Doped Mn modulates the local charge distribution of cobalt-based spinel catalysts to promote the availability of ligand lattice oxygen for complete oxidation of methane

• Published in: Applied catalysis. B, Environmental Environmental, 2024-04, Vol.343, p.123547, Article 123547
• Main Authors: Song, Linghe, Zhang, Hang, Xiong, Juxia, Chen, Ziyang, Liu, Yue, Zhou, Haitao, Yang, Weixing, Cao, Dahua, Huang, Haomin, Chen, Limin, Fu, Mingli, Ye, Daiqi
• Format: Article
• Language: English
• Subjects: Lattice oxygen activation; Local charge distribution; Methane oxidation; Mn doping; Spinel Co3O4
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2023.123547

Doping other metals such as Mn, Ni, In, et al. is known as an effective strategy to improve the environmental catalytic performance of Co3O4. In our works, Mn ions were successfully incorporated into the lattice of Co3O4 via the oxalic acid synchronous complexation method. The Mn ions preferentially occupy octahedrally coordinated Co3+ sites and constructing the Mn-O-Co structure. In addition, theoretical calculation further verified that the enhanced catalytic performance of Co5Mn1 originated from highly reactive lattice oxygen coordinated with both Mn and Co ions. Significantly, Mn ions transfer more electrons to lattice oxygen. This oxygen sites have the lower oxygen vacancy formation energy (EOv = 1.94 eV), allowing the lattice oxygen to participate in the reaction following the MvK mechanism in the high temperature range. Collectively, this work is helpful to understand the mechanism of effect of Mn ion doping on the physical and chemical properties of Co-based catalysts. [Display omitted] ●The doped Mn ions occupy the octahedral sites with Mn3+ or Mn4+.●Induced oxygen vacancies improve the catalytic activity by facilitating the conversion of key intermediate species.●Mn ions modulate the local charge of the Mn-O-Co structure, and the orbital hybridization enhances the electron transfer.