Synthesis and characterization of tungsten nitride (W2N) from WO3 and H2WO4 to be used in the electrode of electrochemical devices

Abstract

Tungsten nitride was synthesized from commercial WO3 and H2WO4, two precursors with different specific surface areas: 1.0 m2/g and 14.7 m2/g. The material was prepared by nitridation method by a thermal treatment at 873 K under NH3 flow. The W2N single phase was obtained with a crystal size of 15 nm and 11 nm, respectively, and with specific surface areas of 7.3 m2/g (from WO3) and 27.8 m2/g (from H2WO4). Both W2N exhibited high stability after a phosphoric acid attack. The W2N (WO3) powders show a high conductivity with a low activation energy (0.02 eV) measured by Electrochemical Impedance Spectroscopy. Those properties, that is, stability, high electronic conductivity and low activation energy make W2N a promising candidate to be used in the electrode of electrochemical devices in high corrosive environments.