Shi Yiran, Yi Honghong, Gao Fengyu, Zhao Shunzheng, Xie Zongli, Tang Xiaolong
Department of Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China; CSIRO Manufacturing, Private Bag 10, Clayton South, Victoria 3169, Australia.
Department of Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China.
J Hazard Mater. 2021 Jul 5;413:125361. doi: 10.1016/j.jhazmat.2021.125361. Epub 2021 Feb 9.
The unexpected phenomenon in which different transition metals (Co, Ni and Cu) presented significant variation of participation levels as the auxiliaries in Mn-based bimetallic oxide catalysts were reported here. It is found that the Co element more easily to form Mn enriched surface bimetallic oxides with Mn than Ni and Cu, resulting in Co-MnO exhibited the best deNO activity and SO tolerance, followed by Ni-MnO and Cu-MnO. The role of different transition metal and structure-activity relationships were systematically investigated by advanced techniques including Synchrotron XAFS and in situ DRIFTs analysis. The excellent activity of Co-MnO was related to its unique Mn-enriched surface (Co)(Mn Co)O structure with Mn cations occupying the octahedral sites, which is superior to the Ni-MnO and Cu-MnO with Mn-lean surface. In addition, the reaction energy barrier of Co-MnO is weakened due to the lower electron cloud density around the Mn atom as compared to Ni-MnO and Cu-MnO. Moreover, Co-MnO benefiting from the rapid electron migration between Mn and Co, more active bidentate/bridged nitrates could react with adsorbed NH in faster reaction rates following the L-H mechanism.
本文报道了一种意外现象，即在锰基双金属氧化物催化剂中，不同的过渡金属（钴、镍和铜）作为助剂时表现出显著不同的参与水平变化。研究发现，与镍和铜相比，钴元素更容易与锰形成富锰表面双金属氧化物，因此Co-MnO表现出最佳的脱硝活性和抗硫性能，其次是Ni-MnO和Cu-MnO。通过同步辐射XAFS和原位DRIFTs分析等先进技术系统地研究了不同过渡金属的作用及其结构-活性关系。Co-MnO的优异活性与其独特的富锰表面(Co)(Mn Co)O结构有关，其中锰阳离子占据八面体位置，优于贫锰表面的Ni-MnO和Cu-MnO。此外，与Ni-MnO和Cu-MnO相比，Co-MnO中锰原子周围的电子云密度较低，使得反应能垒降低。此外，Co-MnO得益于锰和钴之间的快速电子迁移，更多活性的双齿/桥连硝酸盐能够按照L-H机理以更快的反应速率与吸附的NH反应。
