Zhang Yingjie, Yu Huijuan, Wang Xueqian, Wang Langlang, Li Yuancheng, Lv Dongpeng, Zhu Dan, Tian Chunmei
College of Agriculture and Biological Science, Dali University, Dali, 671000, China.
Key Laboratory of Ecological Microbial Remediation Technology of Yunnan Higher Education Institutes, Dali University, Dali, 671000, China.
J Mol Model. 2022 May 18;28(6):156. doi: 10.1007/s00894-022-05153-4.
Ceria (CeO)-based materials are potential catalysts for the removal of the Hg and AsH present in reducing atmospheres. However, theoretical studies investigating the Hg and AsH removal capacity of ceria remain limited. In this study, the adsorption behavior and mechanistic pathways for the catalytic oxidation of Hg and AsH on the CeO(111) surface, including the calculation of optimized adsorption configurations and energies, were investigated using density functional theory calculations. The results suggest that Hg and AsH are favorably adsorbed on the CeO(111) surface, whereas CO is not, which is crucial for selective removal when CO is a desirable gas component. Furthermore, AsH is adsorbed more favorably than Hg. In addition, the calculations revealed that the Hg atom is initially adsorbed on the surface and then oxidized by lattice oxygen to form HgO. Concerning AsH decomposition, the stepwise dehydrogenation of AsH followed by bonding with lattice O atoms to form the As-O bond seems the most plausible. Finally, the adsorbed As-O bond is further forms elemental As and AsO. Therefore, CeO can adsorb and remove Hg and AsH, making it a promising catalyst for the simultaneous catalytic oxidation of Hg and AsH in strongly reducing off-gas.
基于二氧化铈（CeO）的材料是用于去除还原气氛中存在的汞（Hg）和砷化氢（AsH）的潜在催化剂。然而，研究二氧化铈对汞和砷化氢去除能力的理论研究仍然有限。在本研究中，使用密度泛函理论计算研究了Hg和AsH在CeO(111)表面催化氧化的吸附行为和机理途径，包括优化吸附构型和能量的计算。结果表明，Hg和AsH在CeO(111)表面上易于吸附，而CO则不然，当CO是所需气体成分时，这对于选择性去除至关重要。此外，AsH比Hg更易于吸附。此外，计算表明Hg原子最初吸附在表面上，然后被晶格氧氧化形成HgO。关于AsH的分解，AsH逐步脱氢然后与晶格O原子键合形成As-O键似乎是最合理的。最后，吸附的As-O键进一步形成元素As和AsO。因此，CeO可以吸附和去除Hg和AsH，使其成为在强还原废气中同时催化氧化Hg和AsH的有前景的催化剂。
