The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace (BF) slag was studied using confocal scanning laser microscopy (CSLM). Results showed that perovskite was the primary phase formed during the cooling of slag. On the slag surface, the growth of perovskite proceeded via the successive production of quasi-particles along straight lines, which further extended in certain directions. The morphology and structure of perovskite was found to vary as a function of cooling rate. At cooling rates of 10 and 30 K/min, the dendritic arms of perovskite crossed obliquely, while they were orthogonal at a cooling rate of 20 K/min and hexagonal at cooling rates of 40 and 50 K/min. These three crystal morphologies thus obtained at different cooling rates respectively corresponded to the orthorhombic, cubic and hexagonal crystal structures of perovskite. The observed change in the structure of perovskite could probably be attributed to the deficiency of O²⁻, when Ti₂O₃ was involved in the formation of perovskite.

Nanoscale (VNbTaZrHf)C high-entropy carbide (HEC) powders were prepared by electrochemical reduction in CaCl₂ molten salt at 1173 K using the mixture of the individual metal oxides and graphite. The product of (VNbTaZrHf)C HEC powders with a face-centred cubic (fcc) structure can be prepared by this method and the particle size is below 100 nm. The moderate processing temperature is beneficial to prevent the in-situ sintering growth of the ultra-high melting HEC particles. The supercapacitive behaviour of the prepared HEC is evaluated in a three-terminal electrochemical cell with the intention of exploring the potential of supercapacitor applications. The specific capacitance of 50 F/g is achieved at a scan rate of 10–100 mV/s in 1 M KOH, and the capacity retention is 89% after 2500 full cycles. This excellent supercapacitive behaviour makes (VNbTaZrHf)C HEC a promising candidate for supercapacitor applications due to its high entropy effect and nanoscale structure.

Nanostructured metal carbides have numerous applications in catalysis and energy storage. However, directional construction remains a significant challenge. In this work, a novel strategy for the direct synthesis of nanostructured metal carbides using nanostructured metal oxides as the precursor is developed. TiO₂ nanotube arrays (TiO₂ NTAs) can be successfully transformed into TiC nanotube arrays (TiC NTAs) through electro-deoxidation and carbonization reactions in a low-temperature molten salt. TiC NTAs have a highly oriented and ordered array structure, which shows the advantages of large specific surface area, direct electron transport, and good chemical stability. Here, TiC NTA electrodes and PVA-H₃PO₄ electrolyte gel were assembled into a flexible quasi-solid-state supercapacitor to characterize their energy storage performance. The results show that the TiC NTA electrodes exhibit a high areal capacitance of 53.3 mF cm⁻², excellent cycling stability, and mechanical flexibility. Moreover, the energy densities can reach 4.6 μW h cm⁻² at a power density of 78.9 μW cm⁻². This work provides a new strategy for the directed synthesis of nanostructured metal carbides and demonstrates the energy storage application potential of TiC NTAs. It is expected that this work will contribute to the development of the synthesis and application of nanostructured metal carbides.

V ₂ AlC is a typical ternary intermetallic compound and a precursor to synthesis 2D-MXenes V ₂ C. This work used cheap metal oxides and carbon as simple starting materials to fabricate MAX phases carbide V ₂ AlC by molten salt electrolysis, and the obtained product could be converted into 2D V ₂ C by a chemical etching process easily. The obtained ultrafine V ₂ AlC possess high purity and homogeneity, and the 2D V ₂ C from the chemical etching presented a unique layered Nano-sheets structure. TEM and X-ray photoelectron spectroscopy were combined to analysis the micromorphology and the chemical bonding states. And the reaction mechanism has been investigated to explore the facile synthetic method of V ₂ AlC and 2D V ₂ C.