Chloroamide precursors generated via a simple two-step ammonolysis reaction of transition metal chloride in the liquid phase at room temperature were heat treated in ammonia at moderate temperature to yield nano-sized VN crystallites. Grain growth inhibited by lowering the synthesis temperature (400oC) yielded agglomerated powders of spherical crystallites of cubic phase of VN with particle sizes as small as 6nm in diameter. X-ray diffraction, FTIR, mass spectroscopy (MS), and nuclear magnetic resonance (NMR) spectroscopy assessed the ammonolysis and nitridation reaction of the VCl4-NH3 system. X-ray Rietveld refinement, the BET technique and high-resolution transmission microscopy (HRTEM), energy dispersive x-ray (EDX) and thermogravimetric analysis (TGA) helped assess the crystallographic and microstructural nature of the VN nanocrystals. The surface chemistry and redox reaction leading to the gravimetric pseudo-capacitance value of (855F/g) measured for the VN nanocrystals was determined and validated using FTIR, XPS and cyclic voltammetry analyses.
Revised: June 18, 2018 |
Published: April 30, 2018
Citation
Choi D., P. Jampani Hanumantha, J.R. Jayakody, S.G. Greenbaum, and P.N. Kumta. 2018.Synthesis, Surface Chemistry and Pseudocapacitance Mechanisms of VN Nanocrystals Derived by a Simple Two-step Halide Approach.Materials Science and Engineering B: Advanced Functional Solid-state Materials 230.PNNL-SA-129110.doi:10.1016/j.mseb.2017.12.017