Niobium (Nb) is primarily used as the active material in Nb electrolytic capacitors in the form of metallic fine powder. Unlike traditional methods of preparing niobium powder through chemical or electrochemical reduction of metal compounds in molten salts, we report here the efficient preparation of Nb nanopowder via electrolysis of NbS 2 in the NaCl-KCl melt at 973 K. The NbS 2 is simply synthesized by carbo-sulfidation of Nb 2 O 5 . The following electro-desulfidation in the molten electrolyte converts solid NbS 2 into Nb nanopowder at the cathode, with S 2- ions moving to the anode and being oxidized to gaseous sulfur. The reduction path was verified to be NbS 2 → L x NbS 2 → NbS 2-w → Nb. Through constant cell electrolysis at 2.9 V, NbS 2 is rapidly reduced to nodular Nb nanopowder (50-100 nm), with a Current efficiency and energy consumption of approximately 94% and 3.58 kW·h kg⁻¹ Nb, respectively.
Kangkang Wang,Zhouyi Guo,Yang Li,Yanxian Guo,Hao Liu,Wen Zhang,Zhengzhi Zou,Yanling Zhang,Zhiming Liu
Recently, two-dimensional (2D) semiconductor materials have been the focus of substantial research interest in surface-enhanced Raman scattering (SERS) because of their fascinating and unique properties. Herein, 2D niobium ditelluride (NbTe2) nanosheets (NTNs) with the lamellar and ultrathin crystalline morphologies were easily synthesized for the first time via liquid-phase exfoliation combined with the hydrothermal method. NTNs could serve as a low-cost metal-free 2D SERS substrate for the ultrasensitive detection of aromatic molecules and antibiotics because of the fluorescence quenching effect and the charge transfer enhancement mechanism. The enhancement factor of NTNs can be up to 5.59 × 106 with expanding the ultralow limit of detection (LOD) to 10–9 M, which approached that of metal-based SERS substrates. Good reproducibility and uniformity were also acquired on the 2D substrate and facilitated the reliable SERS analysis of ciprofloxacin (CIP) and enrofloxacin (ENR) at a low concentration, which exhibited LODs of 35.1 and 35.9 ppb, respectively. The 2D SERS substrates with remarkable SERS sensitivity and specificity may pioneer the applications of telluride-based materials for food and drug safety detection.
危险品化学品经营许可证（带存储）