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Reducing the preparation cost of alumina ceramics has received significant attention, as alumina is one of the most widely used structural ceramics. In this study, corundum-based composite ceramics with a white corundum-to-zircon powder mass ratio of 7:3 were selected as the matrix. CeO2 and Y2O3 doped corundum-based composite ceramics were prepared via pressureless sintering. The total content of CeO2-Y2O3 was set at 10 wt% to study the effects of different temperatures and CeO2-Y2O3 ratios on the properties of the corundum-based composite ceramics. Physical phase and microstructural analyses of the corundum-based composite ceramics were performed using X-ray diffraction and scanning electron microscopy, respectively. The results showed that the sintering temperature of the corundum-based composite ceramics could be effectively reduced by using a solid solution of CeO2 and Y2O3. The best sintering temperature was 1400°C, and the best composition was 5 wt% CeO2-5 wt% Y2O3. The physical properties of the corundum-based composite ceramics prepared under these technological conditions include a flexural strength of 386.2 MPa, hardness of 13.5 GPa, density of 3.9128 g/cm3, linear shrinkage of 16.31% and an apparent porosity of 0.62%. [ABSTRACT FROM AUTHOR]

It's crucial to make inexpensive, effective palladium catalysts employing α-alumina in the realms of pollution remediation and drug synthesis. The α-alumina foam ceramics prepared by the template approach were modified by adding a thin coating of γ-alumina containing Ce and P elements to further prepare the palladium catalyst. γ-Alumina significantly raised the foam's specific surface area, multiplied the number of acidic sites, decreased the Pd–O bond strength in palladium oxide, and brought the active phase content closer to the ideal value. Phosphate radicals were adsorbed onto the alumina surface, reducing the proportion of strongly acidic sites on the surface, and facilitating the desorption of oxygen species adsorbed by surface defects. As P and Ce elements interacted, the Ce4+/Ce3+ ratio decreased, increasing the number of oxygen vacancies in cerium oxide to improve the oxygen storage capacity of cerium oxide. In addition to acting as an oxygen storage material, the Ce elements increased the electron density of Pd and weakened the binding strength of the oxygen species bound to the individual metal Pd. There was a strong interaction between cerium and palladium, resulting in a mixed state of Pd0, PdO, and Pd2+ after the reaction. On the other hand, the surface of the foam was rough enough to facilitate the adhesion of the thin coating, while the thin coating, with a thickness of less than 8 μm, improved its mechanical properties. The CO full conversion temperature was reduced by 135 °C in the Pd/CeP(γ/α-A) compared to the uncoated foam catalyst. [ABSTRACT FROM AUTHOR]

Ti3SiC2/Al2O3 multilayered composites were prepared by the combination of tape casting and hot pressing sintering. The slurry was produced by adjusting the amounts of each organic material, including triethyl phosphate (TEP) as a dispersion, polyvinyl butyrate (PVB) as a binder, dioctyl phthalate (DOP) as a plasticizer, and anhydrous ethanol as an organic solvent. When TEP content was 3 wt.%, PVB content was 4.5 wt.%, R‐value (DOP/PVB) was 1.4, and solid content was 38 wt.%; the cast film with a smooth surface, good flexibility, and uniform thickness was obtained after defoaming, tape casting, and drying. Three samples were prepared, namely, S1–S3. The S1 was monolithic Ti3SiC2/Al2O3 (mass ratio is 1:1) composites. S2 and S3 were Ti3SiC2/Al2O3 multilayered composites, which matrix layers were Ti3SiC2/Al2O3 composites (mass ratio is 1:1) and Al2O3, respectively, and their interface layer was Ti3SiC2. S1–S3 were also sintered at 1550°C. The bending strength of multilayered materials were lower than that of monolithic material, but the fracture toughness of multilayered materials significantly increased. Due to the introduction of Ti3SiC2 interface layer, the friction coefficient and wear rate of Ti3SiC2/Al2O3 multilayered composites were reduced by 30.7% and 33.8%, respectively, compared with monolithic material. [ABSTRACT FROM AUTHOR]

Ammonia, with its high hydrogen content, serves as an optimal carbon-free medium for indirect hydrogen storage, making it ideal for fuel cells. Nevertheless, the limited anodic catalytic activity of Proton-conducting solid oxide fuel cells (PCFCs) significantly hampers NH 3 utilization efficiency and overall performance. This study introduces efficient nano-catalysts deposited onto dendritic anodic microchannels, leading to the formation of an in-situ ammonia decomposition reactor for internal ammonia gas conversion. Compared to conventional cells, this cell, equipped with a catalyst bed, shows a 25% increase in peak power density and a 20%–30% enhancement in NH 3 utilization efficiency. Additionally, ammonia undergoes efficient decomposition on anodic metallic nickel, which prevents nickel nitridation and improves cell stability. The augmented stability of these cells is evidenced by their prolonged operational lifespan under constant current conditions, extending from 63 to 108 h, thus marking a substantial enhancement in the system's durability and reliability. • Ammonia is a storable, hydrogen-rich, carbon-free fuel highly compatible with PCFCs. • "Ammonia replace efficiency" characterizes ammonia fuel utilization rate in PCFCs. • Dendritic porous anode enables efficient catalyst loading for ammonia decomposition. • Ru-GDC fiber catalysts in porous anodes enhance catalytic reformer performance. [ABSTRACT FROM AUTHOR]