With unique mechanical properties and excellent thermal and chemical stability, Al₂O₃ nanofibers are highly desirable for practical applications as functional and structural building blocks. However, the scalable production of Al₂O₃ nanofibers has always been confronted with significant challenges, namely the high cost and complicated processes. This work explores a feasible and straightforward dealloying strategy for the batch synthesis of Al₂O₃ nanofibers. When a binary Al-Li alloy is immersed in alcohol, the alkoxide nanofibers will spontaneously grow following the mechanism of boundary strain energy minimization. The results indicate that by dissolving Li in Al-Li alloys, the continuous exposure of a fresh Al surface renders the remaining unsaturated bonds of Al sufficiently reactive, providing the conditions for the subsequent reaction with alcohols and thus inducing the formation of alcohol-aluminum compounds. These nanofibers were calcined in air to obtain monocrystalline α-Al₂O₃ and polycrystalline γ-Al₂O₃ nanofibers. We investigated the evolution of the alloy to nanofibers in dry ethanol and the influence of different Al-Li alloy compositions and calcination temperatures on the crystal structure and morphology of the resulting Al₂O₃ nanofibers. The study reveals that γ-Al₂O₃ with diameters of approximately 50-80 nm and lengths of around 20-30 μm, and α-Al₂O₃ with diameters of about 100-150 nm and lengths of approximately 15-20 μm were successfully prepared by this technique route. The approach reported in this study is anticipated to open up new paths for the efficient and economical synthesis of advanced metal oxide nanofibers and lay the foundation for their extensive application in current industrial sectors.

Physical properties, such as electrochemical and electromagnetic properties, of two-dimensional MXenes can be improved by enhancing their stability. However, MXenes fabricated via acid etching contain defects, which affect their physical properties. In this study, a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is proposed. The fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H₂O-etched Cr₂(AlLi)C. On the basis of this mechanism, the room-temperature ferromagnetism of two-dimensional few-layered Cr₂CT_x MXenes, which has a specific saturation magnetization of ~0.26 emu/g and a Curie temperature of > 353 K, is experimentally verified. The calculated electronic band structure implies that the semimetal Cr₂CT_x MXene has a band gap of 0.75 eV. This study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.

Highly pure and dense Ti₂AlC and Ti₂AlSn_0.2C bulks were prepared by hot pressing with molar ratios of 1:1.1:0.9 and 1:0.9:0.2:0.85, respectively, at 1450 ℃ for 30 min with 28 MPa in Ar atmosphere. The phase compositions were investigated by X-ray diffraction (XRD); the surface morphology and topography of the crystal grains were also analyzed by scanning electron microscopy (SEM). The flexural strengths of Ti₂AlC and Ti₂AlSn_0.2C have been measured as 430 and 410 MPa, respectively. Both Vickers hardness decreased slowly as the load increased. The tribological behavior was investigated by dry sliding a low-carbon steel under normal load of 20-80 N and sliding speed of 10-30 m/s. Ti₂AlC bulk has a friction coefficient of 0.3-0.45 and a wear rate of (1.64-2.97)×10^-6 mm³/(N·m), while Ti₂AlSn_0.2C bulk has a friction coefficient of 0.25-0.35 and a wear rate of (2.5-4.31)×10^-6 mm³/(N·m). The influences of Sn incorporation on the microstructure and properties of Ti₂AlC have also been discussed.