化学链燃烧中H2S与CuFe2O4载氧体的反应机理

基于密度泛函理论和周期性结构模型，在分子水平上研究了化学链燃烧中H2S与CuFe2O4载氧体表面相互作用的微观反应机理。结果表明，H2S分子解离的SH、S和H基团倾向于吸附在O.1原子顶位上。H2S分子在CuFe2O4载氧体表面发生的反应主要包括3个步骤：H2S分子吸附、H2S脱氢和H2O分子形成。首先H2S吸附在CuFe2O4载氧体表面进而发生两步脱氢反应，随着反应的进行，产生的H2O分子从载氧体表面脱附，CuFe2O4载氧体表面的S基团发生迁移并填入氧空位形成硫化表面。其中H2O分子的形成需克服135.57 kJ/mol的反应能垒，为速控步骤。围绕Cu原子进行的反应路径是H2S与CuFe2O4载氧体表面反应的主要路径，与实验结果吻合。

Interaction Mechanism Between H2S and CuFe2O4 Oxygen Carrier in Chemical-Looping Combustion

Based on density function theory and periodic structural model, the interaction mechanism between H2S and CuFe2O4 surface was studied at the molecular level. The results show that SH, S and H species dissociated from H2S molecule tend to be adsorbed on the most active O.1 atom. The interaction between H2S and CuFe2O4 mainly consists of three steps: adsorption of H2S molecule, dehydrogenation of H2S, and H2O molecule formation. H2S molecule adsorbs on the CuFe2O4 surface firstly and then the two-step dehydrogenation of H2S occurs. As the reaction proceeds, H2O molecule desorbs form the CuFe2O4 surface, the S species migrates and fills in the oxygen vacancy to form vulcanized surface. The formation of H2O molecule is the rate-determining step with an energy barrier being 135.57 kJ/mol. The pathway concentrated on the surface Cu atom is the main reaction pathway between H2S and CuFe2O4, which is consistent with experimental results.