A carbothermal NH3 reduction method was introduced for the synthesis of nanostructured tungsten carbonitride using support carbon and NH3 as carbon source and nitrogen source, respectively. A series of samples synthesized by this route from WO3/AC were characterized by X-ray diffraction, temperature-programmed surface reaction-mass spectroscopy, transmission electron microscopy, and microcalorimetry. The results demonstrated that a nanostructured tungsten carbonitride (WNxCy) was successfully synthesized on activated carbon at 800 degrees C and the resulting WNxCy was uniformly dispersed on the carbon support with particle size less than 2 nm. The WNxCy/AC prepared by the carbothermal NH3 process has stronger capability for CO adsorption and exhibited better catalytic performance for hydrazine decomposition than the WCx/AC-H catalyst prepared by the carbothermal H-2 reduction process. Further bench-scale tests indicated that it could be a promising substitute for the traditional Ir/Al2O3 catalyst in hydrazine decomposition technology. (C) 2016 Elsevier B.V. All rights reserved.