Potential of CoMn2O4 spinel as soot oxidation catalyst and its kinetics thereof
R. Nithya, Sunaina S. Patil, Hari Prasad Dasari, Harshini Dasari, S. Nethaji, Harshini Dasari, S. Nethaji
Abstract
Abstract Efficient catalysts for soot oxidation are critical for mitigating environmental pollution. In this study, CoMn 2 O 4 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.