Synthesis and Characterization of CuNb2O6 from an Oxalic Precursor Via Solid State Reaction

Abstract

The present paper's objective was to synthesize and characterize both the oxalic niobium precursor (NH 4 ) 3 NbO(C 2 O 4 ) 3 .H 2 O, and the product of its doping with Cu and calcining, CuNb 2 O 6 . In order to obtain the niobium precursor, commercially available niobium oxide (Nb 2 O 5 ) was subject to fusion with potassium bisulfate (KHSO 4 ). Once leached with water, the powder was complexed with oxalic acid and ammonium oxalate. The as produced material was manually mixed with copper nitrate Cu(NO 3 ) 2 .2H 2 O (25% Cu molar) and calcined at 1000°C in a muffle furnace. CuNb 2 O 6 was then obtained. The precursor was characterized by XRD, SEM, FT-IR, XRF, TG/DTG. The calcination product was characterized by XRD, XRF and SEM. Results show that single phase CuNb 2 O 6 could be obtained by this method without Nb 2 O 5 contamination.

Synthesis and Characterization of Niobium Carbide with Copper Addition Obtained Via Gas Solid Reaction

“…Copper doped niobium carbide (Cu-NbC) was synthesized via gas solid reaction in a fixed bed reactor using as a starting material finely grained precursor ammoniobium (V) oxalate 21 . The dopant addition was carried out by simple physical mixture of powders in the solid state with an agate mortar and pestle until visual uniformity of the powder.…”

“…This precursor's use for the synthesis of niobium powders has been proved feasible and interesting as it presents higher reactivity than the commercial niobium pentoxide 21 . Other authors 22 have successfully produced NbC in shorter time and temperature using this material as niobium source.…”

Production of Niobium Nitride Via Nitrogen-Based Solid-Gas Reaction

“…Increasing the flow rate to a certain level tends to reduce the physical resistance to mass transfer, allowing us to know the predominant characteristics of chemical reactions, as well as reducing the residence time of the gas inside the reactor 24 . Based on the results of the literature, the stoichiometries of the niobium precursor transformation can be written as follows [25][26][27] :…”