Potential of CoMn2O4 spinel as soot oxidation catalyst and its kinetics thereof

R Nithya; Sunaina S Patil; Hari Prasad Dasari; Harshini Dasari; S Nethaji

doi:10.1038/s41598-025-85736-2

Potential of CoMn₂O₄ spinel as soot oxidation catalyst and its kinetics thereof

Sci Rep. 2025 Jan 7;15(1):1174. doi: 10.1038/s41598-025-85736-2.

Authors

R Nithya¹, Sunaina S Patil², Hari Prasad Dasari², Harshini Dasari³, S Nethaji¹

Affiliations

¹ Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, 576104, Manipal, Karnataka, India.
² Energy & Catalysis Materials Laboratory, Department of Chemical Engineering, National Institute of Technology Karnataka, 575025, Surathkal, Mangalore, India.
³ Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, 576104, Manipal, Karnataka, India. harshini.dasari@manipal.edu.

Abstract

Efficient catalysts for soot oxidation are critical for mitigating environmental pollution. In this study, CoMn₂O₄ spinel catalysts were synthesised using reverse co-precipitation and co-precipitation methods to evaluate their performance in soot oxidation and kinetic behaviour. All samples exhibited a tetragonal phase (XRD) and spherical morphology with rough surfaces (SEM). Raman spectroscopy confirmed structural disorder and oxygen vacancies, while XPS analysis revealed the presence of low-valence Mn ions, facilitating oxygen vacancy formation critical for soot oxidation. Additionally, the co-existence of Co and Mn ions contributed to a synergistic effect, enhancing the catalytic properties of the spinel structure. The reverse co-precipitation method produced a catalyst with a higher concentration of oxygen vacancies and active oxygen species among the samples. This sample demonstrated superior catalytic performance, achieving a T_50% of 424 °C, low activation energy (153 kJ/mol) and pre-exponential factor (25 min^{- 1}). Soot TPR analysis highlighted the role of catalyst reducibility, while thermogravimetric analysis revealed that activation energy and pre-exponential factors were influenced by surface composition. These findings provide valuable insights into the design of efficient catalysts for soot oxidation, emphasising the importance of synthesis methods and surface characteristics.

Keywords: Reverse co-precipitation; Soot oxidation; Soot oxidation kinetics; Spinel oxide.