Jiang Ye, Zhang Guomeng, Liu Tianyu, Yang Zhengda, Xu Yichao, Lin Riyi, Wang Xinwei
College of New Energy, China University of Petroleum (East China), 66 West Changjiang Road, Qingdao 266580, China; Qingdao Engineering Research Center of Efficient and Clean Utilization of Fossil Energy, Qingdao 266580, China.
College of New Energy, China University of Petroleum (East China), 66 West Changjiang Road, Qingdao 266580, China; Qingdao Engineering Research Center of Efficient and Clean Utilization of Fossil Energy, Qingdao 266580, China.
J Hazard Mater. 2022 May 15;430:128434. doi: 10.1016/j.jhazmat.2022.128434. Epub 2022 Feb 4.
CeO/TiO catalyst is a promising material for realizing the integration of denitrification and mercury removal to reduce mercury emissions. Oxidation mechanism of Hg on CeO/TiO (001) surface in the presence of HCl and O was studied by density functional theory (DFT). The results indicated that Hg was physically adsorbed on CeO/TiO (001) surface. As an important intermediate, HgCl was adsorbed on the surface of CeO/TiO (001) utilizing enhanced chemisorption, while the adsorption energy of HgCl was only -57.05 kJ/mol. In the absence of HCl, mercury oxidation followed the Mars-Maessen mechanism with a relatively high energy barrier, and the product (HgO) was difficult to desorb, which hindered the reaction process. When HCl existed, reactive chlorine (Cl*) would be produced by the dissociation of HCl, and the mercury oxidation would follow the Langmuir-Hinshelwood mechanism. The co-existence of HCl and O had no significant effect on the adsorption of Hg, but reduced the reaction energy barrier and the final product (HgCl) was more easily desorbed from the catalyst surface. In addition, two complete cyclic reaction pathways for catalytic oxidation of Hg on CeO/TiO (001) surface were constructed to clarify the detailed reaction process.
CeO/TiO催化剂是实现脱硝与汞去除一体化以减少汞排放的一种很有前景的材料。采用密度泛函理论（DFT）研究了在HCl和O存在下Hg在CeO/TiO(001)表面的氧化机理。结果表明，Hg物理吸附在CeO/TiO(001)表面。作为重要中间体，HgCl通过增强的化学吸附作用吸附在CeO/TiO(001)表面，而HgCl的吸附能仅为-57.05kJ/mol。在没有HCl的情况下，汞氧化遵循Mars-Maessen机理，具有较高的能垒，产物（HgO）难以脱附，这阻碍了反应进程。当存在HCl时，HCl的解离会产生活性氯（Cl*），汞氧化将遵循Langmuir-Hinshelwood机理。HCl和O的共存对Hg的吸附没有显著影响，但降低了反应能垒，最终产物（HgCl）更容易从催化剂表面脱附。此外，构建了CeO/TiO(001)表面Hg催化氧化的两条完整循环反应路径，以阐明详细的反应过程。
