Elektrochemische Synthese von nanostrukturiertem Antimon und nanostrukturierten Antimonverbindungen in ionischen Flüssigkeiten

In this work, the electrochemical deposition of 3DOM Sb, Sb nanowires, semiconducting nanoparticles of AlxSb1-x compound (0<x<1), InSb nanoparticles, 3DOM Cu2Sb and Cu2Sb nanoparticles in ionic liquids were investigated. Cyclic voltammetry (CV), chronoamperometry, chronopotentiometry, and electroless deposition were employed for the electrochemical synthesis of the materials. Scanning electron microscopy (SEM) was used for structural characterization, energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) for chemical composition, X-ray diffraction (XRD) for crystal structure and UV/Vis spectrometry for band gap. In 0.1 M SbCl3/[EMIm]TFSA and 0.3 M SbCl3/[EMIm]TFSA, 3DOM Sb was electrochemical obtained on the polystyrene (PS) sphere templates (PS spheres covered Au and PS spheres covered Fe, respectively). During deposition, the high negative current damages the 3DOM structure of the template. The generation of Sb with 3DOM structure depends on the deposition parameters, such as concentration of SbCl3, deposition potential, deposition time, and substrate. For the first time, the electrochemical deposition of Sb nanowires in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([BMP]TFSA) with SbCl3 is successful without template and additives. The results show that the current density during deposition is the criterion for the template- and additive-free formation of Sb nanowires. From SEM images, the growth model of the Sb nanowires can be inferred as follows: The deposited particles in the first layer on the working electrode serve as nanocores, from which nanowires can grow. During the growth process, sometimes some nanowires approach each other and continue to grow in a plane. Under different concentrations (from 0.3 M to 0.6 M), temperatures (from room temperature to 80 °C) and on different substrates (Fe, Au, and ITO) in [BMP]TFSA, Sb nanowires could be successfully obtained without template and additive. High temperature promotes the quality of nanowires. The success of the synthesis of Sb nanowires in [BMP]TFSA and 1-butyl-1-methylpyrrolidinium triflate ([BMP]TFO) and the failure in [EMIm]TFSA show that the composition of ionic liquids affects the structure of the deposition products and the influence of the cation is more important than that of the anion. InSb nanoparticles were obtained by co-deposition in 0.05 M InCl3 and 0.03 M SbCl3 in [BMP]TFSA at room temperature on Au at -2.2 V for 12 h. In 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and [EMIm]TFSA, Sb was synthesized by the electroless deposition. Co-deposition of AlSb was carried out in AlCl3/[EMIm]Cl (60/40 mol%) with SbCl3 of different concentrations and deposition potentials at 70 °C. Using UV/Vis spectrometry and Tauc-plot method, the semiconducting AlxSb1-x compound (0<x<1) was detected in the products obtained by co-deposition in AlCl3/[EMIm]Cl (60/40 mol%) with 0.15 M SbCl3 or 0.02 M SbCl3. The band gap of the deposit in AlCl3/[EMIm]Cl (60/40 mol%) with 0.02 M SbCl3 at -1.0 V for 15 min is closest to the theoretical value (1,6 eV), which is 1.3±0.1 eV. No semiconducting products were obtained in [EMIm]TFSA in the co-deposition. The reaction between Cu and SbCl3 in some ionic liquids (1-butyl-1-methylpyrrolidinium dicyanamide ([BMP]DCA), [BMP]TFSA, [BMP]TFO, [EMIm]TFSA, and 1-Ethyl-3-methylimidazolium triflate ([EMIm]TFO)) shows different reaction rates and products, which is a response to the different compositions of the ionic liquids. The electroless deposition of 3DOM-Cu2Sb in [EMIm]TFSA is successful through two steps: Cu deposition from CuCl2/[BMP]DCA on Fe covered with PS spheres and electroless deposition of Cu2Sb from deposited Cu in SbCl3/[EMIm]TFSA. Co-deposition of Cu2Sb was in [BMP]DCA carried out. 0.3 M CuCl2 and 0.2 M SbCl3 in [BMP]DCA promote the Cu2Sb synthesis.