Faculty Publications
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Item Dip coating of ceria–manganese mixed oxides on cordierite and its CO oxidation activity(Springer Science and Business Media Deutschland GmbH, 2024) Shourya, A.; Prasad Dasari, H.P.; Wagay, A.A.Dip coating method was utilized for wash-coating alumina onto cordierite honeycomb substrate, followed by catalyst coating by sol–gel dip coating of CMX(X = 0, 5, 70, and 100 corresponding to Ce1-xMnxO2-δ, where x = 0, 0.5, 0.7, and 1) to obtain CM0/Al2O3/Cord, CM5/Al2O3/Cord, CM70/Al2O3/Cord, and CM100/Al2O3/Cord. The sol–gel was obtained from the EDTA–citrate method. XRD, BET, and BJH analysis was conducted on samples Cord to CM100/Al2O3/Cord. An intense peak of ceria at 462.53 cm−1 and that of Mn3O4 was observed at 658 cm−1 in the Raman spectra analysis. The adherence test was conducted to test the mechanical stability of the wash-coat and catalyst layer. The visual evidence of coating was furnished by optical imaging and FESEM analysis. Ultrafine particles with high porosity were observed in sample Al2O3/Cord. Cracks were observed in the FESEM images of CM0/Al2O3/Cord to CM100/Al2O3/Cord samples. CO oxidation studies were performed on the samples Cord to CM100/Al2O3/Cord. CM70/Al2O3/Cord performed the best among all other samples with a T50 temperature of 157 °C. The activation energy of CO oxidation was calculated using the Ozawa method for samples CM0/Al2O3/Cord to CM100/Al2O3/Cord. 50 h long-term CO oxidation stability experiments were also conducted on samples CM0/Al2O3/Cord to CM100/Al2O3/Cord. The synergistic effects of ceria and manganese, combined with fine dispersion of the catalyst, pore characteristics, and cracks improving diffusivity, pitched CM70/Al2O3/Cord to have the best CO oxidation activity. © The Author(s), under exclusive licence to the Institute of Chemistry, Slovak Academy of Sciences 2024.Item Study of CO oxidation activity of NiO-PDC and NiO-YSZ catalysts coated on alumina wash-coated honeycomb cordierite monolith(Springer Science and Business Media Deutschland GmbH, 2025) Wagay, A.A.; Shourya, A.; Patil, S.S.; Shirasangi, R.; Prasad Dasari, H.P.In this study, the EDTA-Citrate method was employed to synthesize NiO-PDC (NPC) and NiO-YSZ (NYZ) powder catalysts in nanostructured form. Subsequently, the catalysts were slurry dip-coated onto monolith cordierite substrates with alumina, using a one-step coating approach, and their CO oxidation activity was tested. The coating was achieved by first mixing the catalyst with the alumina suspension to prepare a homogeneous slurry, which was then used for dip coating onto the monolith. The adherence test was performed on the coated monolith to evaluate the mechanical stability of the catalyst-alumina composite layer. The coating was visually confirmed through optical imaging. The remaining powders (after coating) were then subjected to BET surface area, XRD, Raman spectroscopy, H2 TPR and O2 TPD analysis for characterization. Raman spectra showed that NPC exhibited higher oxygen vacancies than NYZ. H2 TPR and O2 TPD provided better evidence of the reduction potential and O2 desorption of NPC respectively. NPC/cord demonstrated the highest catalytic activity (T50 = 165 °C) compared to NYZ/cord (T50 = 215 °C) and bare cordierite (T50 = 777 °C), which is attributed to its better redox properties and higher oxygen vacancies. The effect of flow rate and heating rate on CO oxidation was studied on NPC/cord and NYZ/cord. The long-term stability of the NPC/cord and NYZ/cord were tested through 5-h and 50-h isothermal studies. © The Author(s) under exclusive licence to Associação Brasileira de Engenharia Química 2025.