Single-source precursor derived high-entropy metal–carbide nanowires: Microstructure and growth evolution

Abstract

In recent years, high-entropy metal carbides (HECs) have attracted significant attention due to their exceptional physical and chemical properties. The combination of excellent performance exhibited by bulk HEC ceramics and distinctive geometric characteristics has paved the way for the emergence of one-dimensional (1D) HECs as novel materials with unique development potential. Herein, we successfully fabricated novel (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C nanowires derived via Fe-assisted single-sourced precursor pyrolysis. Prior to the synthesis of the nanowires, the composition and microstructure of (Ti,Zr,Hf,Nb,Ta)-containing precursor (PHECs) were analyzed, and divinylbenzene (DVB) was used to accelerate the conversion process of the precursor and contribute to the formation of HECs, which also provided a partial carbon source for the nanowire growth. Additionally, multi-branched, single-branched, and single-branched bending nanowires were synthesized by adjusting the ratio of PHECs to DVB. The obtained single-branched (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C nanowires possessed smooth surfaces with an average diameter of 130–150 nm and a length of several tens of micrometers, which were a single-crystal structure and typically grew along the [11¯1] direction. Also, the growth of the (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C nanowires was in agreement with top-type vapor–liquid–solid mechanism. This work not only successfully achieved the fabrication of HEC nanowires by a catalyst-assisted polymer pyrolysis, but also provided a comprehensive analysis of the factors affecting their yield and morphology, highlighting the potential application of these attractive nano-materials.

Keywords

• (ti0.2zr0.2hf0.2nb0.2ta0.2)c nanowires
• high-entropy metal carbides (hecs)
• (ti,zr,hf,nb,ta)-containing precursors
• vapor–liquid–solid (vls) mechanism