Abstract Density functional theory (DFT) calculations are employed to investigate the reaction mechanisms of H2S or COS with CuO in this work, including the microscopic adsorption, dissociation, and further reactions over the perfect (fresh) and defect (partially reduced) CuO (111) surfaces. On the perfect surface, the elementary reaction of HS* → H* + S* is the rate-determining step in the two-step H2S dissociation process, and the formation of H2O is however the rate-determining step for the whole reaction between H2S and CuO. As for the defect surface, the reaction of H2O formation is still a more preferable pathway than the complete dissociation and H2 formation route. In view of COS decomposition on the perfect surface, the energy barriers for the formation of CO or CO2 from COS decomposition are too high, and thus are difficult to take place. On the defect surface, the presence of oxygen vacancy greatly promotes the adsorption and subsequent decomposition of COS. Finally, the remaining sulfur favorably exists on the surface rather than SO2 formation, and copper sulfides will inevitably generate as the dissociations of H2S or COS proceed. The results attained in this work are helpful to give insights into the sulfur evolution of sulfur-containing fuels in the chemical looping combustion process.

中文翻译：

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化学循环燃烧中H2S、COS与CuO载氧体的微观反应机理探讨

摘要 本文采用密度泛函理论 (DFT) 计算来研究 H2S 或 COS 与 CuO 的反应机理，包括微观吸附、解离以及在完美（新鲜）和缺陷（部分还原）CuO (111 ) 表面。在完美的表面上，HS*→H*+S*的基元反应是两步H2S解离过程中的定速步骤，而H2O的形成是H2S之间整个反应的定速步骤和氧化铜。对于缺陷表面，H2O 形成反应仍然是比完全解离和 H2 形成路线更优选的途径。鉴于完美表面上的 COS 分解，COS 分解生成 CO 或 CO2 的能垒太高，难以发生。在缺陷表面，氧空位的存在极大地促进了 COS 的吸附和随后的分解。最后，剩余的硫有利地存在于表面而不是 SO2 的形成，随着 H2S 或 COS 的解离，硫化铜将不可避免地产生。在这项工作中获得的结果有助于深入了解化学循环燃烧过程中含硫燃料的硫演变。