Ultrasmall tungsten carbide catalysts stabilized in graphitic layers for high-performance oxygen reduction reaction

Tungsten carbide (WC) has been proven Pt-like features in many catalytic reactions, and presents promising potentials to substitute noble metal-based electrocatalysts. However, the catalytic performances cannot be improved to the industrial standard due to the low density of catalytically active sites that are relevant to the size and stability of catalysts. Herein, we synthesized WC catalysts with a mean diameter of 1.9±0.9 nm, comprising a high density of single W atoms, sub-nanometer and nanometer WC clusters, which are completely encapsulated in high-defective graphitic layers (WC@C). Such high-defective graphitic layers not only improve the overall conductivity for accelerating the penetration and exchange of ions and electrons during the electrocatalytic process of oxygen reduction, but also suppress the chemical/thermal coarsening of WC catalysts, thus providing excellent electrocatalytic performances in four-electron transfer process for oxygen reduction reaction.