Efficient synthesis of nitrogen-doped carbon with flower-like tungsten nitride nanosheets for improving the oxygen reduction reactions

A novel three-dimensional (3D) electrocatalyst composite was successfully prepared through a facile hydrothermal method, consisting of tungsten nitride nanosheets with flower-like morphology (WN FNs) and nitrogen-doped carbon black (N–C). Highly crystalline WN FNs were observed to be uniformly distributed in N–C, and remarkably promoted the catalytic activities toward oxygen reduction reaction (ORR) of the N–C. Moreover, the electrochemical results proved that, WN FNs/N–C composite shows a significantly higher ORR activity with a 4-electron transfer pathway and limiting current density of 5.8 mA cm−2 in alkaline solutions. The stability test of the nanocomposite showed less degradation after 5 h and its methanol tolerance also was enhanced compared with Pt/C. The improved performance of the WN FNs/N–C composite can be attributed to its unique configuration and the increased exposure of active sites, which suggests that it could serve as an ideal candidate for developing high performance ORR catalysts.