Selective control of degree of nitridation of titanium oxynitride in carbon composites by adjusting trace oxygen under ammonia atmosphere

The degree of nitridation in titanium oxynitride synthesized via ammonia nitridation is a critical factor that significantly influences its properties. For composite systems containing titanium oxynitride and carbon derived from titanium polyacrylate, methods are required for the selective control of the degree of nitridation during ammonia-based heat-treatment without adversely affecting the carbon component, which serves as an electron conduction path. In this study, we demonstrate a strategy for selective nitridation control by thermally treating titanium complexes in an ammonia atmosphere containing trace amounts of coexisting oxygen. By adjusting the partial pressure of coexisting oxygen from 0 to 500 Pa, the degree of nitridation of titanium oxynitride could be tuned within the range of TiO 0.35 N 0.65 to TiO 0.86 N 0.14 , without compromising the degree of graphitization or electric double-layer capacitance. These results demonstrate that the thermal treatment of a titanium complex in an ammonia atmosphere with trace oxygen is a promising approach for fabricating titanium oxynitride/deposited carbon composite materials. • Selective control of the degree of nitridation in TiO 1- x N x /C was demonstrated. • TiO 1- x N x /C samples were prepared via ammonia nitridation of titanium polyacrylate. • The degree of nitridation was tuned by adding trace oxygen into the atmosphere. • Trace oxygen exerted a minor impact on deposited carbon.