Electrocatalytic oxygen reduction on nitrogen-doped porous carbon spheres prepared with resorcinol–phenolsulfonic acid–formaldehyde mixed resins

Resorcinol–phenolsulfonic acid–formaldehyde (RxPS1–xF) mixed resin spheres were prepared by using high-temperature hydrothermal synthesis. Pyrolysis of the resin spheres under a NH3 atmosphere produced small, porous, conductive N-doped carbon spheres. These carbon spheres promoted an electrocatalytic oxygen reduction reaction with almost 100% four-electron reduction selectivity and their performance was comparable to that of the state-of-the-art Pt/C catalyst.