A novel sulfur-nitrogen dual doped ordered mesoporous carbon electrocatalyst for efficient oxygen reduction reaction

Despite nitrogen doped carbon (NC) materials as metal-free electrocatalysts for oxygen reduction reaction (ORR) have shown desirable performance, the state-of-the-art of NC materials is still far from satisfaction for practical fuel cell applications. In the present work, sulfur (S) and nitrogen (N) dual doped ordered mesoporous carbon (SN-OMC) materials are for the first time successfully obtained by the aid of a convenient method under the same conditions, using polythiophene (PTh) and polypyrrole (PPy) as the precursors, ordered mesoporous silica (SBA-15) as the hard template, and FeCl3 as the catalyst. The preparation conditions of the adopted method are gentle and easy to control and regulate. The experimental results have demonstrated that the obtained materials possess high ordering degree, large specific surface area and adjustable sulfur and nitrogen contents. It is found that the S1N5-OMC (the PTh/PPy feeding volume ratio is 0.5:2.5) exhibits excellent ORR electrocatalytic activity in alkaline media with desirable current density, methanol tolerance and long-term stability. Such excellent performance could be attributed to the synergistic effect between S and N, the high density of catalytic sites for ORR provided by high S-N heteroatoms loading, and the excellent mass transfer benefiting from ordered mesoporous pore structure. The present investigation provides a new approach to prepare S and N dual doped mesoporous carbons, which show great potential to be applied as fuel cell cathode electrocatalysts.