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 the excellent performance exhibited by bulk HECs ceramics and the distinctive geometric characteristics has paved the way for the emergence of one-dimensional (1D) HECs as a novel material with unique development potential. Herein, we successfully fabricated a novel (Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)C nanowire 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 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 (Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)C nanowires possessed smooth surfaces with an average diameter of 130~150 nm and a length of several tens of micrometers, which were single-crystal structure and typically grew along [11(_)1] direction. And the growth of (Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)C nanowires was in agreement with top-type vapor-liquid-solid mechanism. This work not only successfully achieved the fabrication of HECs 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.