Advances in New and Renewable Energy >
Oxygen Release Mechanisms of Cu-Based Oxygen Carriers Based on Density Functional Theory Calculations
Received date: 2016-06-08
Revised date: 2016-08-17
Online published: 2016-10-28
Chemical-looping with oxygen uncoupling (CLOU) is a new combustion method based on chemical-looping combustion technology, which allows intrinsic separation of pure CO2 from hydrocarbon combustion. The key point of CLOU is finding an ideal oxygen carrier that has good oxygen adsorption and releasing characters. The reactivity of oxygen carriers in macro-level is determined by the mechanism of microscopic lattice oxygen transportation, but few attentions have been paid on the subject currently. This article used density functional theory (DFT) to study the oxygen release mechanism of CuO carriers, the CuO clusters and slab models were built to simulate the process of cluster and surface oxygen release. CuO slab model’s oxygen release process includes inward oxygen atom diffusion, the formation of O2 molecule in surface and the release of O2 molecule. The results indicate that the highest energy barrier during the CuO(111) surface oxygen release is 3.16 eV, which is close to the experiment value 3.39 eV, but lower than that of CuO cluster model. And besides, the energy barrier of oxygen atom diffusion inside the CuO(111) is just 0.87 eV, indicating that the surface oxygen molecules’ formation process is the rate-limit step of CuO(111) oxygen release.
FENG Xiao-ming , FENG Yong-xin , LIU Ya-ming , LI Fang-yong . Oxygen Release Mechanisms of Cu-Based Oxygen Carriers Based on Density Functional Theory Calculations[J]. Advances in New and Renewable Energy, 2016 , 4(5) : 393 -398 . DOI: 10.3969/j.issn.2095-560X.2016.05.009
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