Nitrogen and sulfur co-doped mesoporous hollow carbon microspheres for highly efficient oxygen reduction electrocatalysts

Abstract Heteroatom-doped porous carbons are considered as one of the most promising metal-free electrocatalysts for highly efficient electrocatalytic reactions. Herein, nitrogen and sulfur co-doped mesoporous hollow carbon microspheres are fabricated using a feasible process involving the pyrolysis of polydopamine in the presence of sodium 1,5-naphthalenedisulfonate (1,5-NDSNa) and the use of mesoporous silica SBA-15 as hard template. The resultant carbon microspheres have a well-developed hierarchical porosity with large surface area, showing high-efficiency electrochemical oxygen reduction activity in alkaline media, along with much enhanced stability and methanol tolerance, as compared with those of commercial platinum catalysts. The superior electrocatalytic performance and stability of the catalyst might be due to the synergistic effect between N and S elements and the well-defined meso- and macroporosity, presenting great potential in the fields of fuel cells and metal-air batteries.