Dual-Functional NaCl Template Strategy towards Synthesis of Metal-Free Sulfur/nitrogen co-Doped Carbon Nanosheets Catalysts for Oxygen Reduction Reaction

Developing eco-friendly, high-efficiency and cost-effective catalysts for oxygen reduction reaction are significantly crucial for the application of direct-methanol fuel cells. The metal-free sulfur/nitrogen in-situ co-doped carbon nanosheets are prepared through polymerization process and carbonization process using aniline as a nitrogen source, 4-aminobenzenesulfonamide as a sulfur source and NaCl as a template and protective layer. The obtained catalysts show the obvious two dimensional nanosheet structure with successful doping of S and N. Benefiting from high contents of S atoms and N atom, high special surface area and graphitic degree, well-ordered micropores and synergetic interaction between thiophenic-S, pyridinic N and graphitic N, the optimal catalyst S3/N-CNS800 shows excellent oxygen reduction performance with 13.2mV more positive half-wave potential than that of 20% Pt/C, superior long-term durability and tolerance to methanol cross-over.