Continuously regenerating Diesel Particulate Filters based on ionically conducting ceramics

Uncovering Key Factors in Graphene Aerogel-Based Electrocatalysts for Sustainable Hydrogen Production: An Unsupervised Machine Learning Approach

The application of principal component analysis (PCA) as an unsupervised learning method has been used in uncovering correlations among diverse features of aerogel-based electrocatalysts. This analytical approach facilitates a comprehensive exploration of catalytic activity, revealing intricate relationships with various physical and electrochemical properties. The first two principal components (PCs), collectively capturing nearly 70% of the total variance, attested the reliability and efficacy of PCA in unveiling meaningful patterns. This study challenges the conventional understanding that a material's reactivity is solely dictated by the quantity of catalyst loaded. Instead, it unveils a complex perspective, highlighting that reactivity is intricately influenced by the material's overall design and structure. The PCA bi-plot uncovers correlations between pH and Tafel slope, suggesting an interdependence between these variables and providing valuable insights into the complex interactions among physical and electrochemical properties. Tafel slope stands to be positively correlated with PC1 and PC2, showing an evident positive correlation with the pH. These findings showed that the pH can have a positive correlation with the Tafel slope, however, it does not necessarily reflect a direct positive correlation with the overpotential. The impact of pH on current density (j)and Tafel slope underscores the importance of adjusting pH to lower overpotential effectively, enhancing catalytic activity. Surface area (from 30 to 533 m2 g-1) emerges as a key physical property, inclusively inverse correlation with overpotential, indicating its direct role in lowering overpotential and increasing catalytic activity. The introduction of PC3, in conjunction with PC1, enriches the analysis by revealing consistent trends despite a slightly lower variance (60%). This reinforces the robustness of PCA in delineating distinct characteristics of graphene aerogels, affirming their potential implications in diverse electrocatalytic applications. In summary, PCA proves to be a valuable tool for unraveling complex relationships within aerogel-based electrocatalysts, extending insights beyond catalytic sites to emphasize the broader spectrum of material properties. This approach enhances comprehension of dataset intricacies and holds promise for guiding the development of more effective and versatile electrocatalytic materials.

BaFe1-xCuxO3 Perovskites as Active Phase for Diesel (DPF) and Gasoline Particle Filters (GPF)

BaFe_1−xCu_xO₃ perovskites (x = 0, 0.1, 0.3 and 0.4) have been synthetized, characterized and tested for soot oxidation in both Diesel and Gasoline Direct Injection (GDI) exhaust conditions. The catalysts have been characterized by BET, ICP-OES, SEM-EDX, XRD, XPS, H₂-TPR and O₂-TPD and the results indicate the incorporation of copper in the perovskite lattice which leads to: (i) the deformation of the initial hexagonal perovskite structure for the catalyst with the lowest copper content (BFC1), (ii) the modification to cubic from hexagonal structure for the high copper content catalysts (BFC3 and BFC4), (iii) the creation of a minority segregated phase, BaO_x-CuO_x, in the highest copper content catalyst (BFC4), (iv) the rise in the quantity of oxygen vacancies/defects for the catalysts BFC3 and BFC4, and (v) the reduction in the amount of O₂ released in the course of the O₂-TPD tests as the copper content increases. The BaFe_1−xCu_xO₃ perovskites catalyze both the NO₂-assisted diesel soot oxidation (500 ppm NO, 5% O₂) and, to a lesser extent, the soot oxidation under fuel cuts GDI operation conditions (1% O₂). BFC0 is the most active catalysts as the activity seems to be mainly related with the amount of O₂ evolved during an. O₂-TPD, which decreases with copper content.

Catalytic Soot Oxidation Activity of NiO-CeO2 Catalysts Prepared by a Coprecipitation Method: Influence of the Preparation pH on the Catalytic Performance

A series of NiO-CeO2 mixed oxide catalysts have been synthesized by a modified coprecipitation method at three different pH values (pH = 8, 9, and 10). The NiO-CeO2 mixed oxide samples were characterized by TGA, XRD, inductively coupled plasma atomic emission spectroscopy (ICP-AES), FTIR, Brunauer-Emmett-Teller (BET) surface area, H2 temperature-programmed reduction (H2-TPR), and electron microscopy (high-angle annular dark-field transmission electron microscopy/energy-dispersive X-ray spectroscopy (HAADF-TEM/EDS)). The catalytic activities of the samples for soot oxidation were investigated under loose and tight contact conditions. The catalysts exhibited a high BET surface area with average crystal sizes that varied with the pH values. Electron microscopy results showed the formation of small crystallites (~5 nm) of CeO2 supported on large plate-shaped particles of NiO (~20 nm thick). XRD showed that a proportion of the Ni2+ was incorporated into the ceria network, and it appeared that the amount on Ni2+ that replaced Ce4+ was higher when the synthesis of the mixed oxides was carried out at a lower pH. Among the synthesized catalysts, Ni-Ce-8 (pH = 8) exhibited the best catalytic performance.

Catalytic combustion of diesel soot over Fe and Ag-doped manganese oxides: role of heteroatoms in the catalytic performances

Fe/Ag-doped manganese oxides show promising catalytic activities in diesel soot combustion, which occurviamechanisms involving activated surface/lattice oxygen species.

Facile synthesis of spinel Cu1.5Mn1.5O4 microspheres with high activity for the catalytic combustion of diesel soot

Optimized Cu_1.5Mn_1.5O₄ microspheres, possessing abundant O_ads and active Cu⁺–Mn⁴⁺ sites for NO₂ formation, exhibit excellent activity for soot combustion.

Highly active MnOx–CeO2catalyst for diesel soot combustion

Optimized Ce–Mn composite oxide, possessing abundant active Ce³⁺–Mn⁴⁺ions, exhibits excellent activity for catalytic soot combustion in NO_x/O₂.

Activation and deactivation of Ag/CeO2 during soot oxidation: influences of interfacial ceria reduction

Both the existence of CeO₂ surface oxygen vacancies and their dynamic change during reaction may cause crucial influence on the soot oxidation behavior of Ag/CeO₂.

Promotional effect of cobalt addition on catalytic performance of Ce0.5Zr0.5O2 mixed oxide for diesel soot combustion

A series of Co-modified Ce

Applications of yttria stabilized zirconia (YSZ) in catalysis

The main applications of yttria stabilized zirconia in catalysis are briefly reviewed and analyzed based on its functionalities.

High specific surface area YSZ powders from a supercritical CO2 process as catalytic supports for NOx storage–reduction reaction

The high specific surface area YSZ improves the washcoat dispersion in the porous walls of mini-diesel particulate filters, enhancing both NO conversion and N₂ selectivity.