Ceria-modified Pt/Al₂O₃ catalyst has been commonly prepared by the impregnation of platinum on ceria-modified alumina and widely applied in the chemical industry and automotive industry. The in situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS), and thermogravimetric (TG) analysis techniques were employed to investigate the typical mechanisms of the bis(ethanolammonium)hexahydroxyplatinate(IV) and cerium nitrate decomposition catalyzed by Pt^δ+ species for the facile synthesis of CeO₂-Pt/Al₂O₃ catalyst. It was found that Pt⁴⁺-catalyzed decomposition of cerium nitrate leads to the higher dispersity of ceria and forming more active oxygen species, on the basis of X-ray diffraction (XRD) and H₂ temperature-programmed reduction (H₂-TPR) results. The in situ activity measurements were also performed to investigate the reaction mechanisms and the specific activities for the catalytic CO, NO, C₃H₆ and C₃H₈ co-oxidation. The results indicate that undesirable N₂O by-product is formed by the selective catalytic reduction (SCR) of NO by C₃H₆ below 350 °C. The cerium addition effectively improves the activity of catalytic oxidation, but exhibits an increased N₂O yield, due to the increased reducibility.

The interface structure of a new Nb/Re laminated composite is designed by density functional theory (DFT), and its mechanical properties are verified by experiments. The results show that the new Nb7Re8 composite has excellent hardness (21.3 GPa) and toughness (BH/GH= 1.8), which are calculated using a thermodynamic phase diagram and first principles. In addition, the new composite consists of a Nb layer, a transition layer (Nb7Re8 and NbRe3 phase) and a Re layer, which are smooth, uniform and dense. In particular, the transition layer consists of the Nb7Re8 phase and has a zigzag structure, which effectively improves the interfacial bonding properties of the composite. The density of the composite is 12.23 g/cm3, which is only 58.2% of the Re density (ρRe = 21.04 g/cm3), and the tensile strength is 636 MPa. This new Nb/Re laminated composite can be widely used as a high temperature resistant structural material for aerospace engine nozzles.

The oxygen reduction reaction (ORR) at the cathode remains a major kinetic bottleneck for proton-exchange-membrane fuel cells, and Pt-Co alloying is a well-established strategy for boosting Pt-mass-normalized ORR activity. However, the long-term durability of such alloys is limited by two largely independent degradation pathways, dealloying-induced Co leaching and nanoparticle coalescence, that are rarely addressed simultaneously. Here, a series of Pt_xCo_y/C-H₂ catalysts with varying Pt:Co ratios were synthesized via gel-confined co-reduction of Pt and Co precursors, phosphoric-acid-assisted carbonization into a mesoporous carbon support, and a subsequent H₂-annealing step. XRD confirmed Pt-Co alloy formation with composition-dependent lattice contraction, while XPS showed that surface Pt:Co ratios consistently exceeded the nominal feed ratios across all compositions, indicating H₂-annealing-induced Pt surface segregation and the formation of a Pt-enriched, core–shell-like architecture, further supported by TEM/EDS line-scan profiles. Among the series, Pt₃Co₁/C-H₂ delivered ORR activity (E_1/2, mass activity, and specific activity) essentially comparable to commercial Pt/C while reducing Pt loading by approximately 9 wt%, and retained the intrinsic four-electron ORR pathway (n = 3.78). After accelerated durability testing (10,000 cycles), Pt₃Co₁/C-H₂ exhibited smaller E_1/2 decay than Pt/C (48 vs. 52 mV), which is attributed to the concurrent suppression of nanoparticle coalescence by mesopore confinement and of Co leaching by the Pt-enriched surface. These results establish a generalizable design principle for decoupling the dominant degradation pathways of Pt-transition-metal alloy ORR catalysts while reducing precious-metal content.

To meet the demands for high-temperature performance and lightweight materials in aerospace engineering, the Au-Ni solder is often utilized for joining dissimilar materials, such as Ti₃Al-based alloys and Ni-based high-temperature alloys. However, the interaction between Ti and Ni can lead to the formation of brittle phases, like Ti₂Ni, TiNi, and TiNi₃, which diminish the mechanical properties of the joint and increase the risk of crack formation during the welding process. Cu doping has been shown to enhance the mechanical properties and high-temperature stability of the Au-Ni brazed joint’s central area. Due to the difficulty in accurately controlling the solid solution content of Cu in the Au-Ni alloy, along with the high cost of Au, traditional experimental trial-and-error methods are insufficient for the development of Au-based solders. In this study, first principles calculations based on density functional theory were employed to analyze the effect of Cu content on the stability of the Au-2.0Ni-xCu (x = 0, 0.25, 0.5, 0.75, 1.0, 1.25 wt%) alloy phase structure. The thermal properties of the alloy were determined using Gibbs software fitting. The results indicate that the Au-2.0Ni-0.25Cu alloy exhibits the highest plastic toughness (B/G = 5.601, ν = 0.416, Cauchy pressure = 73.676 GPa) and a hardness of 1.17 GPa, which is 80% higher than that of Au-2.0Ni. This alloy balances excellent strength and plastic toughness, meeting the mechanical performance requirements of brazed joints. The constant pressure specific heat capacity (C_p) of the Au-2.0Ni-xCu alloy is higher than that of Au-2.0Ni and increases with Cu content. At 1000 K, the C_p of the Au-2.0Ni-0.25Cu alloy is 35.606 J·mol⁻¹·K⁻¹, which is 5.88% higher than that of Au-2.0Ni. The higher C_p contributes to enhanced high-temperature stability. Moreover, the linear expansion coefficient (CTE) of the Au-2.0Ni-0.25Cu alloy at 1000 K is 8.76 × 10⁻⁵·K⁻¹, only 0.68% higher than Au-2.0Ni. The lower CTE helps to reduce the risk of solder damage caused by thermal stress. Therefore, the Au-2.0Ni-0.25Cu alloy is more suitable for brazing applications in high-temperature environments due to its excellent mechanical properties and thermal stability. This study provides a theoretical basis for the performance optimization and engineering application of the Au-2.0Ni-xCu alloy as a gold-based solder.

Silver-based alloys are irreplaceable in high-reliability electrical contacts because silver has the highest electrical conductivity of all metals, yet its low strength and the intrinsic strength–ductility trade-off limit their use under increasingly severe service conditions. Internal oxidation—the selective in situ oxidation of reactive solutes in a chemically inert Ag matrix—converts these solutes into fine, dispersed oxides, thereby strengthening the alloy. This review critically assesses internal oxidation in silver-based alloys. The thermodynamic and kinetic criteria for selective oxidation are summarized, together with the Wagner diffusion-controlled framework describing the oxidation front. Using Ag-Mg and Ag-Sn as archetypal systems, we trace the microstructural evolution from coherent Mg-O nanoclusters and dispersed SnO₂ particles to deleterious banded oxides, identifying band formation and under-oxidized cores as the two characteristic microstructural defects. The roles of temperature, time, oxygen partial pressure and third-element additions (Te, In, Sb, Bi, Ni) in widening the process window and refining the oxide dispersion are examined. Orowan bypassing, coherency strain and Hall–Petch grain refinement, and their coupling with microstructural characteristics, are discussed to provide guidelines for alloy design. Finally, outstanding questions and opportunities, including atomic-scale in situ characterization, predictive multiscale modeling and novel processing routes, are outlined.