关键词: 化学链燃烧, H₂S, CuFe₂O₄, 复合载氧体；反应机理；密度泛函理论

Abstract:

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.

Key words: chemical-looping combustion; H₂S, CuFe₂O₄, composite oxygen carrier, interaction, density functional theory