In the present paper, the perovskites SrMnO3, SrMn0.98Co0.02O3 (SMCo), SrMn0.98Cu0.02O3 (SMCu) were synthesized using the sol-gel method. The as-prepared samples were extensively characterized using XRD, BET surface area, SEM/EDS analysis, XPS, H2-TPR, O2-TPD, and soot-TPR analysis. The samples were tested for soot oxidation reactions and the possible reaction mechanism on the surface of the prepared samples was also proposed. XRD patterns emphasized that all the samples (host and the doped samples) exhibited a stable hexagonal phase. XPS results evidenced Sr2+, Mn4+/Mn3+, Co3+/Co2+ and Cu2+ cations on the surface of the perovskites. The O1s peaks reveal that the Co and Cu doped samples exhibited more active oxygen (O2 -, O−) compared with the un-doped sample. Moreover, the percentage of active oxygen species (%) in the samples SrMnO3, SMCo and SMCu were 58.9%, 63.6%, and 61.7% respectively. H2-TPR experiments reveal that the low-temperature reduction peaks were shifted towards the lower temperature upon doping of Co, Cu in SrMnO3 perovskite. Besides, the overall H2 uptake for SMCo sample was higher than the others because of the successive reductions of Co3+/Co2+ and Mn4+/Mn3+/Mn3+ cations. O2-TPD experiments evidenced that the mobility of active oxygen species was higher for SMCo sample (0.0995 mmol/g), which is consistent with the results obtained from the O1s analysis. The soot oxidation experiments reveal that the catalytic property of the samples was in the order SMCo > SMCu > SM > un-catalyzed soot. The estimated activation energies of the doped and un-doped perovskite were in the range of 65 to 80 kJ/mol, which was nearly half the activation energy of the un-catalyzed soot (134 kJ/mol).
All Science Journal Classification (ASJC) codes
- Process Chemistry and Technology
- Physical and Theoretical Chemistry