Simultaneous catalytic oxidation of elemental mercury and arsine over CeO 2 (111) surface: a density functional theory study.

Ceria (CeO 2 )-based materials are potential catalysts for the removal of the Hg 0 and AsH 3 present in reducing atmospheres. However, theoretical studies investigating the Hg 0 and AsH 3 removal capacity of ceria remain limited. In this study, the adsorption behavior and mechanistic pathways for the catalytic oxidation of Hg 0 and AsH 3 on the CeO 2 (111) surface, including the calculation of optimized adsorption configurations and energies, were investigated using density functional theory calculations. The results suggest that Hg 0 and AsH 3 are favorably adsorbed on the CeO 2 (111) surface, whereas CO is not, which is crucial for selective removal when CO is a desirable gas component. Furthermore, AsH 3 is adsorbed more favorably than Hg 0 . 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 3 decomposition, the stepwise dehydrogenation of AsH 3 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 As 2 O 3 . Therefore, CeO 2 can adsorb and remove Hg 0 and AsH 3 , making it a promising catalyst for the simultaneous catalytic oxidation of Hg 0 and AsH 3 in strongly reducing off-gas.