-2; reoxidation was performed with (iii) steam + N-2 and additionally with (iv) air + N-2 in some cases. Stable yields of H-2 over repeated cycles were observed if Fe2O3 was reduced only to FeO. Decreasing yields of H-2 with an increasing cycle number were observed if Fe2O3 was fully reduced to Fe. Samples of modified Fe2O3 were prepared via wet impregnation with Al, Cr, Mg, and Si to give loadings of 1, 10, and 30 mol % of the metal additive. The addition of a metal additive was shown to improve and sometimes stabilize the quantity of H-2 produced when Fe2O3 was reduced to Fe. Metal additives which (i) formed an intermediate with a higher melting temperature than the iron species involved, i.e., Fe2O3, Fe3O4, FeO, and Fe, and (ii) formed an intermediate that decomposed either during reduction or oxidation to release reactive iron, increased the quantity of H-2 produced. Stable H-2 yields over 10 cycles were obtained for the sample with 30 mol % Cr; stable H-2 yields over 10 cycles were obtained for the sample with 10 mol % Al if additional oxidation in air was performed to oxidize FeO center dot Al2O3 to Fe2O3 and Al2O3.