Catalysts are very important in controlling the pollutant emissions and are used for hundreds of chemical processes. Currently, noble metal-based catalysts are being replaced for other kinds of materials. In this study, three lanthanum-based perovskite-like oxides were synthesized (LaCo, LaCoMn, and LaMn) by the glycine-combustion method. The powder catalysts obtained were supported onto cordierite ceramic monoliths using an optimized washcoating methodology to obtain the subsequent monolithic catalysts (LaCo-S, LaCoMn-S, and LaMn-S). Sample characterization confirmed the formation of the perovskite-like phase in the powder materials as well as the presence of the perovskite phase after supporting it onto the monolithic structure. The XPS analysis showed a general decrease in lattice oxygen species for monolithic catalysts, mainly caused by the colloidal silica used as a binder agent during the washcoating process. Additionally, some variations in the oxidation state distribution for elements in Co-containing systems suggest a stronger interaction between cordierite and such catalysts. The catalytic activity results indicated that powder and monolithic catalysts were active for single-component VOC oxidation in the following order: 2-propanol > n-hexane ≅ mixture > toluene, and there was no evidence of loss of catalytic activity after supporting the catalysts. However, LaMn-S had a better catalytic performance for all VOC tested under dry conditions, achieving oxidation temperatures between 230–420 °C. The oxidation efficiency for the VOC mixture was strongly affected by the presence of moisture linking the oxidation efficiency at wet conditions to the VOC chemical nature. Additionally, for higher VOC concentrations, the catalyst efficiency decreased due to the limited number of active sites.

The aim of this work is to study the influence of the molecular structure of fatty acid esters present in biodiesel and their blends with diesel on the chemical characteristics of the emitted particulate matter. Biodiesel produced from palm oil, jatropha, castor oil and sachainchi was blended at 5% and 20% by volume with diesel. These fuels were used for the operation of a four-cylinder direct injection automotive diesel engine. The equivalent ratio was kept between 0.36 and 0.40, and the engine was operated at the point of minimum air–fuel ratio and maximum smoke opacity. The amount of particulate matter emitted was evaluated by opacity index. A marked reduction in soot formation was observed when the concentration of unsaturated methyl esters in the fuel was at low concentrations. This was accompanied by a reduction of the aliphatic carbon content in the particulate matter.

A crucial characteristic of perovskite-like oxides is oxygen mobility, which can be enhanced by inducing structural defects through stoichiometry variations during synthesis, thereby boosting the catalytic activity. This study evaluated the effect of structural modifications of LaFeO₃ (LF) and LaMnO₃ (LM) perovskites series on the total oxidation of 2-propanol as a VOC model, a well-known organic solvent. These modifications were performed during synthesis by partially removing the B-site cation or by structural doping in the B-site with another cation (Mn for the LF series and Pd for the LM series). Structural characterization was carried out by XRD and Raman spectroscopy, while the bulk and surface chemical composition were assessed by ICP and XPS, respectively. On the other hand, catalytic activity was performed using a reactivity test with the 2-propanol molecule. The CO-TPR and O₂-TPD measurements were used to characterize the reducibility of the active phase, and the type of oxygen species present in the sample. The catalytic activity results indicated that the modified perovskites showed a difference of 118 °C and 109 °C in the T₉₅ parameter (Temperature at which the conversion of 2-propanol was 95%) relative to pure LF and LM perovskites, respectively. It was also observed that the inclusion of cationic species with high oxidation states enhances the catalytic properties of the materials not only for the doped perovskites but also for the impregnated ones used for comparison purposes. This research demonstrated that stoichiometric variations in modified perovskite-like catalysts significantly improve the catalytic capacity by forming structural defects and modifying redox properties.Kindly check and confirm whether the corresponding author is correctly identified.I confirm that the corresponding author is well identified Graphical Abstract