Synthesis of an ordered porous carbon with the dual nitrogen-doped interfaces and its ORR catalysis performance

Abstract

Both nitrogen-doping feature and pore structure are critical factors for developing nitrogen-doped carbons based catalysts with a high performance toward oxygen reduction reaction (ORR). Herein, a simple one-step CVD of acetylene and acetonitrile vapor method using silanized SBA-15 as a template has been developed to synthesize an ordered porous carbon (OPC) with dual nitrogen-doped interfaces. The optimized sample as prepared with the CVD of 4 h at 750 °C contains two types of ordered mesopores that one type is the ordered cylindrical pores inheriting from the pores of SBA-15 and has a pore width of 4.0∼5.0 nm, the other type is the ordered quasi-hexagonal pores with a width of 3.0∼4.0 nm produced by etching the pore walls of SBA-15. These two types of pores whose pore walls are built by the nitrogen doped carbon layers resulted by the CVD and thus it actually makes the dual nitrogen-doped interfaced OPC (DN-OPC). Meanwhile, DN-OPC contains a few of micropores and a large SSA of 1430 m2/g. This dual-ordered pores and dual nitrogen-doped interfaces cannot only facilitate mass transport but also utilize the active sites of DN-OPC for ORR. Therefore, as metal-free ORR catalyst, DN-OPC exhibits a good activity close to commercial Pt/C catalyst, and an excellent durability and methanol tolerance.